I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?
Thanks,
Eric

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

Welding around the existing rivets won't fix an overstress problem.

Is the boat made of a weldable alloy?

Joe Gwinn

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

It would work nicely on a small boat, but it would be pretty tricky,
because epoxy bonding to aluminum is extremely weak unless the surface
is properly prepared. It also would depend on having plenty of overlap
at the joint.

If it were me, I'd double-up on the rivets, then drill out the old
ones and replace them, too.

I had such a Sears jon boat, back in the '60s. Mine was built by
Grumman. Sears used all kinds of suppliers, even including Fairchild
Aircraft.


Welding around the existing rivets won't fix an overstress problem.

Is the boat made of a weldable alloy?

FWIW, I think they all are. Most are made of 5052 or 5083/5086. Some
6061 is used for ribs, etc. All are weldable; the 5XXX series is more
common and more weldable.

Joe Gwinn

--
Ed Huntress

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds will
add some drag but I really don't care, the only bodies of water this
boat will be going in are small so even if the motor quits the rowing
distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

Welding around the existing rivets won't fix an overstress problem.

Is the boat made of a weldable alloy?

Or it's a really old boat.

I was told -- and I don't know if this is true -- that truck frames are
riveted because that allows for a little bit of flexing on overload, so
the frame may get tweaked but it won't get ripped apart.

I don't know if this applies to the boat or not, but my inclination would
be to either keep it all riveted, or make it all welded, but don't muck
around with welding up some rivets and leaving the rest in their virgin
state.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

wrote in message ...

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?
Thanks,
Eric
================================================== =============

I would be really afraid that when you weld on the head of a tight rivet,
the heat cycling will allow it to loosen, and what you will wind up with is
all loose rivets with the heads welded to the outside sheet. The rivet is
under tension now, heat it and it will weaken and if it gets too weak it
will yield to relieve that tension, and when it cools it will be loose -
that's my theory, anyway. I agree that you should double up the number of
rivets, add the new ones first then drill out the old ones so you wind up
with twice as many all new rivets.

-----
Regards,
Carl Ijames

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

I didn't know about the use for steel in automobiles. I am interested,
actually.

I wonder how the Russians built the MIG-25 fighters, which were made of
steel foil. Search. Wikipedia says that they used a weldable nickel
steel alloy.


It would work nicely on a small boat, but it would be pretty tricky,
because epoxy bonding to aluminum is extremely weak unless the surface
is properly prepared. It also would depend on having plenty of overlap
at the joint.

Yes to all of it. I wasn't suggesting this approach here, but was
making the point about the necessity of stress spreading. For one
thing, one would need to drill all rivets and disassemble the boat, to
allow adequate surface prep. Apply goop and rivet back together, then
put in the autoclave and bake at 300F overnight. No autoclave? Hmm.
That is a problem. The airplane companies have all manner of
clamp-and-heat fixtures for this.


If it were me, I'd double-up on the rivets, then drill out the old
ones and replace them, too.

So we would end up with three times the number of rivets? That ought
to do it.


I had such a Sears jon boat, back in the '60s. Mine was built by
Grumman. Sears used all kinds of suppliers, even including Fairchild
Aircraft.


Welding around the existing rivets won't fix an overstress problem.

Is the boat made of a weldable alloy?

FWIW, I think they all are. Most are made of 5052 or 5083/5086. Some
6061 is used for ribs, etc. All are weldable; the 5XXX series is more
common and more weldable.

My recollection was the same, that 5xxx series alloys were used, which
would make it weldable. But my sight-unseen guess would be that one
would do seam welds of the sheets to one another, and ignore the
rivets. This actually sounds like a good application of gas welding,
and was used to make airplanes in WW2. Though they used billions of
rivets too.

Joe Gwinn

On Sun, 31 Aug 2014 09:22:28 -0700, wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?
Thanks,
Eric
===============
Why not just clean it up good, goober the seams and rivets
with silicone seal (inside and out if desired) and repeat as
necessary. This ain't a space capsule.
http://tinyurl.com/ng8y8rn
http://tinyurl.com/jwsqq34


--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"

Sandpaper and JB weld.

On Sun, 31 Aug 2014 09:22:28 -0700, wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?
Thanks,
Eric

Personally..Id coat the rivets with 3M 5200 (1 week cure) and never
worry about it again.

But there are tons of information on the Web that can be simply found
by googling Aluminum Boat rivets leaking

Gunner

"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

On Sun, 31 Aug 2014 16:25:36 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

Jerry Mayfield, who was an editor at AvWeek in the late '70s and early
'80s, and I used to compete to scoop each other on aerospace
manufacturing techniques (I was two floors below him, at American
Machinist). He had the advantage of being weekly, to my monthy, but I
beat him on single-crystal turbine blades and bismuth-alloy brazing .
g


I didn't know about the use for steel in automobiles. I am interested,
actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.



I wonder how the Russians built the MIG-25 fighters, which were made of
steel foil. Search. Wikipedia says that they used a weldable nickel
steel alloy.

Good question. They couldn't use titanium because they hadn't figured
out how to seam-weld it (we used electron-beam welding in a vacuum,
starting, I think, with the F-111).

I don't know how they wound up joining it.



It would work nicely on a small boat, but it would be pretty tricky,
because epoxy bonding to aluminum is extremely weak unless the surface
is properly prepared. It also would depend on having plenty of overlap
at the joint.

Yes to all of it. I wasn't suggesting this approach here, but was
making the point about the necessity of stress spreading. For one
thing, one would need to drill all rivets and disassemble the boat, to
allow adequate surface prep. Apply goop and rivet back together, then
put in the autoclave and bake at 300F overnight. No autoclave? Hmm.
That is a problem. The airplane companies have all manner of
clamp-and-heat fixtures for this.

Yeah, but you can get over half the strength of A-B cure high-temp
epoxies with good room-temperature-cure material. That should be
plenty.




If it were me, I'd double-up on the rivets, then drill out the old
ones and replace them, too.

So we would end up with three times the number of rivets? That ought
to do it.

Hmmm. I meant double the number. I guess that was ambiguous.



I had such a Sears jon boat, back in the '60s. Mine was built by
Grumman. Sears used all kinds of suppliers, even including Fairchild
Aircraft.


Welding around the existing rivets won't fix an overstress problem.

Is the boat made of a weldable alloy?

FWIW, I think they all are. Most are made of 5052 or 5083/5086. Some
6061 is used for ribs, etc. All are weldable; the 5XXX series is more
common and more weldable.

My recollection was the same, that 5xxx series alloys were used, which
would make it weldable. But my sight-unseen guess would be that one
would do seam welds of the sheets to one another, and ignore the
rivets. This actually sounds like a good application of gas welding,
and was used to make airplanes in WW2. Though they used billions of
rivets too.

Joe Gwinn

It would be good for gas welding -- for someone who is really good at
it. I consider myself lucky to weld two aluminum tabs together;
without punching holes. But Kent White (the Tinman) has some great
info on it.

--
Ed Huntress

On Mon, 01 Sep 2014 08:55:12 -0700, wrote:

On Sun, 31 Aug 2014 16:26:24 -0700 (PDT),
wrote:

Sandpaper and JB weld.
Thanks everyone for the suggestions and opinions. Yesterday I decided
to try welding over a couple rivets because I was welding some cracks
anyway. MIG welding didn't work because of crud trapped under the
rivet head and TIG welding did OK because I was able to boil some of
the dirt out but was still a bad solution. Since there over 100 rivets
I'm going to order a couple hundred closed end blind rivets and borrow
an air powered rivet puller. I'll drill out the old rivets, clean up
the area some, dip the rivets in sealant made for the purpose, and
install 'em. I found a few sealants that are made for use under a
rivet but none that work outside for any length of time. JB Weld will
not work by the way. I know all about abrading aluminum surfaces
wetted with epoxy, and it does work, but this method can only be used
on the outside of the hull on this boat. And epoxy patches on the
outside don't fare so well with beaching the boat.
Eric

3M 5200 is the sealant you want to use.


"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

On Mon, 01 Sep 2014 13:34:17 -0500, Richard
wrote:

On 8/31/2014 1:05 PM, Ed Huntress wrote:
On Sun, 31 Aug 2014 13:37:34 -0400, Joe
wrote:

In ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?



If it's so old that the rivets are leaking you have more problems than
just leaky rivets.

Like metal fatigue - concentrated around the leaky rivets.

I would not even bother trying to weld or rivet.

Maybe coat the bottom with truck bed liner?

Or recycle it for aluminum scrap?

Truck bed lining can be had in a multitude of colors...including
white, tan and light brown

http://www.ebay.com/itm/SPRAY-ON-BLA...-/171040297720


"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

Why not just clean it up good, goober the seams and rivets
with silicone seal (inside and out if desired) and repeat as
necessary. This ain't a space capsule.
http://tinyurl.com/ng8y8rn
http://tinyurl.com/jwsqq34

this was my solution on a very old canoe, worked but i always brought
silicone along for long trips

On Sun, 31 Aug 2014 20:40:09 -0400, Ed Huntress
wrote:

On Sun, 31 Aug 2014 16:25:36 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

Jerry Mayfield, who was an editor at AvWeek in the late '70s and early
'80s, and I used to compete to scoop each other on aerospace
manufacturing techniques (I was two floors below him, at American
Machinist). He had the advantage of being weekly, to my monthy, but I
beat him on single-crystal turbine blades and bismuth-alloy brazing .
g


I didn't know about the use for steel in automobiles. I am interested,
actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.



I wonder how the Russians built the MIG-25 fighters, which were made of
steel foil. Search. Wikipedia says that they used a weldable nickel
steel alloy.

Good question. They couldn't use titanium because they hadn't figured
out how to seam-weld it (we used electron-beam welding in a vacuum,
starting, I think, with the F-111).


I believe that the SR-71 came first :-)

I don't know how they wound up joining it.



It would work nicely on a small boat, but it would be pretty tricky,
because epoxy bonding to aluminum is extremely weak unless the surface
is properly prepared. It also would depend on having plenty of overlap
at the joint.

Yes to all of it. I wasn't suggesting this approach here, but was
making the point about the necessity of stress spreading. For one
thing, one would need to drill all rivets and disassemble the boat, to
allow adequate surface prep. Apply goop and rivet back together, then
put in the autoclave and bake at 300F overnight. No autoclave? Hmm.
That is a problem. The airplane companies have all manner of
clamp-and-heat fixtures for this.

Yeah, but you can get over half the strength of A-B cure high-temp
epoxies with good room-temperature-cure material. That should be
plenty.




If it were me, I'd double-up on the rivets, then drill out the old
ones and replace them, too.

So we would end up with three times the number of rivets? That ought
to do it.

Hmmm. I meant double the number. I guess that was ambiguous.



I had such a Sears jon boat, back in the '60s. Mine was built by
Grumman. Sears used all kinds of suppliers, even including Fairchild
Aircraft.


Welding around the existing rivets won't fix an overstress problem.

Is the boat made of a weldable alloy?

FWIW, I think they all are. Most are made of 5052 or 5083/5086. Some
6061 is used for ribs, etc. All are weldable; the 5XXX series is more
common and more weldable.

My recollection was the same, that 5xxx series alloys were used, which
would make it weldable. But my sight-unseen guess would be that one
would do seam welds of the sheets to one another, and ignore the
rivets. This actually sounds like a good application of gas welding,
and was used to make airplanes in WW2. Though they used billions of
rivets too.

Joe Gwinn

It would be good for gas welding -- for someone who is really good at
it. I consider myself lucky to weld two aluminum tabs together;
without punching holes. But Kent White (the Tinman) has some great
info on it.
--
Cheers,

John B.

On Mon, 01 Sep 2014 06:34:58 -0500, Karl Townsend
wrote:


Why not just clean it up good, goober the seams and rivets
with silicone seal (inside and out if desired) and repeat as
necessary. This ain't a space capsule.
http://tinyurl.com/ng8y8rn
http://tinyurl.com/jwsqq34

this was my solution on a very old canoe, worked but i always brought
silicone along for long trips
I had a really old aluminum canoe that had been retired from rental
service in Algonquin park that had been bashed around, taken over
beaver dams, and generally well abused before I got it which had 2 or
3 gashes welded and a few missing rivets "plug welded". In the 15 or
more years I subsequently owned it, it never leaked or squeaked. I
sold it to a friend who used it at their family cottage for another 8
years or so, and sold it with the cottage 2 years ago. This was a
pretty heavy "springbock" canoe. Not sure how it would work on a
lightweight Grumman, but I have no reason to believe there would be
any problem, with the Grumman being 6061 about half the thickness.

On Sun, 31 Aug 2014 16:28:01 -0500, F. George McDuffee
wrote:

On Sun, 31 Aug 2014 09:22:28 -0700, wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?
Thanks,
Eric
===============
Why not just clean it up good, goober the seams and rivets
with silicone seal (inside and out if desired) and repeat as
necessary. This ain't a space capsule.
http://tinyurl.com/ng8y8rn
http://tinyurl.com/jwsqq34
Putting sealant on the rivets does not work long term. I have tried
this in the past. I have tried several different sealants and the only
one that worked for more than a year was this black stuff that
remained gooey forever.
Eric

On Sun, 31 Aug 2014 16:26:24 -0700 (PDT),
wrote:

Sandpaper and JB weld.
Thanks everyone for the suggestions and opinions. Yesterday I decided
to try welding over a couple rivets because I was welding some cracks
anyway. MIG welding didn't work because of crud trapped under the
rivet head and TIG welding did OK because I was able to boil some of
the dirt out but was still a bad solution. Since there over 100 rivets
I'm going to order a couple hundred closed end blind rivets and borrow
an air powered rivet puller. I'll drill out the old rivets, clean up
the area some, dip the rivets in sealant made for the purpose, and
install 'em. I found a few sealants that are made for use under a
rivet but none that work outside for any length of time. JB Weld will
not work by the way. I know all about abrading aluminum surfaces
wetted with epoxy, and it does work, but this method can only be used
on the outside of the hull on this boat. And epoxy patches on the
outside don't fare so well with beaching the boat.
Eric

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 16:25:36 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

Jerry Mayfield, who was an editor at AvWeek in the late '70s and early
'80s, and [we] used to compete to scoop each other on aerospace
manufacturing techniques (I was two floors below him, at American
Machinist). He had the advantage of being weekly, to my monthy, but I
beat him on single-crystal turbine blades and bismuth-alloy brazing.
g

Not just for airplanes. I've seen aluminum brazing used to fabricate
aluminum heat sinks for water-cooled radar transmitter modules.


I didn't know about the use for steel in automobiles. I am interested,
actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.

Thanks. I've printed the article out for reading.


I wonder how the Russians built the MIG-25 fighters, which were made of
steel foil. Search. Wikipedia says that they used a weldable nickel
steel alloy.

Good question. They couldn't use titanium because they hadn't figured
out how to seam-weld it (we used electron-beam welding in a vacuum,
starting, I think, with the F-111).

Or the SR-71, as has been pointed out.


I don't know how they wound up joining it.

The Russians do have the capacity to forge an entire fighter airframe
from titanium, which eliminated the need to weld titanium.

In the US, I recall plans to have an entire factory with an argon
atmosphere (and people in spacesuits) to work titanium. Don't know
what happened though.

Titanium is pretty springy, with lots of spring-back. Don't know how
well titanium rivets work.


It would work nicely on a small boat, but it would be pretty tricky,
because epoxy bonding to aluminum is extremely weak unless the surface
is properly prepared. It also would depend on having plenty of overlap
at the joint.

Yes to all of it. I wasn't suggesting this approach here, but was
making the point about the necessity of stress spreading. For one
thing, one would need to drill all rivets and disassemble the boat, to
allow adequate surface prep. Apply goop and rivet back together, then
put in the autoclave and bake at 300F overnight. No autoclave? Hmm.
That is a problem. The airplane companies have all manner of
clamp-and-heat fixtures for this.

Yeah, but you can get over half the strength of A-B cure high-temp
epoxies with good room-temperature-cure material. That should be
plenty.

I did a lot of gluing for NASA as a summer employee in the late 1960s,
and we used 180 F (82 C). Higher is better, but many electronic
components could not tolerate soaking at 300 F for very long.


If it were me, I'd double-up on the rivets, then drill out the old
ones and replace them, too.

So we would end up with three times the number of rivets? That ought
to do it.

Hmmm. I meant double the number. I guess that was ambiguous.

Copy editor sought. Apply within.


I had such a Sears jon boat, back in the '60s. Mine was built by
Grumman. Sears used all kinds of suppliers, even including Fairchild
Aircraft.


Welding around the existing rivets won't fix an overstress problem.

Is the boat made of a weldable alloy?

FWIW, I think they all are. Most are made of 5052 or 5083/5086. Some
6061 is used for ribs, etc. All are weldable; the 5XXX series is more
common and more weldable.

My recollection was the same, that 5xxx series alloys were used, which
would make it weldable. But my sight-unseen guess would be that one
would do seam welds of the sheets to one another, and ignore the
rivets. This actually sounds like a good application of gas welding,
and was used to make airplanes in WW2. Though they used billions of
rivets too.

Joe Gwinn

It would be good for gas welding -- for someone who is really good at
it. I consider myself lucky to weld two aluminum tabs together;
without punching holes. But Kent White (the Tinman) has some great
info on it.

I bet welding is also pretty slow compared to riveting.

Joe Gwinn

On Mon, 01 Sep 2014 12:07:57 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 16:25:36 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

Jerry Mayfield, who was an editor at AvWeek in the late '70s and early
'80s, and [we] used to compete to scoop each other on aerospace
manufacturing techniques (I was two floors below him, at American
Machinist). He had the advantage of being weekly, to my monthy, but I
beat him on single-crystal turbine blades and bismuth-alloy brazing.
g

Not just for airplanes. I've seen aluminum brazing used to fabricate
aluminum heat sinks for water-cooled radar transmitter modules.

Right. furnace brazing is, or was, quite common in aluminum, and
automobile radiators have been some of the biggest users.

The bismuth-alloy technique is something different. It applies to
joining superalloys, such as Hastelloy, and the P&W job I watched it
being used on was for turbine-blase halves. It may work with other
alloys; I don't know.

The brazing foil is made of Hastelloy with a small amount of bismuth
added. The bismuth lowers the melting point; the objective in this
case is to drop it about 50 deg. F.

The parts and foil are placed in an oven at something like 10 deg. F
below the melting point of the parent metal. The foil metls and the
bismuth diffuses into the parent metal. As it does, the melting point
of the foil rises; the temperature is raised a few degrees; and the
joint solidifies at that temperature.

The bismuth has no significant effect on the melting point of the
parent metal. The finished joint has a melting temperature within
around 5 deg. F of the parent metal. The finished assembly is
virtually a solid piece with uniform metallurgy.




I didn't know about the use for steel in automobiles. I am interested,
actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.

Thanks. I've printed the article out for reading.


I wonder how the Russians built the MIG-25 fighters, which were made of
steel foil. Search. Wikipedia says that they used a weldable nickel
steel alloy.

Good question. They couldn't use titanium because they hadn't figured
out how to seam-weld it (we used electron-beam welding in a vacuum,
starting, I think, with the F-111).

Or the SR-71, as has been pointed out.


I don't know how they wound up joining it.

The Russians do have the capacity to forge an entire fighter airframe
from titanium, which eliminated the need to weld titanium.

In the US, I recall plans to have an entire factory with an argon
atmosphere (and people in spacesuits) to work titanium. Don't know
what happened though.

Titanium is pretty springy, with lots of spring-back. Don't know how
well titanium rivets work.


It would work nicely on a small boat, but it would be pretty tricky,
because epoxy bonding to aluminum is extremely weak unless the surface
is properly prepared. It also would depend on having plenty of overlap
at the joint.

Yes to all of it. I wasn't suggesting this approach here, but was
making the point about the necessity of stress spreading. For one
thing, one would need to drill all rivets and disassemble the boat, to
allow adequate surface prep. Apply goop and rivet back together, then
put in the autoclave and bake at 300F overnight. No autoclave? Hmm.
That is a problem. The airplane companies have all manner of
clamp-and-heat fixtures for this.

Yeah, but you can get over half the strength of A-B cure high-temp
epoxies with good room-temperature-cure material. That should be
plenty.

I did a lot of gluing for NASA as a summer employee in the late 1960s,
and we used 180 F (82 C). Higher is better, but many electronic
components could not tolerate soaking at 300 F for very long.


If it were me, I'd double-up on the rivets, then drill out the old
ones and replace them, too.

So we would end up with three times the number of rivets? That ought
to do it.

Hmmm. I meant double the number. I guess that was ambiguous.

Copy editor sought. Apply within.


I had such a Sears jon boat, back in the '60s. Mine was built by
Grumman. Sears used all kinds of suppliers, even including Fairchild
Aircraft.


Welding around the existing rivets won't fix an overstress problem.

Is the boat made of a weldable alloy?

FWIW, I think they all are. Most are made of 5052 or 5083/5086. Some
6061 is used for ribs, etc. All are weldable; the 5XXX series is more
common and more weldable.

My recollection was the same, that 5xxx series alloys were used, which
would make it weldable. But my sight-unseen guess would be that one
would do seam welds of the sheets to one another, and ignore the
rivets. This actually sounds like a good application of gas welding,
and was used to make airplanes in WW2. Though they used billions of
rivets too.

Joe Gwinn

It would be good for gas welding -- for someone who is really good at
it. I consider myself lucky to weld two aluminum tabs together;
without punching holes. But Kent White (the Tinman) has some great
info on it.

I bet welding is also pretty slow compared to riveting.

Joe Gwinn

On Mon, 01 Sep 2014 18:43:49 +0700, John B. Slocomb
wrote:

On Sun, 31 Aug 2014 20:40:09 -0400, Ed Huntress
wrote:

On Sun, 31 Aug 2014 16:25:36 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

Jerry Mayfield, who was an editor at AvWeek in the late '70s and early
'80s, and I used to compete to scoop each other on aerospace
manufacturing techniques (I was two floors below him, at American
Machinist). He had the advantage of being weekly, to my monthy, but I
beat him on single-crystal turbine blades and bismuth-alloy brazing .
g


I didn't know about the use for steel in automobiles. I am interested,
actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.



I wonder how the Russians built the MIG-25 fighters, which were made of
steel foil. Search. Wikipedia says that they used a weldable nickel
steel alloy.

Good question. They couldn't use titanium because they hadn't figured
out how to seam-weld it (we used electron-beam welding in a vacuum,
starting, I think, with the F-111).


I believe that the SR-71 came first :-)

I don't know how they wound up joining it.
SNIP
My brother and I went on a tour of the SR71 at the Boeing air and
space museum in Seattle. The man giving the tour was an ex SR71 pilot
and he had some great stories. One of the interesting things he told
us was that when building the first ones titanium was hard to get in
the USA. At least titanium of good enough quality to build an
airplane. So the CIA, who was having the plane built, bought titanium
from the Russians. They had to go through some pretty convoluted
channels to buy the titanium without the Russians knowing where it was
headed for and who was buying it. The pilot also told us how when
flying over the Soviet Union missles were fired at them and they
watched on radar as the missles tried to catch up and hit the plane
and then fall back to earth without ever hitting even one SR71. A
great tour, it lasted over an hour, and there were only about 15
people on the tour so it was real personal. Unfortunately the tour
didn't include us actually being able to sit in the plane. But it was
still one of the best tours I have ever experienced. We heard lots of
really interesting stuff, the tour guide was a good speaker and a good
raconteur.
Eric

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 12:07:57 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 16:25:36 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost
identical
that also had leaky rivets. I re-set all of the leaky rivets and
after
a few years some started to leak again. No surprise there. So with
the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much
stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

Jerry Mayfield, who was an editor at AvWeek in the late '70s and early
'80s, and [we] used to compete to scoop each other on aerospace
manufacturing techniques (I was two floors below him, at American
Machinist). He had the advantage of being weekly, to my monthy, but I
beat him on single-crystal turbine blades and bismuth-alloy brazing.
g

Not just for airplanes. I've seen aluminum brazing used to fabricate
aluminum heat sinks for water-cooled radar transmitter modules.

Right. furnace brazing is, or was, quite common in aluminum, and
automobile radiators have been some of the biggest users.

Ahh. I see from the following that you weren't talking about this kind
of brazing. I'll have to ask the mechanical guys what brazing alloys
were being used.


The bismuth-alloy technique is something different. It applies to
joining superalloys, such as Hastelloy, and the P&W job I watched it
being used on was for turbine-blade halves. It may work with other
alloys; I don't know.

The brazing foil is made of Hastelloy with a small amount of bismuth
added. The bismuth lowers the melting point; the objective in this
case is to drop it about 50 deg. F.

The parts and foil are placed in an oven at something like 10 deg. F
below the melting point of the parent metal. The foil melts and the
bismuth diffuses into the parent metal. As it does, the melting point
of the foil rises; the temperature is raised a few degrees; and the
joint solidifies at that temperature.

The bismuth has no significant effect on the melting point of the
parent metal. The finished joint has a melting temperature within
around 5 deg. F of the parent metal. The finished assembly is
virtually a solid piece with uniform metallurgy.

This is almost a kind of welding. I've seen the rough equivalent done
in the making of silver jewelry, where a series of silver brazing
allows with melting temperatures about 100 F apart are used so the
workpiece can be built up in stages. Also, it's well known that it
requires a higher temperature to un-braze a joint than the original
braze job, and jewelers depend on this difference.


I didn't know about the use for steel in automobiles. I am interested,
actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.

Thanks. I've printed the article out for reading.

I've read it. Very interesting.

Don't know how widely used in production this is, but the effect on
fatigue life is dramatic - from 10^4 cycles to 10^8 cycles. Although
not given is the effect of varying the number and arrangement of
spotwelds. Arrangement in particular is very important, and a circle
of welds is far better than a line.


Joe Gwinn

On Mon, 01 Sep 2014 13:03:15 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 12:07:57 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 16:25:36 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost
identical
that also had leaky rivets. I re-set all of the leaky rivets and
after
a few years some started to leak again. No surprise there. So with
the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much
stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

Jerry Mayfield, who was an editor at AvWeek in the late '70s and early
'80s, and [we] used to compete to scoop each other on aerospace
manufacturing techniques (I was two floors below him, at American
Machinist). He had the advantage of being weekly, to my monthy, but I
beat him on single-crystal turbine blades and bismuth-alloy brazing.
g

Not just for airplanes. I've seen aluminum brazing used to fabricate
aluminum heat sinks for water-cooled radar transmitter modules.

Right. furnace brazing is, or was, quite common in aluminum, and
automobile radiators have been some of the biggest users.

Ahh. I see from the following that you weren't talking about this kind
of brazing. I'll have to ask the mechanical guys what brazing alloys
were being used.


The bismuth-alloy technique is something different. It applies to
joining superalloys, such as Hastelloy, and the P&W job I watched it
being used on was for turbine-blade halves. It may work with other
alloys; I don't know.

The brazing foil is made of Hastelloy with a small amount of bismuth
added. The bismuth lowers the melting point; the objective in this
case is to drop it about 50 deg. F.

The parts and foil are placed in an oven at something like 10 deg. F
below the melting point of the parent metal. The foil melts and the
bismuth diffuses into the parent metal. As it does, the melting point
of the foil rises; the temperature is raised a few degrees; and the
joint solidifies at that temperature.

The bismuth has no significant effect on the melting point of the
parent metal. The finished joint has a melting temperature within
around 5 deg. F of the parent metal. The finished assembly is
virtually a solid piece with uniform metallurgy.

This is almost a kind of welding. I've seen the rough equivalent done
in the making of silver jewelry, where a series of silver brazing
allows with melting temperatures about 100 F apart are used so the
workpiece can be built up in stages. Also, it's well known that it
requires a higher temperature to un-braze a joint than the original
braze job, and jewelers depend on this difference.


I didn't know about the use for steel in automobiles. I am interested,
actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.

Thanks. I've printed the article out for reading.

I've read it. Very interesting.

Don't know how widely used in production this is, but the effect on
fatigue life is dramatic - from 10^4 cycles to 10^8 cycles. Although
not given is the effect of varying the number and arrangement of
spotwelds. Arrangement in particular is very important, and a circle
of welds is far better than a line.


Joe Gwinn

I think you're going to see some interesting developments in car
manufacturing over the next couple of years. Advanced high-strength
steels (AHSS) are taking over and welding them is difficult. Thus,
rivet-bonding and weld-bonding are being promoted as solutions.

Based on a preliminary look, it appears that the manufacturers are
also looking at laser welding for the new grades of steel. Some are
using it now and my guess is that they'll take over. At the same time,
direct-diode lasers are coming onto the market for welding and other
jobs.

My Associate Editor wrote a piece this month on direct-diode lasers:

http://www.nxtbook.com/nxtbooks/fabs...august2014/#/7

Tomorrow or Tuesday, our new magazine for lasers in manufacturing,
_Shop Floor Lasers_, will go live. The editor wrote an excellent piece
for the first issue on hybrid welding -- MIG plus laser -- and it's
amazing how deep but narrow those welds can be.

I don't have a URL for the magazine yet but here's the place-holder
homepage, which should have a link for the first issue by tomorrow or
Tuesday:

http://www.shopfloorlasers.com/

On 8/31/2014 1:05 PM, Ed Huntress wrote:
On Sun, 31 Aug 2014 13:37:34 -0400, Joe
wrote:

In ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky rivets.
In the past I had one of these boats, not a Sears but almost identical
that also had leaky rivets. I re-set all of the leaky rivets and after
a few years some started to leak again. No surprise there. So with the
boat I have now I'm thinking of MIG welding around all the rivets on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of water
this boat will be going in are small so even if the motor quits the
rowing distance will be short. Opinions?



If it's so old that the rivets are leaking you have more problems than
just leaky rivets.

Like metal fatigue - concentrated around the leaky rivets.

I would not even bother trying to weld or rivet.

Maybe coat the bottom with truck bed liner?

Or recycle it for aluminum scrap?

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 13:03:15 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 12:07:57 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 16:25:36 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky
rivets.
In the past I had one of these boats, not a Sears but almost
identical
that also had leaky rivets. I re-set all of the leaky rivets and
after
a few years some started to leak again. No surprise there. So with
the
boat I have now I'm thinking of MIG welding around all the rivets
on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of
water
this boat will be going in are small so even if the motor quits
the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much
stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

Jerry Mayfield, who was an editor at AvWeek in the late '70s and early
'80s, and [we] used to compete to scoop each other on aerospace
manufacturing techniques (I was two floors below him, at American
Machinist). He had the advantage of being weekly, to my monthy, but I
beat him on single-crystal turbine blades and bismuth-alloy brazing.
g

Not just for airplanes. I've seen aluminum brazing used to fabricate
aluminum heat sinks for water-cooled radar transmitter modules.

Right. furnace brazing is, or was, quite common in aluminum, and
automobile radiators have been some of the biggest users.

Ahh. I see from the following that you weren't talking about this kind
of brazing. I'll have to ask the mechanical guys what brazing alloys
were being used.


The bismuth-alloy technique is something different. It applies to
joining superalloys, such as Hastelloy, and the P&W job I watched it
being used on was for turbine-blade halves. It may work with other
alloys; I don't know.

The brazing foil is made of Hastelloy with a small amount of bismuth
added. The bismuth lowers the melting point; the objective in this
case is to drop it about 50 deg. F.

The parts and foil are placed in an oven at something like 10 deg. F
below the melting point of the parent metal. The foil melts and the
bismuth diffuses into the parent metal. As it does, the melting point
of the foil rises; the temperature is raised a few degrees; and the
joint solidifies at that temperature.

The bismuth has no significant effect on the melting point of the
parent metal. The finished joint has a melting temperature within
around 5 deg. F of the parent metal. The finished assembly is
virtually a solid piece with uniform metallurgy.

This is almost a kind of welding. I've seen the rough equivalent done
in the making of silver jewelry, where a series of silver brazing
allows with melting temperatures about 100 F apart are used so the
workpiece can be built up in stages. Also, it's well known that it
requires a higher temperature to un-braze a joint than the original
braze job, and jewelers depend on this difference.


I didn't know about the use for steel in automobiles. I am interested,
actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.

Thanks. I've printed the article out for reading.

I've read it. Very interesting.

Don't know how widely used in production this is, but the effect on
fatigue life is dramatic - from 10^4 cycles to 10^8 cycles. Although
not given is the effect of varying the number and arrangement of
spotwelds. Arrangement in particular is very important, and a circle
of welds is far better than a line.


Joe Gwinn

I think you're going to see some interesting developments in car
manufacturing over the next couple of years. Advanced high-strength
steels (AHSS) are taking over and welding them is difficult. Thus,
rivet-bonding and weld-bonding are being promoted as solutions.

The article mentioned clinching, and it tested as slightly better than
welding in fatigue life. One assumes that rivets will be at least that
good.


Based on a preliminary look, it appears that the manufacturers are
also looking at laser welding for the new grades of steel. Some are
using it now and my guess is that they'll take over. At the same time,
direct-diode lasers are coming onto the market for welding and other
jobs.

But how does this help if the alloy isn't weldable, with welds becoming
brittle?


My Associate Editor wrote a piece this month on direct-diode lasers:

http://www.nxtbook.com/nxtbooks/fabshopmagdirect/august2014/#/7

Tomorrow or Tuesday, our new magazine for lasers in manufacturing,
_Shop Floor Lasers_, will go live. The editor wrote an excellent piece
for the first issue on hybrid welding -- MIG plus laser -- and it's
amazing how deep but narrow those welds can be.

I don't have a URL for the magazine yet but here's the place-holder
homepage, which should have a link for the first issue by tomorrow or
Tuesday:

http://www.shopfloorlasers.com/

Deep but narrow welds can fracture easily. There was an military
airplane crash that was traced to an electron-beam plug weld being used
to prevent rotation of two forged components that were screwed
together, this component being flight critical. Weld cracked, parts
unscrewed, control was lost, aircraft was lost.

Don't know if this applies to cars, but the story popped up on the
mention of deep narrow welds.

Joe Gwinn

On Mon, 01 Sep 2014 15:43:25 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 13:03:15 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 12:07:57 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 16:25:36 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Sun, 31 Aug 2014 13:37:34 -0400, Joe Gwinn
wrote:

In article ,
wrote:

I have an old Jon boat, from Sears, that has a bunch of leaky
rivets.
In the past I had one of these boats, not a Sears but almost
identical
that also had leaky rivets. I re-set all of the leaky rivets and
after
a few years some started to leak again. No surprise there. So with
the
boat I have now I'm thinking of MIG welding around all the rivets
on
the outside of the boat and then running some beads on the inside
bracing because some of the rivets will be loose. I know the welds
will add some drag but I really don't care, the only bodies of
water
this boat will be going in are small so even if the motor quits
the
rowing distance will be short. Opinions?

It sounds like there are too few rivets, each carrying too much
stress.
Is there room for more rivets?

Airplanes are built with a combination of high-temp-cure epoxy and
rivets, precisely to spread the stresses out.

This is a tricky one. That's not really how aircraft rivet-bonding
works (the rivets are there only to prevent lifting of the edges, and
resulting failure in cleavage and peel), although that *is* how
rivet-bonding of high-strength steel works, in modern automobile
assembly and repair. We can discuss this if you're interested.

I did know the roles of glue and rivets in airplane manufacture. (I
have been reading Aviation Week for since I was 13 - my father
subscribed.)

Jerry Mayfield, who was an editor at AvWeek in the late '70s and early
'80s, and [we] used to compete to scoop each other on aerospace
manufacturing techniques (I was two floors below him, at American
Machinist). He had the advantage of being weekly, to my monthy, but I
beat him on single-crystal turbine blades and bismuth-alloy brazing.
g

Not just for airplanes. I've seen aluminum brazing used to fabricate
aluminum heat sinks for water-cooled radar transmitter modules.

Right. furnace brazing is, or was, quite common in aluminum, and
automobile radiators have been some of the biggest users.

Ahh. I see from the following that you weren't talking about this kind
of brazing. I'll have to ask the mechanical guys what brazing alloys
were being used.


The bismuth-alloy technique is something different. It applies to
joining superalloys, such as Hastelloy, and the P&W job I watched it
being used on was for turbine-blade halves. It may work with other
alloys; I don't know.

The brazing foil is made of Hastelloy with a small amount of bismuth
added. The bismuth lowers the melting point; the objective in this
case is to drop it about 50 deg. F.

The parts and foil are placed in an oven at something like 10 deg. F
below the melting point of the parent metal. The foil melts and the
bismuth diffuses into the parent metal. As it does, the melting point
of the foil rises; the temperature is raised a few degrees; and the
joint solidifies at that temperature.

The bismuth has no significant effect on the melting point of the
parent metal. The finished joint has a melting temperature within
around 5 deg. F of the parent metal. The finished assembly is
virtually a solid piece with uniform metallurgy.

This is almost a kind of welding. I've seen the rough equivalent done
in the making of silver jewelry, where a series of silver brazing
allows with melting temperatures about 100 F apart are used so the
workpiece can be built up in stages. Also, it's well known that it
requires a higher temperature to un-braze a joint than the original
braze job, and jewelers depend on this difference.


I didn't know about the use for steel in automobiles. I am interested,
actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.

Thanks. I've printed the article out for reading.

I've read it. Very interesting.

Don't know how widely used in production this is, but the effect on
fatigue life is dramatic - from 10^4 cycles to 10^8 cycles. Although
not given is the effect of varying the number and arrangement of
spotwelds. Arrangement in particular is very important, and a circle
of welds is far better than a line.


Joe Gwinn

I think you're going to see some interesting developments in car
manufacturing over the next couple of years. Advanced high-strength
steels (AHSS) are taking over and welding them is difficult. Thus,
rivet-bonding and weld-bonding are being promoted as solutions.

The article mentioned clinching, and it tested as slightly better than
welding in fatigue life. One assumes that rivets will be at least that
good.


Based on a preliminary look, it appears that the manufacturers are
also looking at laser welding for the new grades of steel. Some are
using it now and my guess is that they'll take over. At the same time,
direct-diode lasers are coming onto the market for welding and other
jobs.

But how does this help if the alloy isn't weldable, with welds becoming
brittle?

Lasers produce a much smaller heat-affected zone, and some other
parameters are quite different from those produced by arc welding.

Here is some info. Note that there are many different types of AHSS,
which have quite different properties:

http://tinyurl.com/oznv84u

I haven't explored fatigue properties, but I'm leaving that alone for
now and leaving it to the editors of Shop Floor Lasers. I'm listed on
the masthead but I'm actually not going to do much with it.




My Associate Editor wrote a piece this month on direct-diode lasers:

http://www.nxtbook.com/nxtbooks/fabshopmagdirect/august2014/#/7

Tomorrow or Tuesday, our new magazine for lasers in manufacturing,
_Shop Floor Lasers_, will go live. The editor wrote an excellent piece
for the first issue on hybrid welding -- MIG plus laser -- and it's
amazing how deep but narrow those welds can be.

I don't have a URL for the magazine yet but here's the place-holder
homepage, which should have a link for the first issue by tomorrow or
Tuesday:

http://www.shopfloorlasers.com/

Deep but narrow welds can fracture easily. There was an military
airplane crash that was traced to an electron-beam plug weld being used
to prevent rotation of two forged components that were screwed
together, this component being flight critical. Weld cracked, parts
unscrewed, control was lost, aircraft was lost.

Don't know if this applies to cars, but the story popped up on the
mention of deep narrow welds.

Joe Gwinn

Well, the welding scene is changing a great deal. I'll know more in
February or so. We have another new magazine on the way. d8-)

--
Ed Huntress

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 15:43:25 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 13:03:15 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

[snip]

The parts and foil are placed in an oven at something like 10 deg. F
below the melting point of the parent metal. The foil melts and the
bismuth diffuses into the parent metal. As it does, the melting point
of the foil rises; the temperature is raised a few degrees; and the
joint solidifies at that temperature.

The bismuth has no significant effect on the melting point of the
parent metal. The finished joint has a melting temperature within
around 5 deg. F of the parent metal. The finished assembly is
virtually a solid piece with uniform metallurgy.

This is almost a kind of welding. I've seen the rough equivalent done
in the making of silver jewelry, where a series of silver brazing
allows with melting temperatures about 100 F apart are used so the
workpiece can be built up in stages. Also, it's well known that it
requires a higher temperature to un-braze a joint than the original
braze job, and jewelers depend on this difference.


I didn't know about the use for steel in automobiles. I am
interested, actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.

Thanks. I've printed the article out for reading.

I've read it. Very interesting.

Don't know how widely used in production this is, but the effect on
fatigue life is dramatic - from 10^4 cycles to 10^8 cycles. Although
not given is the effect of varying the number and arrangement of
spotwelds. Arrangement in particular is very important, and a circle
of welds is far better than a line.


Joe Gwinn

I think you're going to see some interesting developments in car
manufacturing over the next couple of years. Advanced high-strength
steels (AHSS) are taking over and welding them is difficult. Thus,
rivet-bonding and weld-bonding are being promoted as solutions.

The article mentioned clinching, and it tested as slightly better than
welding in fatigue life. One assumes that rivets will be at least that
good.


Based on a preliminary look, it appears that the manufacturers are
also looking at laser welding for the new grades of steel. Some are
using it now and my guess is that they'll take over. At the same time,
direct-diode lasers are coming onto the market for welding and other
jobs.

But how does this help if the alloy isn't weldable, with welds becoming
brittle?

Lasers produce a much smaller heat-affected zone, and some other
parameters are quite different from those produced by arc welding.

Here is some info. Note that there are many different types of AHSS,
which have quite different properties:

http://tinyurl.com/oznv84u

I haven't explored fatigue properties, but I'm leaving that alone for
now and leaving it to the editors of Shop Floor Lasers. I'm listed on
the masthead but I'm actually not going to do much with it.

Interesting. While they didn't mention fatigue properties, they did
mention the the stronger the steel the weaker the weld, so there may be
an issue here. Thus, rivets.


My Associate Editor wrote a piece this month on direct-diode lasers:

http://www.nxtbook.com/nxtbooks/fabshopmagdirect/august2014/#/7

Tomorrow or Tuesday, our new magazine for lasers in manufacturing,
_Shop Floor Lasers_, will go live. The editor wrote an excellent piece
for the first issue on hybrid welding -- MIG plus laser -- and it's
amazing how deep but narrow those welds can be.

I don't have a URL for the magazine yet but here's the place-holder
homepage, which should have a link for the first issue by tomorrow or
Tuesday:

http://www.shopfloorlasers.com/

Deep but narrow welds can fracture easily. There was an military
airplane crash that was traced to an electron-beam plug weld being used
to prevent rotation of two forged components that were screwed
together, this component being flight critical. Weld cracked, parts
unscrewed, control was lost, aircraft was lost.

Don't know if this applies to cars, but the story popped up on the
mention of deep narrow welds.

Joe Gwinn

Well, the welding scene is changing a great deal. I'll know more in
February or so. We have another new magazine on the way. d8-)

I think the issue was that the plug area wasn't large enough, and I'd
bet that the mating parts were able to wiggle just enough to fatigue
the weld metal, which was probably in the as-quenched state. Maybe if
the welded assembly had been heat treated it would have been OK, but
nobody was interested after the crash, and that part was made as a
single forging thereafter.

When does welding fatigue set in? I mean of editors.


Joe Gwinn

On Mon, 01 Sep 2014 18:43:30 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 15:43:25 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

On Mon, 01 Sep 2014 13:03:15 -0400, Joe Gwinn
wrote:

In article , Ed Huntress
wrote:

[snip]

The parts and foil are placed in an oven at something like 10 deg. F
below the melting point of the parent metal. The foil melts and the
bismuth diffuses into the parent metal. As it does, the melting point
of the foil rises; the temperature is raised a few degrees; and the
joint solidifies at that temperature.

The bismuth has no significant effect on the melting point of the
parent metal. The finished joint has a melting temperature within
around 5 deg. F of the parent metal. The finished assembly is
virtually a solid piece with uniform metallurgy.

This is almost a kind of welding. I've seen the rough equivalent done
in the making of silver jewelry, where a series of silver brazing
allows with melting temperatures about 100 F apart are used so the
workpiece can be built up in stages. Also, it's well known that it
requires a higher temperature to un-braze a joint than the original
braze job, and jewelers depend on this difference.


I didn't know about the use for steel in automobiles. I am
interested, actually.

Try this for a starter:

http://tinyurl.com/pqerf8n

They're trying to avoid working and loosening the rivets -- quite
different from the objective in aircraft.

Thanks. I've printed the article out for reading.

I've read it. Very interesting.

Don't know how widely used in production this is, but the effect on
fatigue life is dramatic - from 10^4 cycles to 10^8 cycles. Although
not given is the effect of varying the number and arrangement of
spotwelds. Arrangement in particular is very important, and a circle
of welds is far better than a line.


Joe Gwinn

I think you're going to see some interesting developments in car
manufacturing over the next couple of years. Advanced high-strength
steels (AHSS) are taking over and welding them is difficult. Thus,
rivet-bonding and weld-bonding are being promoted as solutions.

The article mentioned clinching, and it tested as slightly better than
welding in fatigue life. One assumes that rivets will be at least that
good.


Based on a preliminary look, it appears that the manufacturers are
also looking at laser welding for the new grades of steel. Some are
using it now and my guess is that they'll take over. At the same time,
direct-diode lasers are coming onto the market for welding and other
jobs.

But how does this help if the alloy isn't weldable, with welds becoming
brittle?

Lasers produce a much smaller heat-affected zone, and some other
parameters are quite different from those produced by arc welding.

Here is some info. Note that there are many different types of AHSS,
which have quite different properties:

http://tinyurl.com/oznv84u

I haven't explored fatigue properties, but I'm leaving that alone for
now and leaving it to the editors of Shop Floor Lasers. I'm listed on
the masthead but I'm actually not going to do much with it.

Interesting. While they didn't mention fatigue properties, they did
mention the the stronger the steel the weaker the weld, so there may be
an issue here. Thus, rivets.


My Associate Editor wrote a piece this month on direct-diode lasers:

http://www.nxtbook.com/nxtbooks/fabshopmagdirect/august2014/#/7

Tomorrow or Tuesday, our new magazine for lasers in manufacturing,
_Shop Floor Lasers_, will go live. The editor wrote an excellent piece
for the first issue on hybrid welding -- MIG plus laser -- and it's
amazing how deep but narrow those welds can be.

I don't have a URL for the magazine yet but here's the place-holder
homepage, which should have a link for the first issue by tomorrow or
Tuesday:

http://www.shopfloorlasers.com/

Deep but narrow welds can fracture easily. There was an military
airplane crash that was traced to an electron-beam plug weld being used
to prevent rotation of two forged components that were screwed
together, this component being flight critical. Weld cracked, parts
unscrewed, control was lost, aircraft was lost.

Don't know if this applies to cars, but the story popped up on the
mention of deep narrow welds.

Joe Gwinn

Well, the welding scene is changing a great deal. I'll know more in
February or so. We have another new magazine on the way. d8-)

I think the issue was that the plug area wasn't large enough, and I'd
bet that the mating parts were able to wiggle just enough to fatigue
the weld metal, which was probably in the as-quenched state. Maybe if
the welded assembly had been heat treated it would have been OK, but
nobody was interested after the crash, and that part was made as a
single forging thereafter.

When does welding fatigue set in? I mean of editors.

LOL! I guess it depends on how curious one is. If you aren't
obsessively curious, it's not a good career. If you are obsessively
curious, it's one of the best.

--
Ed Huntress




Joe Gwinn