My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

Karl

On Dec 7, 10:00*am, "Karl Townsend"
wrote:
My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

If you heat them up with a blowtorch, you might manage to undo the
bolts without damaging the thread. Sometimes heat can work wonders on
rusty fasteners.

Best wishes,

Chris

If you heat them up with a blowtorch, you might manage to undo the
bolts without damaging the thread. Sometimes heat can work wonders on
rusty fasteners.

I've had good luck with this with steel on steel. But I had a bunch of
steel pipe in Al fittings a while back. This idea failed nearly every time.

Karl

Karl Townsend wrote:
If you heat them up with a blowtorch, you might manage to undo the
bolts without damaging the thread. Sometimes heat can work wonders on
rusty fasteners.

I've had good luck with this with steel on steel. But I had a bunch
of steel pipe in Al fittings a while back. This idea failed nearly
every time.
Karl

Heat 'em up , and hold an ice cube on the bolt . That's worked for me .
--
Snag
sometimes ya gotta
shovel manure
to pay the bills

On Sun, 7 Dec 2008 06:33:04 -0600, the infamous "Terry Coombs"
scrawled the following:

Karl Townsend wrote:
If you heat them up with a blowtorch, you might manage to undo the
bolts without damaging the thread. Sometimes heat can work wonders on
rusty fasteners.

I've had good luck with this with steel on steel. But I had a bunch
of steel pipe in Al fittings a while back. This idea failed nearly
every time.
Karl

Heat 'em up , and hold an ice cube on the bolt . That's worked for me .

We used to use inverted cans of freon for spot chilling. The Greenies
would **** a brick about that today, not to mention the cost of R-12
nowadays.

--
At current market valuations (GM is worth less than Mattel)
the Chinese government can afford to buy GM with petty cash.
--Bertel Shmitt on kencan7 blogspot

Karl,
Saving the threads, even if it were possible is a waste of time, because the
treads have become aluminum oxide and have no residual strength anyway. Next
time use anti-sieze at assembly. Most likely the fault was electrolysis, as
they were probably diecast and zinc is often alloyed with the aluminum to
promote flow in the mold. In the presence of water, the unit becomes
thousands of little batteries.
Steve

"Karl Townsend" wrote in message
anews.com...
My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

Karl

Saving the threads, even if it were possible is a waste of time, because
the
treads have become aluminum oxide and have no residual strength anyway.
Next time use anti-sieze at assembly. Most likely the fault was
electrolysis, as they were probably diecast and zinc is often alloyed with
the aluminum to promote flow in the mold. In the presence of water, the
unit becomes thousands of little batteries.

On second inspection; if I can't get the bolts out, it looks like drilling
the next size and tapping won't work. I'll have to make all new. My version
will be a bit beefier. What's the best bolt for AL with an eye on
electrolysis? AL bolts are too soft in small sizes. Is stainless a good
choice? or maybe brass?

Karl

Karl Townsend wrote:

Saving the threads, even if it were possible is a waste of time, because
the
treads have become aluminum oxide and have no residual strength anyway.
Next time use anti-sieze at assembly. Most likely the fault was
electrolysis, as they were probably diecast and zinc is often alloyed with
the aluminum to promote flow in the mold. In the presence of water, the
unit becomes thousands of little batteries.


On second inspection; if I can't get the bolts out, it looks like drilling
the next size and tapping won't work. I'll have to make all new. My version
will be a bit beefier. What's the best bolt for AL with an eye on
electrolysis? AL bolts are too soft in small sizes. Is stainless a good
choice? or maybe brass?

Karl


Any alloy with significant copper in contact with it is bad news and
will cause accelerated corrosion of the aluminium. Stainless is
probably the least bad choice but even that is prone to seizing.

http://www.engineersedge.com/galvanic_capatability.htm

Saving the threads, even if it were possible is a waste of time, because
the
treads have become aluminum oxide and have no residual strength anyway.
Next time use anti-sieze at assembly. Most likely the fault was
electrolysis, as they were probably diecast and zinc is often alloyed with
the aluminum to promote flow in the mold. In the presence of water, the
unit becomes thousands of little batteries.

On second inspection; if I can't get the bolts out, it looks like drilling
the next size and tapping won't work. I'll have to make all new. My version
will be a bit beefier. What's the best bolt for AL with an eye on
electrolysis? AL bolts are too soft in small sizes. Is stainless a good
choice? or maybe brass?

Karl

Karl,
I run into this all the time.. .. .. and I've found out that the best
solution (if you have the room) is to drill, tap and install a
stainless Helicoil. A bit pricey, but ya only do it once.
Ken.

On Sun, 07 Dec 2008 09:08:56 -0500, Ken Sterling
wrote:


Saving the threads, even if it were possible is a waste of time, because
the
treads have become aluminum oxide and have no residual strength anyway.
Next time use anti-sieze at assembly. Most likely the fault was
electrolysis, as they were probably diecast and zinc is often alloyed with
the aluminum to promote flow in the mold. In the presence of water, the
unit becomes thousands of little batteries.

On second inspection; if I can't get the bolts out, it looks like drilling
the next size and tapping won't work. I'll have to make all new. My version
will be a bit beefier. What's the best bolt for AL with an eye on
electrolysis? AL bolts are too soft in small sizes. Is stainless a good
choice? or maybe brass?

Karl

Karl,
I run into this all the time.. .. .. and I've found out that the best
solution (if you have the room) is to drill, tap and install a
stainless Helicoil. A bit pricey, but ya only do it once.
Ken.

Second that. I design a lot of aluminum heater blocks, etc. at work,
and always specify stainless helicoils. Works great. I do the same
at home. The 1/4"-20 tpi helicoiled holes in my flush kit clamp have
been in a marine environment (dock box) for 3 yrs. and work fine.
http://metalworking.com/dropbox/FlushKitClamp09.jpg

Pete Keillor

On Sun, 07 Dec 2008 09:08:56 -0500, Ken Sterling wrote:


Saving the threads, even if it were possible is a waste of time,
because the
treads have become aluminum oxide and have no residual strength
anyway. Next time use anti-sieze at assembly. Most likely the fault
was electrolysis, as they were probably diecast and zinc is often
alloyed with the aluminum to promote flow in the mold. In the presence
of water, the unit becomes thousands of little batteries.

On second inspection; if I can't get the bolts out, it looks like
drilling the next size and tapping won't work. I'll have to make all
new. My version will be a bit beefier. What's the best bolt for AL with
an eye on electrolysis? AL bolts are too soft in small sizes. Is
stainless a good choice? or maybe brass?

Karl

Karl,
I run into this all the time.. .. .. and I've found out that the best
solution (if you have the room) is to drill, tap and install a stainless
Helicoil. A bit pricey, but ya only do it once. Ken.

One of my clients (aerospace) uses Kingserts almost exclusively for this,
with great success. I have no clue how much more expensive they are than
Helicoil, but they look a lot stouter.

BUT, anything that's going to be exposed to real weather gets stainless
to stainless (and lots of anti-seize on assembly).

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

On Dec 7, 3:05*pm, Tim Wescott wrote:
On Sun, 07 Dec 2008 09:08:56 -0500, Ken Sterling wrote:
Saving the threads, even if it were possible is a waste of time,
because the
treads have become aluminum oxide and have no residual strength
anyway. Next time use anti-sieze at assembly. Most likely the fault
was electrolysis, as they were probably diecast and zinc is often
alloyed with the aluminum to promote flow in the mold. In the presence
of water, the unit becomes thousands of little batteries.

On second inspection; if I can't get the bolts out, it looks like
drilling the next size and tapping won't work. I'll have to make all
new. *My version will be a bit beefier. What's the best bolt for AL with
an eye on electrolysis? AL bolts are too soft in small sizes. Is
stainless a good choice? or maybe brass?

Karl

Karl,
I run into this all the time.. .. .. and I've found out that the best
solution (if you have the room) is to drill, tap and install a stainless
Helicoil. *A bit pricey, but ya only do it once. Ken.

One of my clients (aerospace) uses Kingserts almost exclusively for this,
with great success. *I have no clue how much more expensive they are than
Helicoil, but they look a lot stouter.

BUT, anything that's going to be exposed to real weather gets stainless
to stainless (and lots of anti-seize on assembly).

--
Tim Wescott
Control systems and communications consultinghttp://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes,http://www.wescottdesign.com/actfes/actfes.html

Any bolt I remove or replace on my 15 year old RX-7 gets a coating of
Nickel Neverseize prior to replacement. Do not use the copper based
anti-seize compounds with aluminum or diecast materials.

General purpose stainless steel fasteners are a lousy proposition
because they are too soft and gall easily. I have used high tensile
stainless steel studs on exhaust systems but these are pricey.

For your application I'd use helicoils as suggested above and plated
grade 5 bolts, along with a coating of Nickel anti-seize compound.

Wolfgang

On 2008-12-07, Tim Wescott wrote:

[ ... ]

One of my clients (aerospace) uses Kingserts almost exclusively for this,
with great success. I have no clue how much more expensive they are than
Helicoil, but they look a lot stouter.

"Kingserts"? I'm not familiar with them, but I am familiar with
"Keyserts" -- threaded OD (different pitch than the ID, unlike a
Helicoil) which screws into a tapped hole, then a special tool drives
two or four projections down through the threads in the metal block
(there are already grooves for the threads in the Keysert), thus locking
it into place.

I've seen them advertised in stainless, and I've used some small
ones in a metal which looks like zinc plated steel -- the ones which I
have are all nearly black, though I don't know what they looked like
when new.

They do require a larger tapped hole because of the different
thread pitch on the OD from what is accepted on the ID.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Tim Wescott wrote:
On Sun, 07 Dec 2008 09:08:56 -0500, Ken Sterling wrote:



One of my clients (aerospace) uses Kingserts almost exclusively for this,
with great success.




That would be "Keensert"...

Pictures here;

http://www.thorintl.com/Keenserts-Ke...ng-Inserts.htm

Install data here light duty/heavy duty;

http://www.barnhillbolt.com/specs/In...ghtInserts.htm

http://www.barnhillbolt.com/specs/In...utyInserts.htm

Matt

Karl Townsend wrote:

Saving the threads, even if it were possible is a waste of time, because
the
treads have become aluminum oxide and have no residual strength anyway.
Next time use anti-sieze at assembly. Most likely the fault was
electrolysis, as they were probably diecast and zinc is often alloyed with
the aluminum to promote flow in the mold. In the presence of water, the
unit becomes thousands of little batteries.

On second inspection; if I can't get the bolts out, it looks like drilling
the next size and tapping won't work. I'll have to make all new. My version
will be a bit beefier. What's the best bolt for AL with an eye on
electrolysis? AL bolts are too soft in small sizes. Is stainless a good
choice? or maybe brass?

Karl

A through bolt and nylock nut in the material of your choice, sleeved in
a plastic tube and with plastic washers under the metal ones on each
side? No dissimilar threads to corrode.

"Karl Townsend" writes:

Saving the threads, even if it were possible is a waste of time, because
the
treads have become aluminum oxide and have no residual strength anyway.
Next time use anti-sieze at assembly. Most likely the fault was
electrolysis, as they were probably diecast and zinc is often alloyed with
the aluminum to promote flow in the mold. In the presence of water, the
unit becomes thousands of little batteries.

On second inspection; if I can't get the bolts out, it looks like drilling
the next size and tapping won't work. I'll have to make all new. My version
will be a bit beefier. What's the best bolt for AL with an eye on
electrolysis? AL bolts are too soft in small sizes. Is stainless a good
choice? or maybe brass?

Won't work why? If it's because you can't go up a size, I'll give a
hearty "me too" on the heli-coils.

"Joe Pfeiffer" wrote in message
"Karl Townsend" writes:

Saving the threads, even if it were possible is a waste
of time, because
the
treads have become aluminum oxide and have no residual
strength anyway.
Next time use anti-sieze at assembly. Most likely the
fault was
electrolysis, as they were probably diecast and zinc is
often alloyed with
the aluminum to promote flow in the mold. In the
presence of water, the
unit becomes thousands of little batteries.

On second inspection; if I can't get the bolts out, it
looks like drilling
the next size and tapping won't work. I'll have to make
all new. My version
will be a bit beefier. What's the best bolt for AL with
an eye on
electrolysis? AL bolts are too soft in small sizes. Is
stainless a good
choice? or maybe brass?

Won't work why? If it's because you can't go up a size,
I'll give a
hearty "me too" on the heli-coils.

Naw, heli-coils won't work. If the next larger size thread
is too much
then so is the o.d. of a h-c!
phil

"Phil Kangas" writes:

"Joe Pfeiffer" wrote in message

Won't work why? If it's because you can't go up a size,
I'll give a
hearty "me too" on the heli-coils.

Naw, heli-coils won't work. If the next larger size thread
is too much
then so is the o.d. of a h-c!

Depends on why he can't go up a size -- if it's a limit in the
aluminum piece you're right, but I'm having a hard time thinking of a
scenario for that. If it's something like the size of the head in the
piece that bolts to it, or some wonky hand-turn wingbolt he can't find
in another size.....

"Karl Townsend" wrote in message
anews.com...

Saving the threads, even if it were possible is a waste of time, because
the
treads have become aluminum oxide and have no residual strength anyway.
Next time use anti-sieze at assembly. Most likely the fault was
electrolysis, as they were probably diecast and zinc is often alloyed
with the aluminum to promote flow in the mold. In the presence of water,
the unit becomes thousands of little batteries.

On second inspection; if I can't get the bolts out, it looks like drilling
the next size and tapping won't work. I'll have to make all new. My
version will be a bit beefier. What's the best bolt for AL with an eye on
electrolysis? AL bolts are too soft in small sizes. Is stainless a good
choice? or maybe brass?

Karl

Stainless is worse than ordinary steel for causing electrolytic corrosion,
you need a metal with a valency closer to AL - brass is near, but any AL
based alloy will be best.

On Sun, 7 Dec 2008 13:18:55 +0100, "Steve Lusardi"
wrote:

Karl,
Saving the threads, even if it were possible is a waste of time, because the
treads have become aluminum oxide and have no residual strength anyway. Next
time use anti-sieze at assembly. Most likely the fault was electrolysis, as
they were probably diecast and zinc is often alloyed with the aluminum to
promote flow in the mold. In the presence of water, the unit becomes
thousands of little batteries.

Is there something unique about diecasting alloys that make them prone
to becoming "thousands of little batteries?" Leaded red brass
(85-5-5-5; copper-tin-lead-zinc) is very durable in sea water, and is
composed of metals much more widely separated on the galvanic series
than aluminum and zinc, which are quite close to one another.

--
Ned Simmons

Ned Simmons writes:

On Sun, 7 Dec 2008 13:18:55 +0100, "Steve Lusardi"
wrote:

Karl,
Saving the threads, even if it were possible is a waste of time, because the
treads have become aluminum oxide and have no residual strength anyway. Next
time use anti-sieze at assembly. Most likely the fault was electrolysis, as
they were probably diecast and zinc is often alloyed with the aluminum to
promote flow in the mold. In the presence of water, the unit becomes
thousands of little batteries.

Is there something unique about diecasting alloys that make them prone
to becoming "thousands of little batteries?" Leaded red brass
(85-5-5-5; copper-tin-lead-zinc) is very durable in sea water, and is
composed of metals much more widely separated on the galvanic series
than aluminum and zinc, which are quite close to one another.

It isn't the zinc in the aluminum alloy, it's that the zinc in the
alloy is in contact with the steel bolts.

On Sun, 07 Dec 2008 15:39:36 -0700, Joe Pfeiffer
wrote:

Ned Simmons writes:

On Sun, 7 Dec 2008 13:18:55 +0100, "Steve Lusardi"
wrote:

Karl,
Saving the threads, even if it were possible is a waste of time, because the
treads have become aluminum oxide and have no residual strength anyway. Next
time use anti-sieze at assembly. Most likely the fault was electrolysis, as
they were probably diecast and zinc is often alloyed with the aluminum to
promote flow in the mold. In the presence of water, the unit becomes
thousands of little batteries.

Is there something unique about diecasting alloys that make them prone
to becoming "thousands of little batteries?" Leaded red brass
(85-5-5-5; copper-tin-lead-zinc) is very durable in sea water, and is
composed of metals much more widely separated on the galvanic series
than aluminum and zinc, which are quite close to one another.

It isn't the zinc in the aluminum alloy, it's that the zinc in the
alloy is in contact with the steel bolts.

Maybe I'm misunderstanding what Steve is saying, but I don't see how a
lump of aluminum alloy and and a bolt would become "thousands of
little batteries." I took that to mean that the zinc and aluminum are
finely segregated, and not truly alloyed.

But if you've got the right interpretation, I doubt there's enough
difference between the galvanic potentials of aluminum, zinc, and
aluminum die casting alloy to make much difference in the case at
hand.

--
Ned Simmons

"Karl Townsend" wrote in message
anews.com...
My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

Karl


Karl
You work way too cheap. I would get new clamps. Ebay Item number:
300275218359 I have had these for 6-7 years without a problem.
Steve

You work way too cheap. I would get new clamps. Ebay Item number:
300275218359 I have had these for 6-7 years without a problem.
Steve

you're right, and if they were mine, that's what i would do. "The Kid" and I
trade favors. But he don't buy for me and I don't buy for him. So, when he
asks for me to fix something, I fix it. I'm going to helicoil for him. he
buys the coils.

karl

On Sun, 7 Dec 2008 12:33:30 -0600, "Karl Townsend"
wrote:



You work way too cheap. I would get new clamps. Ebay Item number:
300275218359 I have had these for 6-7 years without a problem.
Steve

you're right, and if they were mine, that's what i would do. "The Kid" and I
trade favors. But he don't buy for me and I don't buy for him. So, when he
asks for me to fix something, I fix it. I'm going to helicoil for him. he
buys the coils.

karl

I have two sons so I understand your logic. But I wouldn't screw
around with helicoils. I'd silverbraze sheetmetal tabs to steel nuts,
assemble the clamp, hammer the tabs around the bottom of the clamp so
the nut can't turn, disassemble and give the modified nuts an hour in
the zinc bucket. (Hardware store bolts are more like 10 minutes' worth
of zinc.) Stainless bolts, nuts and tabs could skip the zinc.

I've used clamps very much like these with zinc-plated bolts, no
problems. Use of antisieze or silicone is certainly a good idea,
though I didn't and got away with it. These clamps shouldn't get wet
from rain or road spray when used to secure a topper or tonneau cover.
Non-copper-based anti-sieze is handy stuff anyway. I use it routinely
on light bulb bases since bulb bases and sockets started being made of
aluminum rather than brass. I've not had one stuck bulb since I
started doing that years ago.

On Sun, 7 Dec 2008 04:00:47 -0600, "Karl Townsend"
wrote:

My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

Karl



Cut the tops of the bolts. drill as much out as possible, build a dam around
the rest and dissolve out with diluted nitric acid.

Takes out the steel and cleans up the aluminium.

When re-assembling, wrap PTFE tape around the bolt threads, lessens the
corrosion and aids disassembly. Alternatively, use low strength Loctite to
seal the threads from corrosion.

Mark Rand
RTFM

"Karl Townsend" wrote in message
anews.com...
My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

The very first non-invasive step:

Kroil, PB Blaster.

Then, the other stuff. Nitric acid could work, as well, altho I never had
luck. But it might do enough around the edges of the thread to free it up.
--
PV'd




Karl

"Karl Townsend" wrote in message
anews.com...
My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

Karl



After you remedy the corrosion problem, consider the use of some silicone
for preventing water or condensation from becoming the electrolyte
contributing to the mischief.

--
Roger Shoaf
If you are not part of the solution, you are not dissolved in the solvent.

The seized screws are less of a problem or fault, as they are a feature,
IMO.

I would assume most truck owners that have bed caps don't intend to be
removing the cap regularlly, and want an inexpensive mounting device so they
don't have to drill holes in the bed sides.

The manufacturer wasn't trying to build an infinite life product (at the
original price) for various reasons.

When the steel seizes in the aluminum bracket it somewhat insures that the
mounting is secure. If the screws could loosen from vibration or getting
bumped while loading materials in the bed, the cap could potentially
separate from the bed.

Redesign of the clamps should include a feature that positively locks the
clamp, IMO.
Maybe sometimes it's better to let rust happen.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Karl Townsend" wrote in message
anews.com...
My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

Karl

In article s.com,
"Karl Townsend" wrote:

My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

Karl

IIRC, nitric acid will dissolve iron and not aluminum. Test first

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/
** Posted from http://www.teranews.com **

nick hull wrote:
In article s.com,
"Karl Townsend" wrote:

My son just gave me a little job... I've got six aluminum pickup topper
clamps that used steel bolts. They are all corroded together. if you just
twist hard, the bolt will take the AL thread with it.

Short of cutting the bolt off, milling and tapping to the next size; how
would you repair this?

Karl

IIRC, nitric acid will dissolve iron and not aluminum. Test first

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/
** Posted from http://www.teranews.com **


Option 1 Heat the bolts up red hot keep the heat foof the ally as much
as possible ,the heat will travel up the bolt ,let them cool off .
Try them then .

option 2
Soak the job in diesel for a few days ,then try the bolts.


--
Kevin (Bluey)
"I'm not young enough to know everything."