"Terry Keeley" tkee(no wrote in message
...
Thanks again Ed, so high tensile strength is what I'm after.

Actually weight is a huge factor, these are for record attempt boats and
any weight on the right sponson has to be minimized to help counter
prop-walk. I'm running in a class that has a 120+ mph record and my buddy
I mentioned just broke the record in his class running 103+, here's pix if
you're interested:

http://gallery.intlwaters.com/thumbnails.php?album=1002

Here's the fin I'm talking about on my hull:

http://gallery.intlwaters.com/albums...anImage011.jpg

Oh, those are cool, Terry, and they look like a lot of fun. We were
discussing here recently that my uncle raced model hydros like that in the
1930s, in a 35cc IC class and in a steam class (he used gasoline-fired flash
steam). I sure wish I had the photos of those.


Wonder if one of the magnesium alloys might be better?

It looks to me like you have four engineering factors he weight,
hydrodynamic drag, stiffness, and strength. Magnesium has roughly the same
ratio of strength/weight and stiffness/weight of most metals (titanium is
somewhat out of line, having high strength/weight but low stiffness for its
strength). So magnesium would result in a thicker, if somewhat ligher, fin.

I couldn't begin to evaluate the engineering options, but as a materials
freak, the first thing I would look at is unidirectional boron-fiber
aluminum composite. The second thing I'd look into would be a boron-fiber
epoxy composite. I'm not making life easy for you with that one. d8-)

--
Ed Huntress

Ed Huntress wrote:

"Terry Keeley" tkee(no wrote in message
...

Thanks again Ed, so high tensile strength is what I'm after.

Actually weight is a huge factor, these are for record attempt boats and
any weight on the right sponson has to be minimized to help counter
prop-walk. I'm running in a class that has a 120+ mph record and my buddy
I mentioned just broke the record in his class running 103+, here's pix if
you're interested:

http://gallery.intlwaters.com/thumbnails.php?album=1002

Here's the fin I'm talking about on my hull:

http://gallery.intlwaters.com/albums...anImage011.jpg


Oh, those are cool, Terry, and they look like a lot of fun. We were
discussing here recently that my uncle raced model hydros like that in the
1930s, in a 35cc IC class and in a steam class (he used gasoline-fired flash
steam). I sure wish I had the photos of those.


Wonder if one of the magnesium alloys might be better?


It looks to me like you have four engineering factors he weight,
hydrodynamic drag, stiffness, and strength. Magnesium has roughly the same
ratio of strength/weight and stiffness/weight of most metals (titanium is
somewhat out of line, having high strength/weight but low stiffness for its
strength). So magnesium would result in a thicker, if somewhat ligher, fin.

I couldn't begin to evaluate the engineering options, but as a materials
freak, the first thing I would look at is unidirectional boron-fiber
aluminum composite. The second thing I'd look into would be a boron-fiber
epoxy composite. I'm not making life easy for you with that one. d8-)

--
Ed Huntress



Is this really a materials issue?

Or Temper?



--
(remove the X to email)

Now just why the HELL do I have to press 1 for English?
John Wayne

"cavelamb himself" wrote in message
m...
Ed Huntress wrote:

"Terry Keeley" tkee(no wrote in message
...

Thanks again Ed, so high tensile strength is what I'm after.

Actually weight is a huge factor, these are for record attempt boats and
any weight on the right sponson has to be minimized to help counter
prop-walk. I'm running in a class that has a 120+ mph record and my buddy
I mentioned just broke the record in his class running 103+, here's pix
if you're interested:

http://gallery.intlwaters.com/thumbnails.php?album=1002

Here's the fin I'm talking about on my hull:

http://gallery.intlwaters.com/albums...anImage011.jpg


Oh, those are cool, Terry, and they look like a lot of fun. We were
discussing here recently that my uncle raced model hydros like that in
the 1930s, in a 35cc IC class and in a steam class (he used
gasoline-fired flash steam). I sure wish I had the photos of those.


Wonder if one of the magnesium alloys might be better?


It looks to me like you have four engineering factors he weight,
hydrodynamic drag, stiffness, and strength. Magnesium has roughly the
same ratio of strength/weight and stiffness/weight of most metals
(titanium is somewhat out of line, having high strength/weight but low
stiffness for its strength). So magnesium would result in a thicker, if
somewhat ligher, fin.

I couldn't begin to evaluate the engineering options, but as a materials
freak, the first thing I would look at is unidirectional boron-fiber
aluminum composite. The second thing I'd look into would be a boron-fiber
epoxy composite. I'm not making life easy for you with that one. d8-)

--
Ed Huntress

Is this really a materials issue?

Or Temper?

If the object is to have the highest possible stiffness and strength for a
given density, it's really a materials issue -- and metal-matrix composites
look to me like the winner. Since the volume of material is low and the
objective is very high, it may be worth the effort and hassle.

And it is a hassle. Just cutting the stuff can be a nightmare. BTW, most of
the aluminum composites available today are not boron-fiber reinforced, but
other ceramics, like aluminum oxide and boron nitride.

--
Ed Huntress

Having the fin as thin as possible is the most important, then weight and
strength. Looks like a heat-treated Ti alloy is in fact the best choice,
other than some "unobtainium", LOL!

Thanks again for all your help, my goal is to travel our 330' course in 1.8
sec!



"Ed Huntress" wrote in message
...

"cavelamb himself" wrote in message
m...
Ed Huntress wrote:

"Terry Keeley" tkee(no wrote in message
...

Thanks again Ed, so high tensile strength is what I'm after.

Actually weight is a huge factor, these are for record attempt boats and
any weight on the right sponson has to be minimized to help counter
prop-walk. I'm running in a class that has a 120+ mph record and my
buddy I mentioned just broke the record in his class running 103+,
here's pix if you're interested:

http://gallery.intlwaters.com/thumbnails.php?album=1002

Here's the fin I'm talking about on my hull:

http://gallery.intlwaters.com/albums...anImage011.jpg


Oh, those are cool, Terry, and they look like a lot of fun. We were
discussing here recently that my uncle raced model hydros like that in
the 1930s, in a 35cc IC class and in a steam class (he used
gasoline-fired flash steam). I sure wish I had the photos of those.


Wonder if one of the magnesium alloys might be better?


It looks to me like you have four engineering factors he weight,
hydrodynamic drag, stiffness, and strength. Magnesium has roughly the
same ratio of strength/weight and stiffness/weight of most metals
(titanium is somewhat out of line, having high strength/weight but low
stiffness for its strength). So magnesium would result in a thicker, if
somewhat ligher, fin.

I couldn't begin to evaluate the engineering options, but as a materials
freak, the first thing I would look at is unidirectional boron-fiber
aluminum composite. The second thing I'd look into would be a
boron-fiber epoxy composite. I'm not making life easy for you with that
one. d8-)

--
Ed Huntress

Is this really a materials issue?

Or Temper?

If the object is to have the highest possible stiffness and strength for a
given density, it's really a materials issue -- and metal-matrix
composites look to me like the winner. Since the volume of material is low
and the objective is very high, it may be worth the effort and hassle.

And it is a hassle. Just cutting the stuff can be a nightmare. BTW, most
of the aluminum composites available today are not boron-fiber reinforced,
but other ceramics, like aluminum oxide and boron nitride.

--
Ed Huntress

"Terry Keeley" tkee(no wrote in message
...
Having the fin as thin as possible is the most important, then weight and
strength. Looks like a heat-treated Ti alloy is in fact the best choice,
other than some "unobtainium", LOL!

Thanks again for all your help, my goal is to travel our 330' course in
1.8 sec!

Well, good luck. Let us know how you do with it.

--
Ed Huntress

Sure will thanks!


"Ed Huntress" wrote in message
...

"Terry Keeley" tkee(no wrote in message
...
Having the fin as thin as possible is the most important, then weight and
strength. Looks like a heat-treated Ti alloy is in fact the best choice,
other than some "unobtainium", LOL!

Thanks again for all your help, my goal is to travel our 330' course in
1.8 sec!

Well, good luck. Let us know how you do with it.

--
Ed Huntress

Guessing here, but maybe you are looking for Titanium-Nickel
alloy (TiNi)?

If I remember correctly that is what the bows are made of on
my glasses. You can bend them almost 90 deg and they will
spring back to their original shape. Here is some info from
a research project I found:

===
"Tensile Properties and Transformation Temperatures of Ti-Ni
Alloy Dental Castings Added Cu

Hisashi Doi, Equo Kobayashi, Takayuki Yoneyama and Hitoshi
Hamanaka

Department of Metallurgy, Division of Biomaterials,
Institute of Biomaterials and Bioengineering, Tokyo Medical
and Dental University
(2-3-10, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062)
Original Paper: J J Dent Mate Vol. 20 No. 1 48-53 (2001)
Keyword: Titanium-nickel alloy, Superelasticity, Mechanical
properties

The application of the Ti-Ni base alloy to dentistry is
expected to utilize its shape memory effect and
super-elasticity properties. The transformation temperature
changes when part of the nickel in a Ti-Ni alloy is replaced
with copper. In this study, the super-elastic property of
Ti-Ni alloy in which part of the nickel was replaced with
10mol% of copper was investigated, and the application of
this alloy to dental casting was also examined. The results
of this study showed that the super-elasticity of dental
casted Ti-Ni-Cu alloy with 10mol% of replacement copper was
good and that this maybe a useful method of reducing the
quantity of nickel in Ti-Ni based alloy."
===

From Mat-world:

Titanium Nickel Alloy
TiNi Alloy
Ti-Ni (50:50 wt%)
Ingots, Wires, Sputtering Target, Sheet, Plate, Disk

http://www.mat-world.com/En_elements/ti.html

Maybe this is the stuff you are looking for or could use...

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

On Wed, 7 May 2008 19:34:20 -0400, "Ed Huntress"
wrote:


"Terry Keeley" tkee(no wrote in message
...
Having the fin as thin as possible is the most important, then weight and
strength. Looks like a heat-treated Ti alloy is in fact the best choice,
other than some "unobtainium", LOL!

Thanks again for all your help, my goal is to travel our 330' course in
1.8 sec!

Well, good luck. Let us know how you do with it.

can you work harden titanium by hammering it to shape?

Thanks for the reply, but no, I need to put a slight bend in it, just need
it to be stronger than the annealed stuff I have.

Found out the "other" alloys (662, 6242, 6246) harden better than good 'ol
6-4, so I'm looking for something like this:

http://www.matweb.com/search/DataShe...D=14246&ckck=1

Tensile way up there and quite a bit harder too. Turns out that finding
heat-treated Ti isn't that easy, most of the robot places and surplus on
e-bay only have annealed.

Anyone have any idea where to fin a small amount of 0.025-0.030" hardened
sheet?

TIA



"Leon Fisk" wrote in message
...
Guessing here, but maybe you are looking for Titanium-Nickel
alloy (TiNi)?

If I remember correctly that is what the bows are made of on
my glasses. You can bend them almost 90 deg and they will
spring back to their original shape. Here is some info from
a research project I found:

===
"Tensile Properties and Transformation Temperatures of Ti-Ni
Alloy Dental Castings Added Cu

Hisashi Doi, Equo Kobayashi, Takayuki Yoneyama and Hitoshi
Hamanaka

Department of Metallurgy, Division of Biomaterials,
Institute of Biomaterials and Bioengineering, Tokyo Medical
and Dental University
(2-3-10, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062)
Original Paper: J J Dent Mate Vol. 20 No. 1 48-53 (2001)
Keyword: Titanium-nickel alloy, Superelasticity, Mechanical
properties

The application of the Ti-Ni base alloy to dentistry is
expected to utilize its shape memory effect and
super-elasticity properties. The transformation temperature
changes when part of the nickel in a Ti-Ni alloy is replaced
with copper. In this study, the super-elastic property of
Ti-Ni alloy in which part of the nickel was replaced with
10mol% of copper was investigated, and the application of
this alloy to dental casting was also examined. The results
of this study showed that the super-elasticity of dental
casted Ti-Ni-Cu alloy with 10mol% of replacement copper was
good and that this maybe a useful method of reducing the
quantity of nickel in Ti-Ni based alloy."
===

From Mat-world:

Titanium Nickel Alloy
TiNi Alloy
Ti-Ni (50:50 wt%)
Ingots, Wires, Sputtering Target, Sheet, Plate, Disk

http://www.mat-world.com/En_elements/ti.html

Maybe this is the stuff you are looking for or could use...

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

"Stealth Pilot" wrote in message
...
On Wed, 7 May 2008 19:34:20 -0400, "Ed Huntress"
wrote:


"Terry Keeley" tkee(no wrote in message
...
Having the fin as thin as possible is the most important, then weight
and
strength. Looks like a heat-treated Ti alloy is in fact the best
choice,
other than some "unobtainium", LOL!

Thanks again for all your help, my goal is to travel our 330' course in
1.8 sec!

Well, good luck. Let us know how you do with it.

can you work harden titanium by hammering it to shape?

Titanium alloys in general don't work-harden very much. Some, hardly at all.
The stronger titanium alloys are hardened by precipitation hardening, much
like aluminum and the precipitation-hardening stainless steels (17-7PH,
A-386, etc.).

--
Ed Huntress

On Fri, 9 May 2008 08:48:28 -0400, "Terry Keeley" tkee(no
wrote:

Thanks for the reply, but no, I need to put a slight bend in it, just need
it to be stronger than the annealed stuff I have.

Found out the "other" alloys (662, 6242, 6246) harden better than good 'ol
6-4, so I'm looking for something like this:

http://www.matweb.com/search/DataShe...D=14246&ckck=1

Tensile way up there and quite a bit harder too. Turns out that finding
heat-treated Ti isn't that easy, most of the robot places and surplus on
e-bay only have annealed.

Anyone have any idea where to fin a small amount of 0.025-0.030" hardened
sheet?

No idea, but I would try being honest with some of the big
suppliers and see if they might help. Just send out some
email explaining what you what to try and the application
for it and see what happens. Sometimes these places will
help the little guy out.

I found this place that seems to have something like what
you want:

http://www.harveytitanium.com/produc...2Sn4Zr2Mo.aspx

I think this place is related to the previous:

http://www.rolledalloys.com/trc/6Al2Sn4Zr2Mo.aspx

and a ThomasNet search:

http://www.thomasnet.com/products/fo...0870257-1.html

Good luck...

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

On May 9, 5:50 am, "Ed Huntress" wrote:


Titanium alloys in general don't work-harden very much. Some, hardly at all.
The stronger titanium alloys are hardened by precipitation hardening, much
like aluminum and the precipitation-hardening stainless steels (17-7PH,
A-386, etc.).

--
Ed Huntress

I thought titanium alloys did work harden and that made them difficult
to machine.
In that you needed to get the tool under the work-hardened layer.

Dan

wrote in message
...
On May 9, 5:50 am, "Ed Huntress" wrote:


Titanium alloys in general don't work-harden very much. Some, hardly at
all.
The stronger titanium alloys are hardened by precipitation hardening,
much
like aluminum and the precipitation-hardening stainless steels (17-7PH,
A-386, etc.).

--
Ed Huntress

I thought titanium alloys did work harden and that made them difficult
to machine.
In that you needed to get the tool under the work-hardened layer.

Dan

Not that I know of, Dan. Titanium has a reputation for not work-hardening
very much. It's worth checking out, in the machining context, but I'm pretty
sure that's the situation in general.

Titanium can be miserable to machine -- I remember doing some machining of
it back in the mid-'70s -- but my recollection is that it was more tough and
gummy than hard. But that's pretty far back in memory for me.

--
Ed Huntress

Thanks much, I did look at Harvey Titanium and may just make some calls...


"Leon Fisk" wrote in message
...
On Fri, 9 May 2008 08:48:28 -0400, "Terry Keeley" tkee(no
wrote:

Thanks for the reply, but no, I need to put a slight bend in it, just need
it to be stronger than the annealed stuff I have.

Found out the "other" alloys (662, 6242, 6246) harden better than good 'ol
6-4, so I'm looking for something like this:

http://www.matweb.com/search/DataShe...D=14246&ckck=1

Tensile way up there and quite a bit harder too. Turns out that finding
heat-treated Ti isn't that easy, most of the robot places and surplus on
e-bay only have annealed.

Anyone have any idea where to fin a small amount of 0.025-0.030" hardened
sheet?

No idea, but I would try being honest with some of the big
suppliers and see if they might help. Just send out some
email explaining what you what to try and the application
for it and see what happens. Sometimes these places will
help the little guy out.

I found this place that seems to have something like what
you want:

http://www.harveytitanium.com/produc...2Sn4Zr2Mo.aspx

I think this place is related to the previous:

http://www.rolledalloys.com/trc/6Al2Sn4Zr2Mo.aspx

and a ThomasNet search:

http://www.thomasnet.com/products/fo...0870257-1.html

Good luck...

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

On May 9, 8:04 pm, "Ed Huntress" wrote:

Not that I know of, Dan. Titanium has a reputation for not work-hardening
very much. It's worth checking out, in the machining context, but I'm pretty
sure that's the situation in general.

Titanium can be miserable to machine -- I remember doing some machining of
it back in the mid-'70s -- but my recollection is that it was more tough and
gummy than hard. But that's pretty far back in memory for me.

--
Ed Huntress

Hmmm. I did a little looking on the internet and found sites that
said Titanium work hardens about like 1020 steel, that is not a lot.
But they followed this with warnings not to do anything that would
work harden it. Possibly more because it will gall and also because
it does not conduct heat well. So it sounds as if you can't harden
titanium much by work hardening, you need to machine it as if it does
work harden.

Dan

wrote in message
...
On May 9, 8:04 pm, "Ed Huntress" wrote:

Not that I know of, Dan. Titanium has a reputation for not work-hardening
very much. It's worth checking out, in the machining context, but I'm
pretty
sure that's the situation in general.

Titanium can be miserable to machine -- I remember doing some machining
of
it back in the mid-'70s -- but my recollection is that it was more tough
and
gummy than hard. But that's pretty far back in memory for me.

--
Ed Huntress

Hmmm. I did a little looking on the internet and found sites that
said Titanium work hardens about like 1020 steel, that is not a lot.
But they followed this with warnings not to do anything that would
work harden it. Possibly more because it will gall and also because
it does not conduct heat well. So it sounds as if you can't harden
titanium much by work hardening, you need to machine it as if it does
work harden.

Dan

In the sense that it's not easy to machine, I suppose that's true. But
again, I remember it being tough and requiring a lot of power to cut, not
that it's hard. The maximum hardness you can get with titanium alloys, IIRC,
is in the range of Rc 40.

I'm sure there's good info on machining it around the Web. I just haven't
looked. The public-transportation guys have been keeping me busy. d8-)

--
Ed Huntress

On Sat, 10 May 2008 08:17:16 -0700 (PDT), "
wrote:

On May 9, 8:04 pm, "Ed Huntress" wrote:

Not that I know of, Dan. Titanium has a reputation for not work-hardening
very much. It's worth checking out, in the machining context, but I'm pretty
sure that's the situation in general.

Titanium can be miserable to machine -- I remember doing some machining of
it back in the mid-'70s -- but my recollection is that it was more tough and
gummy than hard. But that's pretty far back in memory for me.

--
Ed Huntress

Hmmm. I did a little looking on the internet and found sites that
said Titanium work hardens about like 1020 steel, that is not a lot.
But they followed this with warnings not to do anything that would
work harden it. Possibly more because it will gall and also because
it does not conduct heat well. So it sounds as if you can't harden
titanium much by work hardening, you need to machine it as if it does
work harden.

Dan

At one point I did some work on the SR-71's which had titanium skin. I
have no idea what alloy it was but it seemed similar to stainless
except that it work hardened even worse. It seemed like if the drill
slipped for one revolution the stuff became uncutable. We used a lot
of carbide drill bits in the short time we supported them.


Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

On Sun, 11 May 2008 14:20:16 +0700, Bruce in Bangkok
wrote:

On Sat, 10 May 2008 08:17:16 -0700 (PDT), "
wrote:

On May 9, 8:04 pm, "Ed Huntress" wrote:

Not that I know of, Dan. Titanium has a reputation for not work-hardening
very much. It's worth checking out, in the machining context, but I'm pretty
sure that's the situation in general.

Titanium can be miserable to machine -- I remember doing some machining of
it back in the mid-'70s -- but my recollection is that it was more tough and
gummy than hard. But that's pretty far back in memory for me.

--
Ed Huntress

Hmmm. I did a little looking on the internet and found sites that
said Titanium work hardens about like 1020 steel, that is not a lot.
But they followed this with warnings not to do anything that would
work harden it. Possibly more because it will gall and also because
it does not conduct heat well. So it sounds as if you can't harden
titanium much by work hardening, you need to machine it as if it does
work harden.

Dan

At one point I did some work on the SR-71's which had titanium skin. I
have no idea what alloy it was but it seemed similar to stainless
except that it work hardened even worse. It seemed like if the drill
slipped for one revolution the stuff became uncutable. We used a lot
of carbide drill bits in the short time we supported them.


Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

that is my experience with working a piece. filing it to shape is
just as difficult as drilling btw.

Stealth Pilot

I missed the Staff meeting, but the Memos showed that Bruce in Bangkok
wrote on Sun, 11 May 2008 14:20:16
+0700 in rec.crafts.metalworking :
On Sat, 10 May 2008 08:17:16 -0700 (PDT), "
wrote:

On May 9, 8:04 pm, "Ed Huntress" wrote:

Not that I know of, Dan. Titanium has a reputation for not work-hardening
very much. It's worth checking out, in the machining context, but I'm pretty
sure that's the situation in general.

Titanium can be miserable to machine -- I remember doing some machining of
it back in the mid-'70s -- but my recollection is that it was more tough and
gummy than hard. But that's pretty far back in memory for me.

--
Ed Huntress

Hmmm. I did a little looking on the internet and found sites that
said Titanium work hardens about like 1020 steel, that is not a lot.
But they followed this with warnings not to do anything that would
work harden it. Possibly more because it will gall and also because
it does not conduct heat well. So it sounds as if you can't harden
titanium much by work hardening, you need to machine it as if it does
work harden.

Dan

At one point I did some work on the SR-71's which had titanium skin. I
have no idea what alloy it was but it seemed similar to stainless
except that it work hardened even worse. It seemed like if the drill
slipped for one revolution the stuff became uncutable. We used a lot
of carbide drill bits in the short time we supported them.

We make skid plates fro the tails of Lear Jets. The reason, so
I'm told, is just that - if they scrap it on the tarmac, it doesn't
_all_ wear off in one fell swoosh.
But they sure do take forever and three shifts to machine.
--
pyotr filipivich
"I had just been through hell and must have looked like death warmed
over walking into the saloon, because when I asked the bartender
whether they served zombies he said, ‘Sure, what'll you have?'"
from I Hear America Swinging by Peter DeVries