I want to buy a few square feet of 0.005 inch thick sheet to make
some parts that are about three inches by three inches. The parts
are flat leaves that slide across each other to form a shutter. I
want some kind of alloy that will resist warping if the parts are
heated to about 800F for a short time.

Can anyone suggest some place to buy this?

Thanks

"Tim Williams" wrote in
:

"Dev Null" wrote in message
...
I want to buy a few square feet of 0.005 inch thick sheet to
make some parts that are about three inches by three inches.
The parts are flat leaves that slide across each other to form
a shutter. I want some kind of alloy that will resist warping
if the parts are heated to about 800F for a short time.

That's not terribly hot. Would stainless foil (well, not quite
foil, but not really sheet) do it?

Tim


That's what is used now and it's warping. I don't know the exact
temperature but it's hot enough to leave the current parts black
and blue and warped, let's say 1400F then? That's at least a red
heat. There's got to be something better. I've tried a bunch of
companies but they either would not recommend an alloy or didn't
have anything as thin as 0.005 inch. I'll take something a little
thicker if I can find it. If I have to make a new part I want it
to last forever. I'm willing to pay a premium for this sheet.

Dev Null wrote:

"Tim Williams" wrote in
:



"Dev Null" wrote in message
. ..


I want to buy a few square feet of 0.005 inch thick sheet to
make some parts that are about three inches by three inches.
The parts are flat leaves that slide across each other to form
a shutter. I want some kind of alloy that will resist warping
if the parts are heated to about 800F for a short time.


That's not terribly hot. Would stainless foil (well, not quite
foil, but not really sheet) do it?

Tim




That's what is used now and it's warping. I don't know the exact
temperature but it's hot enough to leave the current parts black
and blue and warped, let's say 1400F then? That's at least a red
heat. There's got to be something better. I've tried a bunch of
companies but they either would not recommend an alloy or didn't
have anything as thin as 0.005 inch. I'll take something a little
thicker if I can find it. If I have to make a new part I want it
to last forever. I'm willing to pay a premium for this sheet.


Sheet will just warp. The only way to stop it is to control the
geometry so that warpage doesn't cause a problem. Not knowing the shape
or use of the part I can only use the example of a laser cut slot in the
sheet to give some warpage control.

There are lots of materials that will take the heat...T321 stainless is
one example. 80-20 stainless is another but may be harder to find in
sheet form. Maybe you could leak some more info about the application?

Koz

Koz wrote in
:



Dev Null wrote:

"Tim Williams" wrote in
:



"Dev Null" wrote in message
. ..


I want to buy a few square feet of 0.005 inch thick sheet to
make some parts that are about three inches by three inches.
The parts are flat leaves that slide across each other to
form a shutter. I want some kind of alloy that will resist
warping if the parts are heated to about 800F for a short
time.


That's not terribly hot. Would stainless foil (well, not
quite foil, but not really sheet) do it?

Tim




That's what is used now and it's warping. I don't know the
exact temperature but it's hot enough to leave the current
parts black and blue and warped, let's say 1400F then? That's
at least a red heat. There's got to be something better. I've
tried a bunch of companies but they either would not recommend
an alloy or didn't have anything as thin as 0.005 inch. I'll
take something a little thicker if I can find it. If I have to
make a new part I want it to last forever. I'm willing to pay
a premium for this sheet.


Sheet will just warp. The only way to stop it is to control the
geometry so that warpage doesn't cause a problem. Not knowing
the shape or use of the part I can only use the example of a
laser cut slot in the sheet to give some warpage control.

There are lots of materials that will take the heat...T321
stainless is one example. 80-20 stainless is another but may be
harder to find in sheet form. Maybe you could leak some more
info about the application?

Koz


The parts are leaves in a leaf shutter for a 500W high pressure
mercury lamp optical system. The leaves sort of look like a sickle
with a short, really fat blade.

I don't care about warping when the leaf is hot. I don't want the
leaf to remain warped when it cools. The normal operating temp is
probably 200F but if there is a focus problem the leaf gets hot.
If even one leaf gets warped the shutter will jam. Which is bad.

I'm going to buy some shim stock from McMaster for now. Maybe I'll
find something evetually.

Thanks

The thinnest high-temp, small-quantity sheet stock I know of is at
McMaster Carr - 0.018 thick Hastelloy X. You could buy some stainless
steel shim stock at the thickness you want, but I don't know if it would
resist warping and/or oxidizing at that temp.

Dev Null wrote:

I want to buy a few square feet of 0.005 inch thick sheet to make
some parts that are about three inches by three inches. The parts
are flat leaves that slide across each other to form a shutter. I
want some kind of alloy that will resist warping if the parts are
heated to about 800F for a short time.

Can anyone suggest some place to buy this?

Thanks

Dev Null writes:

Can anyone suggest some place to buy this?

http://www.truetex.com/metals.htm

Dev Null wrote:

The parts are leaves in a leaf shutter for a 500W high pressure
mercury lamp optical system. The leaves sort of look like a sickle
with a short, really fat blade.

I don't care about warping when the leaf is hot. I don't want the
leaf to remain warped when it cools. The normal operating temp is
probably 200F but if there is a focus problem the leaf gets hot.
If even one leaf gets warped the shutter will jam. Which is bad.

I'm going to buy some shim stock from McMaster for now. Maybe I'll
find something evetually.
I built one of these out of BRASS shim stock, sliding on a brass
heat sink. It was in a 200 W system, and the total output of the lamp
was focussed on a 2 mm spot on the brass. I never had any problem with
warping, although there was a black spot burned into the shutter.

My shutter just had one "leaf" that blocked or opened a 2 mm hole in the
heat sink. It may have been that the light was so intense that most of
it bounced off the brass when the shutter was closed. if your shutter
is black, maybe putting a reflector on the source side of the leaves
would help keep it cool.

I suppose you could go for Titanium, they use that in jet engine exhaust
pipes, so it can definitely take the heat.

Jon

In article ,
says...



The parts are leaves in a leaf shutter for a 500W high pressure
mercury lamp optical system. The leaves sort of look like a sickle
with a short, really fat blade.

I don't care about warping when the leaf is hot. I don't want the
leaf to remain warped when it cools. The normal operating temp is
probably 200F but if there is a focus problem the leaf gets hot.
If even one leaf gets warped the shutter will jam. Which is bad.


It seems to me you the ideal material would retain its
strength at elevated temperature and have a low coefficient
of thermal expansion. Some stainless steels might be OK in
the strength criteria, but have relatively high
coefficients of expansion. Molybdenum would be a candidate,
though it will oxidize in the atmosphere at red heat. Moly
foil should be easy to get. Contact me offline if this
looks promising and you have trouble finding it.

Perhaps something like Kovar or Invar? This outfit looks to
have foil in some of the high temp alloys. It's not very
very convenient making direct comparisons on the site, but
it might tbe worth contacting them.

http://www.hightempmetals.com/technicaldata.php

Ned Simmons

Dev Null wrote:
I want to buy a few square feet of 0.005 inch thick sheet to make
some parts that are about three inches by three inches. The parts
are flat leaves that slide across each other to form a shutter. I
want some kind of alloy that will resist warping if the parts are
heated to about 800F for a short time.

Can anyone suggest some place to buy this?

Thanks

Take a look at Inconel 625. There is an outfit in Southern CA called
Thin metals that may be able to supply this material in foil. I don't
have the number handy right now. Another source might be Alltemp
alloys. Also in SOCAL. I would also suggest photo etching the leaves of
the shutter.

Good luck

Tom Lipton

Jon Elson wrote:

Dev Null wrote:


The parts are leaves in a leaf shutter for a 500W high pressure
mercury lamp optical system. The leaves sort of look like a sickle
with a short, really fat blade.

I don't care about warping when the leaf is hot. I don't want the
leaf to remain warped when it cools. The normal operating temp is
probably 200F but if there is a focus problem the leaf gets hot. If
even one leaf gets warped the shutter will jam. Which is bad.

I'm going to buy some shim stock from McMaster for now. Maybe I'll
find something evetually.

I built one of these out of BRASS shim stock, sliding on a brass
heat sink. It was in a 200 W system, and the total output of the lamp
was focussed on a 2 mm spot on the brass. I never had any problem with
warping, although there was a black spot burned into the shutter.

My shutter just had one "leaf" that blocked or opened a 2 mm hole in the
heat sink. It may have been that the light was so intense that most of
it bounced off the brass when the shutter was closed. if your shutter
is black, maybe putting a reflector on the source side of the leaves
would help keep it cool.

I suppose you could go for Titanium, they use that in jet engine exhaust
pipes, so it can definitely take the heat.

Jon

Oh, yeah, one more detail! I used a dichroic splitter to dump the heat
component
into a DIFFERENT heat sink, so the shutter was only hit with the visible
and UV
component of the lamp's output. The dichroic mirror was put at a 45
degree angle,
to bounce the short waves into the shutter. The long waves went
straight through
to the IR dump heat sink, and it got plenty hot!

Jon

In article ,
Dev Null wrote:


The parts are leaves in a leaf shutter for a 500W high pressure
mercury lamp optical system. The leaves sort of look like a sickle
with a short, really fat blade.

I don't care about warping when the leaf is hot. I don't want the
leaf to remain warped when it cools. The normal operating temp is
probably 200F but if there is a focus problem the leaf gets hot.
If even one leaf gets warped the shutter will jam. Which is bad.

Why don't you re-design the shutter so it only has 2 overlapping pieces,
sheets with a "V" notch to give you an adjustable square opening. The
pieces can be a lot thicker and there will be less jamming and more
ability to take the heat.

--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/

Nick Hull wrote in
:

In article ,
Dev Null wrote:


The parts are leaves in a leaf shutter for a 500W high
pressure mercury lamp optical system. The leaves sort of look
like a sickle with a short, really fat blade.

I don't care about warping when the leaf is hot. I don't want
the leaf to remain warped when it cools. The normal operating
temp is probably 200F but if there is a focus problem the leaf
gets hot. If even one leaf gets warped the shutter will jam.
Which is bad.

Why don't you re-design the shutter so it only has 2 overlapping
pieces, sheets with a "V" notch to give you an adjustable square
opening. The pieces can be a lot thicker and there will be less
jamming and more ability to take the heat.


I'm trying to repair existing equipment so I have to go with what's
there. Vibration would be bad so I don't want to make heavy parts.
Also the exposure time (several seconds) is important so I want the
shutter to be fast.

We have the dichroic mirror too but I guess that only goes so far.

I can get the parts EDM'ed. I'm hacking together a dxf file for
this.

I found some Inconel 600A shim stock at McMaster Carr so I'm going
with that for now.

Thanks for everyone's suggestions.