Hi,

I'm wondering what the best way to do this is (I'm not a metal
worker). I have a spherical aluminum mesh, 3" in diameter, sliced in
half. I want to join the circular edge of one of these halves to a
piece of aluminum foil. In addition, the resulting merged unit must
be thermally stable, as it will be exposed to (relatively low) heat
when used (ie., no glues or adhesives). The joining itself will not
be under extreme stress or weight in use, so one or 2 joining spots
are enough, enough to keep it tacked in place.

Is there a welding (or other) process that can accomplish this?

Thank you

"Dimi Shahbaz" wrote in message
...
Hi,

I'm wondering what the best way to do this is (I'm not a metal
worker). I have a spherical aluminum mesh, 3" in diameter, sliced in
half. I want to join the circular edge of one of these halves to a
piece of aluminum foil. In addition, the resulting merged unit must
be thermally stable, as it will be exposed to (relatively low) heat
when used (ie., no glues or adhesives). The joining itself will not
be under extreme stress or weight in use, so one or 2 joining spots
are enough, enough to keep it tacked in place.

Is there a welding (or other) process that can accomplish this?

Thank you


3M makes an epoxy that is good to 500F

There a number of ways.
If your materials have sufficient thickness they can be TIG welded.
Thin materials can be furnace brazed.
For low temperature applications there are solders for Aluminum.

How about giving me some numbers, dimensions, and the quantity, is
this a thoudsand or a one off?
Dave


Hi,

I'm wondering what the best way to do this is (I'm not a metal
worker). I have a spherical aluminum mesh, 3" in diameter, sliced in
half. I want to join the circular edge of one of these halves to a
piece of aluminum foil. In addition, the resulting merged unit must
be thermally stable, as it will be exposed to (relatively low) heat
when used (ie., no glues or adhesives). The joining itself will not
be under extreme stress or weight in use, so one or 2 joining spots
are enough, enough to keep it tacked in place.

Is there a welding (or other) process that can accomplish this?

Thank you

As far as thickness, I think that's a problem. I want to use regular
commercial aluminum foil, so 0.2 mm thickness. The diameter of the
mesh will be 3", the foil will extend past that a few inches. If it
can be made in the thousands, that would be ideal, and preferably at a
low cost. Non-corrosive metals other than aluminum would be fine as
well, if the process is easier.

Thanks again



On Feb 4, 10:05 pm, Mechanical Magic
wrote:
There a number of ways.
If your materials have sufficient thickness they can be TIG welded.
Thin materials can be furnace brazed.
For low temperature applications there are solders for Aluminum.

How about giving me some numbers, dimensions, and the quantity, is
this a thoudsand or a one off?
Dave

On Mon, 4 Feb 2008 23:38:34 -0800 (PST), Dimi Shahbaz
wrote:

As far as thickness, I think that's a problem. I want to use regular
commercial aluminum foil, so 0.2 mm thickness. The diameter of the
mesh will be 3", the foil will extend past that a few inches. If it
can be made in the thousands, that would be ideal, and preferably at a
low cost. Non-corrosive metals other than aluminum would be fine as
well, if the process is easier.


RTV silicone should work. There are easily available formulations good
up to 500F. The common hardware store stuff is usable to 350F. More
exotic flavors go higher.

Some sort of air powered dispenser and perhaps some fixturing would be
helpful if you're making thousands.

--
Ned Simmons

OK, if I have this right, you have a hemisphere of thin aluminum mesh.
You also have a cylinder of foil (.2mm) that you want to join to the
cut edge of the hemi.
You are going to heat this above 500 f, ruling out epoxies.

?? How hot are you going to go?

You need to make a few thousand.
Strength is not an issue.

The following are some thoughts:
Spot welding
Rivets
Aluminum Solder (depends on question above)
Electron Beam welding

If this assembly looks like a cup in a tube, then crimping.

My worry is strength, and the direction of forces, any further info
might help.
Dave




On Feb 4, 11:38 pm, Dimi Shahbaz wrote:
As far as thickness, I think that's a problem. I want to use regular
commercial aluminum foil, so 0.2 mm thickness. The diameter of the
mesh will be 3", the foil will extend past that a few inches. If it
can be made in the thousands, that would be ideal, and preferably at a
low cost. Non-corrosive metals other than aluminum would be fine as
well, if the process is easier.

Thanks again

On Feb 4, 10:05 pm, Mechanical Magic
wrote:

There a number of ways.
If your materials have sufficient thickness they can be TIG welded.
Thin materials can be furnace brazed.
For low temperature applications there are solders for Aluminum.

How about giving me some numbers, dimensions, and the quantity, is
this a thoudsand or a one off?
Dave

"Dimi Shahbaz" wrote in message
...
As far as thickness, I think that's a problem. I want to use regular
commercial aluminum foil, so 0.2 mm thickness. The diameter of the
mesh will be 3", the foil will extend past that a few inches. If it
can be made in the thousands, that would be ideal, and preferably at a
low cost. Non-corrosive metals other than aluminum would be fine as
well, if the process is easier.

Thanks again

If we're voting here, I generally agree with Ned. Any kind of metal joining
(soldering, brazing, etc.) is extremely difficult with aluminum foil,
although I have soldered it with success, after many attempts. The point
contact, however, would make that a problem.

Epoxies and silicone adhesives can take a fair amount of heat, as others
have reported. Getting a strong bond to aluminum foil is, again, a problem.
Unless you use special techniques to prepare the aluminum, you will be
bonding to the surface layer of aluminum oxide, not the aluminum itself.

That's generally a weak bond. But you can't apply much load to aluminum foil
anyway, so just gluing it may work. Although I favor epoxies for most
bonding, and silicone is not a great adhesive, the silicone will be more
compliant and it may do a better job in this case.

If it were me I'd try the silicone adhesive as a test and see if it's
sufficient. If it is, it's probably the easiest and cheapest to apply.

--
Ed Huntress

On Feb 5, 7:38 am, Dimi Shahbaz wrote:
As far as thickness, I think that's a problem. I want to use regular
commercial aluminum foil, so 0.2 mm thickness. The diameter of the
mesh will be 3", the foil will extend past that a few inches. If it
can be made in the thousands, that would be ideal, and preferably at a
low cost. Non-corrosive metals other than aluminum would be fine as
well, if the process is easier.

Thanks again

I would seriously consider using slightly thicker aluminum foil. Then
form and pierce the foil to form the mesh part. If you are making
thousands it would be much quicker than using any sort of adhesive ,
welding, or soldering.


Dan

On Feb 4, 9:12*pm, Dimi Shahbaz wrote:


I'm wondering what the best way to do this is (I'm not a metal
worker). *I have a spherical aluminum mesh, 3" in diameter, sliced in
half. *I want to join the circular edge of one of these halves to a
piece of aluminum foil.

Shaped meshwork is common in vacuum tubes and
electron microscopes... the usual procedure is to form the
mesh, then electroplate it to fix all the wire-crossing points.
Aluminum isn't the preferred material, of course, but some
alloys might accept plating adequately.