Welding sintered alloys?

    --A pal of mine designs jewelry that's then manufactured using a 3-D printer and metal powders that are sintered for strength. Here's a link to
her page to give you the idea: http://www.bathsheba.com /     --I shared a show-and-tell table with her at a recent conference and she mentioned that some of her pieces were large and complex enough to require individual segments to be welded together. She sent me some scrap pieces of the stuff so I could take a whack at welding 'em together myself but B4 I do I thot you lot might have an idea of the best way to proceed. I believe the pieces I've got are made of steel; maybe 1/8" thick sections..
--
"Steamboat Ed" Haas : Time flies like an arrow
Hacking the Trailing Edge! : Fruit flies like a banana
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steamer wrote:

Are these the items that are made of a sintered stainless steel powder and then consolidated by dunking in molten bronze to fill the voids. I so I would have thought TIG bronze welding, brazing or silver soldering would be appropriate. For a colour match maybe trying to use the composite material itself might be worth a try for a TIG filler, can they generate you some rods or any offcuts that would be suitable.
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    --The samples I've got are made from stainless powder; no bronze has been added so I'm thinking TIG and nickel rod but I'm not sure if the stuff will hold up. Gotta take a whack at it I guess. Rods of the material: hmmm interesting idea; will explore further.
--
"Steamboat Ed" Haas : Time flies like an arrow
Hacking the Trailing Edge! : Fruit flies like a banana
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steamer wrote:

From the look of the items on the site I thought they had a bronze appearance and so you may have been given the initial SS powder form rather than the bronze infused SS form. From my reading the SS initial form is weak and I would expect difficult to weld or braze due to the porous nature, brazing with a flux maybe leading to inclusions of the flux and later problems. I would have thought if they were later infused with bronze then that would be a better candidate for joining with welding processes due it being a more homologous material and better heat distribution and it being a solid rather than porous material. The last item being said, maybe if all you have to do is tack some SS sintered forms together than maybe a small tack would be OK and if later bronze infused that would give strong item overall. Can they give you a few items to play with as it sounds like it might be fun to play with a few and see what can be done with it.
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On Dec 9, 3:50 pm, David Billington

Exactly, just doesn't feel to me like it'll work.

It's true that if you _could_ tack the uninfiltrated steel print, you could tack first and infiltrate after. I have not heard of this being done, e.g. to produce objects larger than the printer's build bed, and I can't think of a reason it would be better than to just welding the final infiltrated parts. But there might be a reason anyway -- it's good lateral thinking. ;-)
-Bathsheba http://bathsheba.com
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Actually Ed those samples are bronze-infiltrated. They don't really ship the uninfiltrated stainless material because it's wimpy stuff. Has about 60% porosity. I can't quite dent it with a fingernail, but someone with tougher nails might be able to, with a hacksaw it cuts like balsa.
My best guess, not having tried, would be TIG, but it is true you won't get a color match unless you fill with a rod of the same stuff. Oh well it doesn't look that great anyway.
I heard a rumor there could be an all-bronze material this year. Shh.
-Bathsheba http://bathsheba.com
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