On Wed, 20 Jun 2018 14:05:54 -0500, Terry Coombs
wrote:

On 6/20/2018 12:16 PM, Gunner Asch wrote:
On Wed, 20 Jun 2018 06:36:20 -0500, Terry Coombs
wrote:

Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of tungsten
rod welded/brazed to a stainless steel handle . The join is not subject
to the full heat of molten glass . Am I right in assuming that a TIG
torch set on DCEN will melt and fuse these two metals without filler ?
What filler is recommended ? I have on hand 308 309/309l , and some 312
in various sizes . I also have some ER70S2 on hand and some Invar42
nickel/iron filler . She indicates that these must be pretty straight ,
no wobbles when they are spun or rolled across a flat surface . I'm
thinking a long vee block with a cutout in the middle , maybe a spring
on one end to keep things pushed together . We're getting into uncharted
territory here for me , I'm open to suggestions - that pertain to the
task at hand , please .

Tungsten cannot be "welded". It can be brazed..and it can be "silver
soldered"..but it really cannot be "welded"..


https://www.brazing.com/products/Bra...ingFluxes.aspx

http://www.carbideprocessors.com/pag...n-carbide.html

Im sure others here have done this far more than I have...Im looking
forwards to their responses.
Its an interesting problem!



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* This project uses metallic tungsten , not tungsten carbide . If my
TIG welder can get an arc hot enough to ball the tungsten , I'm pretty
sure it can melt it on the positive side of a DC arc .
You certainly can melt the tungsten with a TIG welder but welding it
to the SS is the problem. If you do go with silver solder the tungsten
should be covered with flux to avoid excessive oxidation.
Eric