Brass Welding Question

By Blaster (***)

Date 11-10-2010 02:27

I have a little favor job that walked into the shop. A guy wants me to do some build up on a brass component off a muzzle loader. It is an end cap that will go at the muzzle end of the wood stock. It is made of a U-shaped brass casting, about 1/8" thick. No idea what the exact alloy is. It is a one of a kind item that can't be bought new so I really don't want to ruin it.

Anyhow I was wondering if it may be feasible to TIG weld it. I have only tried TIG welding a brass alloy once before. I tried it on EN and it seemed the brass (alloyed with Zinc maybe?) would fume and outgas almost instantly upon getting a puddle.

So is TIG a potentially feasible option for such a job?

If it can be welded, I am pretty confident I can get it done with an OF torch, but I think I could do a much nicer job with TIG if that process is possible.

If this sound feasible with TIG, any tips on set up or procedure that may be likely to be successful?

Thanks

By DaveBoyer (*****)

Date 11-10-2010 02:48

I know guys who tig braze, but they are using silicon bronze filler on silicon bronze.

Regardless of what You use as a heat source, I tink You should check the color match of the filler on a non visable surface first.

By Joseph P. Kane (****)

Date 11-10-2010 16:04

Blaster

I do not recommend GTA welding on brass. The Zinc outgassing that you experienced is typical with repairs performed with GTA.

If the part is simply broken off, I recommend a silver braze with Eutectic 1020 XFC. It has a good liquidus - solidus temperature differential, and with care can be used to free flow or do small build up It also offers a good (but not perfect) color match when used in the liquid free flow application. It is also cadmium free and has high UTS.

It is also a very expensive flux coated brazing rod, but us a very useful low temperature silver brazing rod for stainless food service and ornamental repairs.

Joe Kane

By rlitman (***)

Date 11-10-2010 19:32

Although the question isn't clear, I'm assuming the OP was looking to add some brass to a casting, and not repair a broken part.
If that is the case, there is no good answer, as a silver braze will not give a good color match at all.

I suppose it could be build up with a braze, and sent out for plating, but this goes way past the "little favor" status of the job.

Anyway, GTAW probably isn't the best choice, but at least under the argon shield, IF you can avoid boiling off the zinc with the high temperature of TIG, you may end up with less polishing work to do. I tend to stick to O/A for brazing though.

By G.S.Crisi (****)

Date 11-10-2010 17:25

Why don't you consider the good old oxy-acetylene welding that was used when I was young with excellent results?
Giovanni S. Crisi
Sao Paulo - Brazil