Copper Welding....

Date 01-11-2011 15:32

Hey guys,
I had an interesting job come in on the weekend with a customer needing some copper tubing(1/2"OD x .062wall) "welded". They were simple cross joints of the outside of the tubes he has bent into artistic configurations. He makes decorative artwork with the taxidermy mountings he creates. Anyway, after discussing the parameters of "welding" copper, I managed to convince him to simply sil-sol this particular project as he needed it asap. The job came out quite nicely as he was satisfied, although asked me if I could research copper welding via autogenous welding or using a Cu filler. I have ER CuSi bronze MIG wire & ER Cu MIG wire which is deoxidized wire. He indicated he would really like to maintain the copper color & the copper filler would be more aesthetic for his needs as many of his works are displayed in craft/art shows. I did explain the cost variances & would do some homework.

Ok, my query is if any of you familiar with copper fusion could recommend a procedure to use the ER Cu w/MIG & I am considering either Ar or Ar/mix. Since these are thin-walled tubings, which application would you favor & gas/mix? He also asked if a filler such as 8-10ga copper wire could be used & I kinda felt it may not be conducive to "welding" as it is not deoxidized. I have 250A of MIG power available & spoolguns. Ok.... I'm listening. Thanks......

Denny

By OBEWAN

Date 01-11-2011 16:15

Here is a good copper welding guide with some set-up tables:

http://www.brazing.com/techguide/procedures/copper_welding.asp

By Lawrence (*****)

Date 01-11-2011 22:45

Obewan That article was amazing... I pasted the whole thing into a word doc.

Yorkiepap,

I've welded a bunch of copper with GTAW.. All of it for various forms of argon backups. Ive used everything from BAg-7 braze wire to 347 stainless to Hastelloy-W to thick copper wire scavanged from the scrap bin with the insulation stripped off... Since these were not code welds I guess I would say they all worked equally well.. Of course the color match was better with the stripped wire.. Outside corner joints will weld autogenously with a tight fit and maybe a dab of filler to get it started, but I like filler better.

Takes alot of heat, but straight argon is fine... A helium mix might help for thicker sections, but thats an unnecessary cost unless production speed is an issue.

I wouldn't be surprised if one of the GMAWP proggies worked ok with your spool of filler and made for a much smaller filler size and less burn thru than regular spray transfer.

By yorkiepap (***)

Date 01-12-2011 00:34

Hey guys,
Thanks for the input.

OBEWAN: Yes, that link was superb as I also did as Lawrence & printed a copy for my notebook.

Lawrence: I'm gonna try some #8 copper wire as I have a small roll of it & try it with TIG. I have to call the fellow to find out the exact grade of copper he got as he indicated it was not copper plumbing tube because he needed exactly 1/2" OD. I had a senior moment & forgot to take a pic.....duuuhhhhh, although he did say he would send me a finished pic.

I'll post some pics when I achieve success with parameters used. Thanks again....

Denny

By DaveBoyer (*****)

Date 01-12-2011 03:18

My guess is He used copper TUBE as opposed to copper PIPE. This would be the tube used for HVAC refrigerant lines, it is accurate size on the OD.

I have seen the Henrob/Dilon torch guy "braze" steel with copper electrical wire, I understand that is a whole other banana, but My guess is the copper tube & copper wire are as similar as You will find.

By 357max

Date 01-11-2011 23:00

You might try GTAW with an ac/dc inverter; weld with the ac and the balance control at 95 to 99% time at negative. the small percentage of time at positive provides oxide cleaning & wetting

By 803056

Date 01-12-2011 05:28

My personal experience has been electrical bus bar. The purchaser did not order deoxidized copper bar. It produced more porosity than sponge rubber. When he order the deoxidized copper most of the porosity problem disappeared and other than having to preheat and weld using very high amperage, no problems.

Best regards - Al