[nova_70_383]

i have a 18" by 4" wide by 1/4" thick copper plate. it has 50 holes in it. i want to weld up the holes and have it machine flat, so i can use it as a backer. will copper warp if i weld one hole at a time? i have 12 gauge wire i was going to use as filler rod. thanks for any help!

[Otto Nobedder]

I doubt it will warp. Copper is very malleable, and the heat required to weld it will anneal it, as well. Maybe a good preheat and a low weld amperage will further reduce the chances. In the worst case, it should be easy enough to beat it flat with a soft-face hammer.

Steve

[ajlskater1]

This is kinda of topic, but I was wondering what is the best filler for welding copper. I have welded some copper chill blocks on some fixtures using silcon bronze but that kinda sucked was really hard to get the rod into the puddle before it just balled up on me.

[weldin mike 27]

Hey there,

I have seen a video of a guy welding copper with stripped electrical wire as filler. He did stress though that it shouldn't be used for critical purposes but it worked well.

http://www.youtube.com/watch?v=QjKu_Mm0Hp8&feature=plcp

Mick

[ajlskater1]

ya after I saw this post talking about copper welding, I went on youtube and looked it up and saw that video. I don't have a project in mind or anything just trying to gain some more knowlegde, I think I am going to shear some thin strips of copper and use that as the filler and try that out.

[nova_70_383]

thats what i was using, stripped wire. i welded one hole to test it. after i sanded it off its a match color wise. the bars i got were buss bars. any electrical copper is usually 99% copper. the same for electrical wire. the filler rods ive seen were not 99% copper. at my job i weld bronze with copper-trode rod. the rods are made by harris. they are real tough to deal with compared to copper-trode. silicon bronze rod melts really easy and i can see why you would have trouble getting to the puddle. copper melts at 1900 plus deg F. besides for a color match silicon bronze is more yellow then copper color. im just using this bar as a backer like jodi's videos!

[ajlskater1]

ya like I said I don't have a project or part that I am working on, I just had trouble with the silcon bronze in the past and was just trying to gather some knowledge so in the future if I have to do some actual copper parts I wouldn't be lost.

[RedIron881]

Any time I've welded copper I added Helium to the mix. Had a job that was 12 1/4 inch copper pots (500 lbs each). We used 1/8 inch bar stock that where the same material so they matched. The really crappy part was grinding the welds and putting a directional grain on them... I was green for months! Ha ha! Pre heating and adding Helium works great though.

http://www.ckworldwide.com/tech-3.pdf

[ajlskater1]

I have always used a preheat in the past on like 1/8 and thick copper, but never tried the helium will have to play with that.

[nova_70_383]

helium is a great idea, but in another post i put up there is a helium shortage. i cant get any for sure for the 2012 year. i will pre heat. helium makes perfect sence though since it is a hotter arc.