Can You Weld Copper Pipe? / Welding Copper Pipe With Oxy/Fuel.

[@mattieb3152]

Interesting. Im setting up to run some copper welding trials very soon. I want to weld 65mm Kembla copper pipe at a 'T' joint for a homebrew beer font. I dont want crappy looking braze joint ... instead ill try a (possibly/likely) crappy weld joint!

[@hendonburgism]

Thin copper tubing and thick copper plate were once welded all the time via autogenous oxyacetylene neutral flame welding and the (lindweld process), not only brazing soldering. You have to preheat evenly and keep the parts you aren't welding insulated, coat it in brazing/welding flux to prevent oxidation (this goes for just about everything other than low carbon steel) and use a bigger size tip than you would use for welding low carbon steel. The best method (according to an 80 y/o book)for welding with filler is to go through the same steps after chiseling a 40° v on the joint itself and use a phosphorus copper rod (although it also mentions using pure copper wire for articles that don't need to be at a certain standard. Typically the copper that was used at the time was much less pure and like every other metal, it was incredibly easy for an unskilled oxy/acetylene welder to do incorrectly.

[@brendanedwards5859]

BRUH -- ya I'm trying to build an all copper frame -- no solder

[@lajoswinkler]

If there is a filler, it's not autogeneous. Autogeneous has no filler. Just two pieces' edges being joined by mutual melting. Autogeneous is not a synonym for gas welding.

[@janettewelsh2165]

That copper tube does not contain any steel. It's almost pure copper just like your filler wire. The extra strength you are talking about comes from the cold forming process in the manufacturing of the tube itself. When you heat it to weld it you will anneal it locally and soften that area.

[@janettewelsh2165]

What you are attempting is in fact an autogenous weld. Your filler material will be as close to identical to the tube material. That is the definition of autogenous. TIG welding these two parts would be your best option.