ben206•16d ago

Tube sheet welding used to take me 3 hours, now I do it in 90 minutes

I work out of a shop in Gary, Indiana. About 6 months ago I switched from using a standard purge setup to a homemade trailing shield with a copper backup bar. The first time I tried it, the welds were cleaner and I didn't have to stop for grinding. Now I can knock out a full tube sheet in half the time with way less rework. Has anyone else built their own backup bars that gave you a big jump in speed?

3 comments

3 Comments

ray18916d ago

Man that copper backup bar is the real game changer right there. I did the same thing about a year ago and it cut my post weld cleanup time by more than half. The heat sink action is just so much better than the standard steel bars we were using before. What I found really helped was machining a slight groove into the copper bar to let the purge gas flow through more evenly across the whole joint. I tried a few different groove depths and settled on about 1/16 of an inch deep with a 1/4 inch wide channel. It made a huge difference in getting consistent root side coverage without having to fiddle with the gas flow as much. I also started using a second small copper block on the backside of each tube as I work my way across and that stopped the warping issues I was having on the thinner wall tubes.

spencerm4615d ago

@ray189 that groove depth thing is a pain to dial in, I messed up my first one too and blasted through half a tank of argon before I realized it was too deep. The warping fix with the second block is smart, I've been using a chunk of 1/2 inch copper bar just laid on the backside and it helps a ton with thin wall stuff like 0.035 wall tube.

the_jason15d ago

Bought into the whole "just get good with a standard setup" thing for years, figured all those fancy backup bars were just a crutch for guys who never learned proper technique. Finally borrowed a buddy's homemade copper bar last fall and it made me look stupid for waiting so long. That groove trick you mentioned is key, I machined mine a little too deep at first and it just wasted gas before I got it right. Honestly kind of embarrassing how much time I wasted grinding down weld bumps that a copper bar would have just prevented in the first place.