Welding Tips and Tricks

Good afternoon,

Today I turned down a job that I was unsure I was able to do. I have welded aluminum and fabricated some nice projects for customers, but nothing over 1/8" wall thickness. Well today I was called to go to a carwash and weld 3/8 thick aluminum bracket to 1/2" wall tubing. This would hold a few hundred lb equipment. My machine only goes up to 200amps. Any suggestions? Would helium do the trick?

Anthony

Man, if you're unsure about the work, walk!

I would want more than 200 amps to weld that, even with a preheat. A 50% He mix will help, but I'd also be concerned about the condition of the aluminum bracket. Sitting in a carwash, I'd anticipate a fair bit of contamination having seeped into that piece. Could make for an absolute nightmare of a job

cj737 wrote:Man, if you're unsure about the work, walk!

I would want more than 200 amps to weld that, even with a preheat. A 50% He mix will help, but I'd also be concerned about the condition of the aluminum bracket. Sitting in a carwash, I'd anticipate a fair bit of contamination having seeped into that piece. Could make for an absolute nightmare of a job

I beleive it was new material. What concerns me is that it would be a fillet weld, and that takes heat.

What process, and amps would you recommend?
Would mig be better?

I would bevel the 3/8" material against the welding edge. I would use TIG happily, but I'd want up to 250 amps available to me. With multiple passes (3/32" filler until flush, then a 1/8" cover pass) I'd be confident in the weld. This would be beveled on both edges and welded on both sides.

I would turn the freq down to 50-60Hz, balance up to 75% on my machine, and crank that sucker up to FULL AMPs. You won't need the full amperage once you put a pass or two in as the part will be very hot. But a preheat, and full romp will get your puddle going.


I've used this method (above) a few times on Jon boat gill brackets. Welding 1/2" angle to 5/8" brackets. I used MAPP for a preheat, a no fill pass, then came back and smashed it with a full pedal and some filler. Waiting for the part to cool so I could lay another pass was the biggest trick. I had the luxury of doing this on my fixture table, in my shop, not in position in a carwash. I don't envy you-

cj737 wrote:I would bevel the 3/8" material against the welding edge. I would use TIG happily, but I'd want up to 250 amps available to me. With multiple passes (3/32" filler until flush, then a 1/8" cover pass) I'd be confident in the weld. This would be beveled on both edges and welded on both sides.

I would turn the freq down to 50-60Hz, balance up to 75% on my machine, and crank that sucker up to FULL AMPs. You won't need the full amperage once you put a pass or two in as the part will be very hot. But a preheat, and full romp will get your puddle going.


I've used this method (above) a few times on Jon boat gill brackets. Welding 1/2" angle to 5/8" brackets. I used MAPP for a preheat, a no fill pass, then came back and smashed it with a full pedal and some filler. Waiting for the part to cool so I could lay another pass was the biggest trick. I had the luxury of doing this on my fixture table, in my shop, not in position in a carwash. I don't envy you-

I guess its a good thing I didnt take the job. Are you saying 250amp with helium? Dam. I need a bigger machine.

Guess it really doesn't really matter now, you had to turn down the job, but in the future, do you have a MIG/spool gun available? I'd prefer that over TIG for that size material, and that type job.

ljdm1956 wrote:Guess it really doesn't really matter now, you had to turn down the job, but in the future, do you have a MIG/spool gun available? I'd prefer that over TIG for that size material, and that type job.

Ive never used a spool gun. I have a esab 215ic which I can attach one to.

It’s true Spoolguns can do the work, but you’d better be darn sure you have it setup right. With TIG, you do get a better opportunity to insure penetration and fill.

You wouldn’t need 250 & 50% Helium to do that job, but it sure wouldn’t hurt to have both. The biggest concern from my perspective is the 1/2” tubing. Welding to it, you have little to notrol over the penetration, so you have to blast into it then stick the 3/8 to that. The 3/8 is the easy part, beveling and so on. But insuring a solid weld into a tube you may not be able to see into, that’s the trick. And the concern.

cj737 wrote:It’s true Spoolguns can do the work, but you’d better be darn sure you have it setup right. With TIG, you do get a better opportunity to insure penetration and fill.

You wouldn’t need 250 & 50% Helium to do that job, but it sure wouldn’t hurt to have both. The biggest concern from my perspective is the 1/2” tubing. Welding to it, you have little to notrol over the penetration, so you have to blast into it then stick the 3/8 to that. The 3/8 is the easy part, beveling and so on. But insuring a solid weld into a tube you may not be able to see into, that’s the trick. And the concern.

And if the weld ever cracked and fell on a car, it would be a bad day for everyone.

Ant428 wrote: And if the weld ever cracked and fell on a car, it would be a bad day for everyone.

Yup, always a concern when welding anything that involves people. Thus, why I would never do a welding task I'm not 110% experienced with. I hate to walk away from money, but the risk is never worth the reward in my book. Besides, there's always another competent guy/gal out there with the right experience to do the job. Better he/she get paid then me get sued.