[sportster]

I'm arguably a novice welder, but I do ok doing aluminum welds 4"-5" or less in length. A friend asked me if I could do multiple 18" welds. This left me wondering how to approach such a task.

Background:

• 1/8" aluminum plate - outside corner joint - 18" long welds
• think a box with 18" welds
• sides need to remain straight / parallel, and corners at 90 degrees when done

Machine set up:

• 150A (on the pedal) should be plenty
• AC Balance around 65%
• 120 HZ
• 4943 filler rod 3/32"
• 3/32" tungsten - 2% lanthanated
• #6 or #7 cup

I'm anticipating distortion may be a problem. Yes/no/maybe ?

What's the best approach to eliminate / minimize distortion ?

• 4-8 tacks ?
• clamp chill blocks behind the joint & just weld it out ?
• skip weld the joint ? e.g. 4 welds @ 4.5" each. Completely cool down the part between welds ?
• some or all of the above ?

Maybe, I'm overthinking this.... and I should just get some 18" test pieces and try it. a.k.a. see what works.

Given I'm an experienced novice (whatever that is).... what are your thoughts on the correct approach to this task ? Thanks for your time.

[Toggatug]

It's not as bad as you think with alum, 1/8 thick is pretty forgiving I find.

If possible I clamp up to a piece of heavy angle stock and tack, I'll leave the angle clamped up if the job allows, most times though if I'm doing open corners on 1/8 it means I'm making a tank of sorts and can't clamp, can't recall any jobs I've had issues with warp.

my amps are set @140 for open corner 1/8" and really only full pedal for the first few dabs then it's a very quick back off to avoid blowout.

Biggest thing I found tricky for a longer weld is getting used to sliding your hand VS having it hard propped and using wrist/fingers for your shorter travel.

Just remember don't death grip your torch as it seems to cause your hand to not slide the same for some reason or other.

But like you said, best way is to just do it and see what works for you. Nobody does it perfect from the get go I bet, those that say they did just aren't being honest with you or they forget their beginnings.

[cj737]

Clamp some angle stock inside, tack at the end and middle of the run. Then weld it out.

1/8 ally sheet WILL warp and distort, without question. You need to ensure you have it fully clamped down before hitting it with any heat.

[tweake]

Machine set up:

• 150A (on the pedal) should be plenty
• AC Balance around 65%
• 120 HZ
• 4943 filler rod 3/32"
• 3/32" tungsten - 2% lanthanated
• #6 or #7 cup

I'm anticipating distortion may be a problem. Yes/no/maybe ?

i would use 70-75% ac balance, depending on how dirty the metal is.
a #4 or #5 cup would be better.

distortion, it depends on size and how exact does it need to be.
if its just a joe blogs box then a little bit out won't matter. if it needs to be precise, thats a different ball game.

[sportster]

Thank you all for the comments / direction.

I hope to pick up the package late this afternoon or tomorrow. We'll see what it "REALLY" consists of when it's in hand. Lol.

I'd like to think I know my limitations but willing to push them. Some strategic tacks and clamping angle stock as chill blocks should work. I can do that. I'll practice on a few test pieces & see what develops.

Ideally, I'll have a few decent pics to share when done.

[cj737]

The advantage of 65% balance is you’ll spend more time cleaning the oxide layer so less amps are needed to weld with. I like your settings because they’re similar to what I use as a standard for 1/8”/11 ga ally sheet.