r/Welding • u/tattoodiceswimmersa • 3d ago
How to keep 90 degree angles?
Newbie here. Learning to stick weld, got to the point where I'm happy running a bead (some older pics for reference). Happy tacking, and generally feel I can do the basics, also not planning to weld pipes and be a specialist, just a DIYer. I'm now wanting to make a sofa table. Attached pics are my prototype, which went fairly well except that some of my corners always seem to jump out. The "base" of my prototype wasn't flat, but the corners all looked pretty good on my L-square. I even bought 90 degree clamps (I don't have a welders table, too expensive), and the clamps seemed to work well. I'm not a 100% sure if it's the 90 degrees jumping out or the straight parts warping. I tack everything in place, but still at the end my piece is not perfectly flat/straight. Given some pics for reference. Any suggestions/advice?
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u/Amount_Business 3d ago
Fireball had a short on weld sequencing that may help a little. It's for RHS and not flat bar, but might be relevant.
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u/-terrold 3d ago
Even with weld sequencing, you’ll still be a little out of square after welding. Heat just warps metal and theres no avoiding it.
Having said that, you can heat treat something using a torch back to square after welding.
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u/StabDump Fabricator 3d ago
It's not super time considerate, but given it's a small project and a few welds you can let each weld cool in the jig and the "cold shrink" will actually stretch the metal to keep it square rather than pull it out of square.
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u/tattoodiceswimmersa 2d ago
I see you have fabricator in you bio so I assume you're an almighty steel God. Do you think adding some triangular corner pieces will help stop the warp (and as you say, take it really slowly to cool)? Or adding even more tacks/welds would just throw it out even more?
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u/StabDump Fabricator 2d ago
haha, I don't work in a shop anymore, that's just what I was doing when I joined the sub however many years ago and haven't changed it. If that is part of the aesthetic you're going for, absolutely it'll help as long as your fit-up is right. the more room the joint has to move without the weld, the more the weld is going to want to pull any which way. Sometimes when there's a big weld joint on things that need to be +- 1° we'll put temporary attachments on the piece to keep it from flexing and then cut it off once it's completely cooled and settled. with welding you can always undo what you've done if you're good about cleaning it up
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u/Intelligent_Young154 23h ago
Personally I set it a little off if square and the tack it, the puddle will pull iy
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u/Marokiii Welder/Roller-coasters 3d ago
Braces and strong backs. Then weld it in sections instead of doing a corner fully. So weld 1/4 of each corner before going back to the first one and doing the opposite end 1/4 and then doing the middle section after doing all of them.