Welding Tips and Tricks

Building a welding / fab table and managed to f up a little bit. frame is 1 1/2" 11 guage square tube. six-legged box design with 1' x 4' x 1/2" plates on top, with 9" spacing between them (overall size is 4' x 8'), frame inset 4" all the way around. Anyway, middle leg on one side was warped out while I was tacking the frame together, so I used a winch strap and hammer to correct it. thought I was ok (or close enough to ok to fix as I kept framing it together). Have most of the frame together except for 4 of the top cross pieces and realized that I over-corrected my "adjustment" and need to pull the one side back out about 1/8" without moving the opposite side. I know a jig fixture would be ideal, but if I had a table and jig setup, I wouldn't need this table I'm building.
So here's my question: any tips on heat-bending the bend out with an oxytorch without warping the frame up or down or some other direction I don't want.
The whole thing is flat and square (well, within my acceptence anyways...garage floor ain't dead plumb. it's all +/- 1/16th" and fraction of a bubble) except this one leg needs to lean out just a bit.
Any ideas would be most welcome.
thanks

If it could be done, I would flip the table over with the side you want to adjust up, get a nice long piece of pipe that fits inside the leg you need to adjust and use the pipe as a breaker bar to pull the warp out. Leverage and muscle should be able to fix it. You will probably have to overcompensate a little bit and let it fall back into the right spot.

You might even want to consider getting rid of the middle legs altogether. They could give you lots of leveling problems and you might not even need them on a 4 x 8 table. But that also depends on how heavy the jobs are that you do.


Other Steve

I don't have a pipe that would work, but I like your idea. Flip the table on its side with crooked leg up, and gently force the cross pieces into place. The side on the floor shouldn't be able to give, so the side in the air will have to. No heat required, so no chance of inducing funny warpage. Thank you.

I run into this a lot being I build a lot of one off stuff that creating a fixture or jig for is impractical. I compensate with strong backs clamped to the work piece. This can consist of a couple pieces of angle iron doubled up and make shift trusses using other rigid extrusions and shims to add compensatory stresses in certain areas. 11 gauge is easy to correct. You may find that you can set the top on the floor upside down and while standing on it, move the leg wherever you want just by pushing on it or whacking it sharply with something with some heft to it. If it's the top frame you need to tweak, you could clamp some angle on the side you want to keep as is, and jack against the side you want to move with something as simple as a bottle jack from an automobile tire kit, or even driving a 2x4 that is slightly larger than the finished size or something.

Free building things without jigs certainly has challenges, but typically, if something starts out in the right place it can be put back reasonably. Every time I get a drop of some really straight 1/4 wall 2"x2" angle, I-beam, or anything like that, I stash if for makeshift jig parts and strong backs. That, along with an ample collection of R-11's and scraps of 1/4" flat bar become invaluable.

In place of a middle leg, if you really need the extra support, don't discount a truss instead. It doesn't have to be bent tubes like this. Even a girder between legs and some nipples between it and the top will add a considerable amount of strength.



On this 12' table, they opted for a middle leg on the rear to save cost, and a truss on the front. I had to build pre-stress into it because it's only 1-1/4" sched 40 aluminum and will have some weight on it. Adding the leg in the middle and fully welding it would kink the top so it had to be backed up with a strong back while welding, as did all the oval nipples on the front truss or it would have looked like a stick of bamboo if left to fly by itself during the welding, or even tacking stage. As it was, I had to still do a considerable amount of correcting both during and after the fact. The fab table in this situation wasn't really much of a help other than to hold it up higher to weld it easier.



If you notice in the photo, some of the legs are still crooked. They didn't start out that way. I can't scratch the metal either, so it takes creative tweaking and it would, even if it had been built in a fixture.

You may consider adding adjustable feet to your table legs any way. I have rarely found a floor or table that match. The fab tables in the above photos have them. That concrete floor there is awful. 1/2" difference in 8 feet in some places.

that's some nice stuff you're doing there. Thanks for the info too.