Welding help needed

I am trying to make some steel "L" brackets. They are 10"x16" made from 3"x1/2" steel flatstock. I clamp the parts in a jig to hold them square, but when I get the welds done they are no longer square. They are pulled in a couple of degrees. I am using 7018 rods with the welder set at 115 amps. What am I doing wrong? Can I get the brackets that I have already welded to square up without completely grinding out the welds and starting over? Thank you for any advice.

that is a easy mistake, gonna be tough to get the others straightened , but the others, still put in gig, and tack weld both sides, do not solid weld one side then the other , if you do the heat will pull the steel, after tacking both sides chk for squareness, if good weld it up, hope this helps

Heat warp. That's a common problem when welding, particularly with a stick welder.

You need to clamp the pieces to a jig or something that will hold them perfectly square both while you're welding and until they've cooled off.

A forge, a hammer, and an anvil are all you need to square the brackets. Armand

Start a few degrees wider than 90 and weld a pass on the outside first then weld the inside and let it coast in. Even in a jig it can still pull some.

parissprings-did Turnback get up much after the last rain? Spring River was running a little high at Bowers Mill

I do like Farmer 656. Do part of one side then go to other then finish first. if it were just a one off I would tack a scrap across at the ends then cut it off after, but for multiples a jig would be better

Yep you have to tack weld in all corners before you weld it tight. Tack in an X manner to keep the pull form knocking it out of square

Old gave you the right answer. Tack first then weld. Works for me also. Great tip.
LOU

Also, if you start welding from one edge and just go all the way across in the same direction non-stop it will squeeze (shrink) more at the end that you ended on than at the end that you started on. You can compensate somewhat by 'back-stepping' and stitch welding. You start about an inch from one side (or edge) and weld back towards the edge, then your next stitch will start an inch from the start of the first weld and go back towards the start of the first weld until you get to the first weld. And so on till you have welded all the way across the piece. You would use larger stitches for longer welds.

You can also compensate some if you don't want to go through all that by making your root gap a little smaller on the edge you are going to start welding from so that when it all shrinks it will (hopefully) pull it square.

If you want to stop it from bowing up across the weld, as well as the previous suggestions about not welding all of one side first, you can put a thin shim under the weld area and clamp the piece down so that it is 'pre-bowed' a little and (again hopefully) the bowing caused by the shrinkage of the weld will counteract the bow you deliberately caused with the shim.

It is a bit tricky - even with tacking everything because the tacks themselves will pull and shrink and the first ones always pull more than the next ones and when you weld over the tacks they will melt into your puddle and then effectively be doing nothing. One thing I used to do that seemed to work at times was to put a little piece of 3/32 or 1/8 rod a bit in from each end of the root, make sure they are in place then put a good tack (at least a 1/2 inch) in the middle. The tack in the middle tries to pull the joint together but can't because the bits of rod are preventing any movement. Then I could tack on the ends, outside the bits of rod and nothing would move because the tack in the middle and the bits of rod are holding everything in place. YMMV.

HTH

How flat and square do you need them to be? If the stock is hot rolled steel you should be able to machine the faces to meet tolerances.

Tack them up, cut a brace from some scrap to tack on the outer legs connecting both tack the brace pretty heavily. Weld up joint.The joint outside first, then the inside. Let it cool completely, grind the tacks off the brace and check for square. Adjust by heating the joint opposite the way its out or a few smacks with a hammer.

That is how I do things I want to keep square also. Gig blocks on the outside and tac solid or bar stock/angle iron temporary gussets for the inside to hold it square.

I think most are over thinking this. If I was doing it I would weld it, check it for square then if it needs adjustment put it on an anvil or something and give it a whack with a hammer. Start with little hits til you get a feel for what you need, but that will be the quickest way to get it right. If you have any fabricating experience you should be able to get it right fairly easily. In my experience holding a perfect 90° in a situation like that will be much harder than just adjusting afterwards.

yes cobroller turnback was up but I have seen it worse.

Have a hydraulic press ? Let 'em warp and press em straight.

I use an 18" I beam 6' long with a 1 1/2" thick x 14" wide flange as a welding table. When fabricating parts that must be dimensionaly correct, I clamp at 4" intervals, tack, then weld one side, grind flat, flip, clamp at 4" intervals, weld the back side, grind flat, then check dimensions. A heavy welding table like I am using takes a lot of distortion out, but sometimes still may require final adjustment. Mel

When I worked in a welding shop we got a job making cheese curing racks. We built a jig to hold the pieces but the rack came out off square. Then we rebuilt the jig off square & they came out just fine.