One of the big tricks is to know how much a weld will distort, and in what direction. That way, you can pull out of square joints into square, and be able to predict what a weldment will do when you light up on it. That said, minimizing heat input, and lots of clamping and fixture will help. These options are not always available, so being able to tack in a way that the joint will be correct AFTER the weld is a good skill to have.
This is an excellent tip.
Here is an example:
Say you have two pieces of 1x1 box tubing, and you are going to weld them into a "T"
Your first thought is to weld inside the corners, where the pieces meet.
If you do it that way, here is what will happen:
Here is your "T" union, laid on its side so I can demonstrate this with the symbols on the keyboard:
—l
If you weld in the inside corners where they meet, you will build heat in the middle of the intersecting piece, and it will pull in toward the weld.
—)
So what you do is weld on the SIDES of the two pieces, where they come together, rather than in the corners.
Not sure if that makes sense, but it will the first time you weld two pieces of box tubing together.
Welding makes metal grow.
You control the growth by "growing" it in the opposite direction, and it should come back in to square.
Good tack welds help too. And of course, as others have said, clamping.
-Brad
