Welding Tips and Tricks

I am in the process of making some track stands for my bandsaw wood mill. I am making some really simple box frames out of 2x2 16ga square tube.

Because I want the tracks to sit on top of the frames with full support, I made the top and bottom "ladder" frames first. Now that they are ready for the end squares to be welded on, I find that they have twisted even though I tried to be careful. The best one has a 3/8" twist in 8'.

So, not being a professional, I am not sure what my options are. Obviously, I could try to twist them in the opposite direction. The problem with that would be anchoring one end.

Is there some magic I could use instead?

Andy

Irving, TX. Epicenter of the Metroplex!

Hi there,

I hate when things twist, they are usually very hard to "un-twist". even for professionals. I have toyed with the idea of parking the car on one end to anchor it. Good luck with it.

Mick

Only luck I've had is by useing a hydraulic press. If you can figure out the exact areas it's twisted at some times you can counter bent in small increments over the area. I.E. if there is a a 1ft area were the twist is the worst I would mark out a series of bend over that area. But on tube that thin it's going to be difficult because it may spring out of shape in other areas.

OK so this is just in fun. Question; if you just saw elm on a crooked mill will it come out straight?

Straightening things after welding is often more difficult than the actual welding.
At work I mainly use flame straightening if things get out of spec.

When you say twisted, I'm guessing the problem isn't just parts being out of square, but the thing is pulled in multiple directions?

In that case I turn to the big torch, a long lever and a pocket full of money for the swear jar

It's not easy to help with a thing like this, but I'd say look into flame straightening, and give it 10 more tries than you think it's worth. It might be an opportunity to learn something

All,
I pretty much did all of the above. I used the bumper on my 1990 F350 as a fulcrum point and got a 2x4 to untwist the good one. The bad one I straightened using a hydraulic car jack to position the piece, clamped the other two dimensions and welded it up. Then I peened the crap out of it with a 3lb sledge to "ring off" the internal stress. Worked great!

Irving, TX. Epicenter of the Metroplex!

Glad it worked out for you. I must say that figuring out a weld sequence is a learned experience. I have spent hours experimenting with various clamping, tacking, and welding sequences to minimize warpage. One -offs are another story and it pays to clamp more than you think and weld short sections equalizing weld stress as you go. Sometimes we resorted to tack welding a weldment down to a steel table to keep it square and then heating it up with a rosebud and allowing it to normalize after welding before cutting it loose and grinding the tacks off.

It's a never ending problem. Welding with thin or small parts that can't take the heat buildup or even welding too much at one time is something that is always gonna have to be in your head. The battle with warpage is always there.

Diesel wrote:It's a never ending problem. Welding with thin or small parts that can't take the heat buildup or even welding too much at one time is something that is always gonna have to be in your head. The battle with warpage is always there.

I found this out during one of my first projects, my welding cart. I made the top and bottom box separate then planned to weld the uprights last, after everything was good....well it wasn't ! It twisted so I ended up clamping two corners elevated up on 2" metal blocks, a back left and a front right corner. Then I put a large C clamp on each of the "free floating" corners , the corners that are diagonal to each other. I squeezed the clamps till it pulled the box all back into one plane, At that point I got out the torch and heated the welds at the corners that were clamped onto blocks. I never heated them to glowing, just til I saw some color change. This made it better, but not completely untwisted. At that point I tightened the free floating corners til they were about 1/8" beyond where they should be. Heated again and that did it.

I just got done fabbing up a mobile base for my mill. This time, I welded shorter runs , moved around more, back stepped, welded in opposite directions and welded my 45 corners from the inside outward . A blessing in disguise also helped. Last thing I welded, I noticed my 20 torch getting warm. After inspecting everything I find I've got a fungus growing in my cooler reservoir ...still flowing but not that good so I had to pull out my 26 torch ...at 250 amps I had to pause more and I think it helped because the whole thing stayed square and all in one plane .