I know the tube bending thing has come up a few times before, but maybe you guys will tolerate one more. I've built a ladder style frame 5x8 for a teardrop trailer and one of the 2"x2"-8' tubes has bent. A line stretched from end to end is out almost 1/4" in the center. This makes one corner up almost 1/2 to 3/4 of an inch when it is laying flat on the table. Should I try the heat on one side trick? or just block the corners and jump on it? I'm afraid it's going to look like a bananna if I go to far with the heat, but I'm not sure trying to bend it with force will do what I need. I'm about an hour away from making shelving out of it.
Do I heat and cool quickly with water or will it straighten by letting it cool slowly? And can I do it in small increments until I get what I need? I've been a sheetmetal fabricator for 15 years, but this tube stuff is giving me a headache. Thanks.
Heat is what bend it, heat wil get it back... Do it very carefully by heating one dime sized spot at the time on the outside of the bend, and cooling it with a wet rag right away. The outside is the "long" side, and carefully shrinking it will straighten it. Nothing will seem to happen at first, untill you get frustrated and overshoot. Take your time and measure a lot.
I tie some string to the corners at one end and cross the strings and drape them over the other end with some weights tied to them to keep the strings taut. that way you can see from if they touch or not, (or "bend" each other) if its twisted or not. Like said above, Heat on the outside of the bend you want to straighten, if you watch the cross strings, the gap will get bigger when you do this but when you cool it, it will shrink more than it expanded. If you don't want the mess or rust from wet rags, just cool it with compressed air. It may be that it got a bit off at th corner welds, still, heat on the outside of the bend. but watch out there that you don't shrink it out of square.
The Jalopy Journal
