straightening bent pipe with heat?

[uninformed]

i'm building a tray/roll bar using 40 nb 5.3mm wall chs

i have gone too far on one of my bends. its only about 15 degrees at the moment. i want to bring it back a little, only about 1 degree or so.

can this be done by heating one side of the bend(not using force).

if so what side the inside or outside of the bend?

cheers serg

[bru21]

its easy to pull bends back by hand. just wedge the pipe somewhere (towbar socket etc) and pull. you will be suprised how easy.

Also had a sec to look at your drawing, sorry been flat out.

looks similar to mine except i ran the x to the corner of the biggest square (the bends at the edge) and then the chassis mounts were a foot away from the x at each side. I think the way you have drawn it should be fine as long as it is welded at the x to the shs. It is always hard to compremise designs to allow for little niggley things like chassis! 40nb should be fine, be aware that the thickness makes very little difference to the weight like a matter of kgs per length. the difference between 2.8 and 3.2 is so small i didn't bother using both sizes as i ordered my last tube (like 4 or 6 kg a length i think).

remember to brace your backstays directly to the chassis and without bends to the top of the x / main hoop area as to stop the main hoop bending when sliding upside down

cheers mate

bru

[uninformed]

ok i didn't want to try and bend it back by hand because:

#1 the pipe is 5.3mm wall which i think would be hard to bend.

#2 i didn't want to bend it out of "plane"

so by laying it on the drive way, fairly flat, heating the outside of the bend with oxy and then quenching it with water it worked spot on.

cheers, serg

[OISTA]

Watch for cracks on that bend later on as the steel will have become more brittle from the quenching. Shoudn't be a problem, but if it's going to happen it'll be there

[OISTA]

Another way to straighten bends is grab one end of the steel. Hold so bend is up /\ and tap end your not holding on concrete firmly, (not hard, just firm). This will straighten the bend without twist

[awill4x4]

Watch for cracks on that bend later on as the steel will have become more brittle from the quenching. Shoudn't be a problem, but if it's going to happen it'll be there

Nope, not enough carbon content to promote cracking.
Regards Andrew.