Heat warping box section

[Simon.b]

I make rock and roll beds and have to make the base frame. I use 25x25x2.5 and 25x50x2.5 box section.
For some reason every so often one is warping and completely throwing the base out. I’m not doing anything massively different in the way I weld them and I had one today and it drove me fecking mad!
What’s the best way to keep the box cool? I don’t have an air line either.

 

[Tigman]

Hi Simon can you show us a pic of what your doing ? make it easier to understand !

 

[Simon.b]

Hi Simon can you show us a pic of what your doing ? make it easier to understand !

 

[Simon.b]

I done it in stages, so did some on one let that cool then some on the other and so on. I used my clamps and my 90 corner clamp etc.

 

[Tigman]

is it bending where you join the 50 to the 25 in the middle ?

 

[Simon.b]

is it bending where you join the 50 to the 25 in the middle ?

Either there or on the 25mm legs. I’m wondering if because I’m letting it cool and not doing the same on both sides that perhaps that is what’s doing it? I don’t have a sequence that I do but perhaps I should?

 

[Paul.]

On lightweight material like that you can run your welds vertical down, you will move much faster and so put less heat into the joint, so reducing distortion.

 

[Tigman]

I think youre going to have to clamp the frame down to a flat surface or clamp a thicker section underneath and weld , have you a table the size of the bed or are you working on the floor ?

 

[Simon.b]

On lightweight material like that you can run your welds vertical down, you will move much faster and so put less heat into the joint, so reducing distortion.

Excuse my stupidity here.... I make the side on their own so weld flat I then put the cross bars in etc. Do you mean when I weld the vertical joints after?

 

[Simon.b]

I think youre going to have to clamp the frame down to a flat surface or clamp a thicker section underneath and weld , have you a table the size of the bed or are you working on the floor ?

I have a table but half is jig for the top of the bed. The other half I use just as my bench when welding the base up.

 

[nickk]

If it’s as you state “every so often”, could it be that every so often you have a bent piece of box,or are you being inconsistent in your procedure?

 

[Simon.b]

If it’s as you state “every so often”, could it be that every so often you have a bent piece of box,or are you being inconsistent in your procedure?

Inconsistent with my procedure

 

[nickk]

Maybe. Use heat sinks,in the form of heavy bars/plates on the back surfaces prior to welding,make sure the fit of cut lengths is accurate,no forcing or gaps on joints.

 

[Morrisman]

Inconsistent with my procedure

Depending on how many you build, couldn’t you follow a set assembly/welding procedure, take notes, see which one doesn’t produce distortion?

 

[WorkshopChris]

For some reason every so often one is warping and completely throwing the base out. I’m not doing anything massively different in the way I weld them and I had one today and it drove me fecking mad!

Are you consistently keeping the material in the same direction (either weld seam up or down) or just random orientation? The material will behave differently one way to the other, due to tensions set within during the manufacturing.
Might be worth keeping an eye on it to see if it makes any difference to how it distorts.

 

[Arclikeharrypotter]

If you fit up isn’t spot on and your dealing with gaps then the weld will cool and cause the frame to warp slightly. Get the fit up and angles spot on and the heat shouldn’t be much of an issue.

 

[Jim2007]

You can clamp large blocks of scrap aluminium to the underside of the plate/box your welding, and this will work as a heat sink. Aluminium is far better than steel as it is far more heat conductive.

Hope it helps

Jim