Welding distortion

The welds shrank as they cooled. Try peening them to stretch them back out. The work'll go faster hot, but doing it cold is safer and less prone to surprises. A good heavy dolly to back up your hammering is a must.

Are the two stable states warped with the corners out of plane?

I suspect that the welding heat expanded the sheet & the welded-in patch locked it in the expanded state. There are 2 methods that I know of to shrink metal:

1. with a torch, heat a spot of the expanded metal to orange (red?) hot & immediately quench with a wet rag. Repeat as needed.
2. using a soft mallet (wood, plastic, rawhide), beat the expanded metal with a steel backer. The key is that the mallet is softer than the backer.

So, if it shrank, do as Ned says. If it expanded, do as I suggest. If you guess wrong, it will make things worse.

Good luck, Bob

I would bevel the plug and the hole so the plug does not fall through the hole. I wounld then spot the plug from the back on three points, grind the spots flat and then sand the front. A can of primer surfacer and a sanding will cover up any flaws.

John

Oops, I did it again!

I have 3 electrical cabinets that I have emptied of all the useful bits and would like to make them into lock-up cupboards. They are 2 mm. mild sheet and stand about 6 ft. high and 3 ft wide with a depth of about 9 inches.

The doors are having a folded and welded edge for strength, but because there were a lot of switches and lights etc. there before they left a lot of holes which needed to be filled. I made some disks of the correct sizes and thickness and MIG welded them in the holes. This was in the first door. Smashing, all I needed was to grind down the welds smooth, a bit of filler and paint. Oh no! The panel has now got two stable states, both wrong. The panel is distorted and I am dismayed. Is there any way I can relieve this and make it flat again?

Does anyone have a solution? I would be very happy to try anything.

Thanks and regards George.