I have a project to build an aluminum door for an aircraft. It is an airstair door. Approx. 4 ft by 5 ft. It is made up of many sheetmetal parts all 6061. All the same thickness .063. Some parts will be bent to shape on a brake. Others will be cold formed to shape using a shrinker stretcher. All the parts will then be put in a jig fixture for welding, which will result in essentially a shell. The problem that a previous manufacturer had was warping.
I saw at one time a welder first tacking together, than welding little sections (approx 1 inch) at time at opposing locations. I think it was for allowing even heating of the aluminum. I would think with the addition of "clamping until cooling" that this might reduce the warpage.
Is this correct?