The weld wants to shrink as it cools to room temperature but is restrained from doing so by the adjacent cold base metal.
How to straighten warped sheet metal.
Body files are usually used after another age old process has been used to straighten or shrink sheetmetal.
Heat straightening involves applying controlled heat to a deformed part of steel in heating and cooling cycles until the metal gradually straightens.
Use a heat gun to warm the part of the aluminum you wish to straighten.
Looking for and easy and effective method for removing oil canning in sheet metal or auto body panels.
This process works every time is very simple and wil.
Lay the aluminum object on a flat solid surface like a concrete floor.
To accomplish heat straightening you must apply controlled heat to the proper places on the metal gradually to allow the metal to expand and shrink.
Careful observation of the effects of the heating will allow you to make adjustments to the location and the amount of heat applied to further the process.
That or cut the transom pull the sides together overlapping them mark the extra metal that needs to be cut out and reweld with 2x4 set across the top to prevent the sides from pulling in as the weld cools.
This restraint creates high residual tensile stress that causes the weld to act like a stretched rubber band with the workpiece holding the ends figure 1 for this reason when the clamps that hold the workpiece are removed the base metal is allowed to move or spring.