How to Determine If a Panel Can Be Soldered?

STEP 1: remove all coatings from the surface to bare clean steel

STEP 2: heat the area with a propane or MAPP gas torch

If the panel sinks as heat is applied, it should not be soldered. The way the panel reacts to heat indicates the stresses that were imbued into the metal when it was manufactured. Exposure to heat can actually produce stress fractures in some steels, so be sure to only use a sufficient amount of heat to melt the solder.

Avoid soldering perforated panels because the flux residue on the back of the metal will cause accelerated corrosion. This problem usually shows up as a swelling in the repair area a few months or years later as the forming rust underneath expands. For this same reason, seams that are only partially welded should not be soldered. Seams should be completely welded to prevent acidic flux residue from becoming trapped.