Assembling Parts Before Electrocoating

Question:

I have heard that parts can be assembled before electrocoat. Is that true and what are the limitations? M.L.

Answer:

Yes, parts can be assembled and then electrocoated. Some advantages are labor savings, usually better line density (compared to coating the parts separately), ready to ship after coating, no touchup of defects caused during assembly and added same-color coating of fasteners (bolts, nuts, rivets, screws, etc.) used during assembly. Sometimes the plating of fasteners or components can be eliminated since the electrocoat will provide similar corrosion protection.

There are several limitations that should be tested prior to committing to pre-assembly. “Bleed-out” similar to that seen when parts are welded or hemmed may result. Threads of fasteners will be coated after assembly and could make disassembly more difficult. While “loosely assembled” parts are coated between the parts due to electrocoat’s exceptional throwing power, if no space is provided between parts, some bare or very thinly coated metal will result. Hinges can be a problem because the electrocoat will coat into the barrel of the hinge. On very light gauge hinges some damage could occur when the hinge is “broken” (flexed the first time) after coating.