Coating Military Medals

Q. I have inherited my grandfather’s and father’s World War I and II medals and badges, and I am curious about powder coating them to preserve them for display. Years ago, my father tried lacquer (which failed miserably), then nail polish, which lasted for a few years, then peeled off, as well. They are not particularly valuable, but I would like to have them powder coated clear (after polishing, of course) so they would look good for home display without having to polish them every week. Will the heat of curing them (around 400°F, I understand) damage or discolor them? Most of the badges are brass or silver (some with soldered fittings on the back) and several of the medals are bronze. I know that the heat of soldering brass will usually discolor the brass, but would the heat of a powder coating oven be sufficient to melt the solder or discolor the metals? N. M

A. I will defer any comments on powder coating military medals to Nick Liberto in his Powder Coating Clinic. Instead, I will address preserving them using liquid coatings. These can be applied and cured at room temperature, negating any chance of tarnishing and de-soldering. Military medals, which are primarily bronze, can be coated with acrylic lacquers or acrylic modified polyurethanes. These coatings, which must be applied in a clean area with proper ventilation, can be brushed, sprayed or dipped. But first, I must say, those medals are valuable because your father and grandfather earned them through their actions.

The general rules for applying any coating are: 1. The surface must be clean, free from oily soils (polishing compounds) and particulate matter. 2. The painting area must be clean, free from air-borne particulates. 3. Solvents and coatings overspray must be exhausted from the painting area. The coatings (lacquer and nail polish) applied by your father, may have adhered, had the surfaces been properly prepared.