a good test would be to hold a lighter to it for a second, if the whole thing goes up in flames, don't use it. if it just sears it only a liitle it should be fine. 12V tends to get hotter than 6V. If you're using an ec-90 you should be fine b/c that thing doesn't dissipate any energy in the form of heat. I'm not sure if the pick and pluck foam is flame retardant. I doubt it is. you can find flame retardant foam at just about any craft store.