No pro here, but I had some problems with stuff setting, sometimes it would set, just took a few days, other times it stayed gummy, then I took it all off, probably paint stripper or solvent at this point.(if it didn't set solvent works fine & is a little less harsh then the stripper)
oh yea is this on bare metal, if there's a coat under it & that set, the solvent would probably just remove the gummy stuff, which is a plus. Rich.