Columbia coatings supplies a filler called lab metal..I haven't tried it (yet) but i've heard good things about it.. lead might work, but I doubt it.
I'll add to this as i've been playing with them all day.. The super mirror black is awesome..looks three feet deep even before the clear..and i do recommend you to clear coat them.. the chrome powder is based on a leaf quality aluminum, and MUST be cleared over..otherwise the aluminum starts to turn grey..icky. i'll post this pic, it's the only one i've got at the moment, i'm gonna mess with some candy colors tomorrow... any questions just PM me..I might miss it otherwise... Lloyd
Lead under Powdercoat does not work weel. I tried it and the lead Sagged. I should have used the "All Metal" filler that Eastwood sold. I peaked the center bar of my 36 Ford Grill, I used the Lead to blend the round bar into the original center bar. I ended up shooting the grill with a urathane after I fixed the unsitely sags. Now I know better. LEAD is good but does not alway work.