Originally posted by rherrell
Eric, if you're talking about bullets maybe this will help. Don't put the powder on real thick, turn your oven down to 350 and just leave it in for 8-10 min..Also, get your powder from Columbia Coatings. I had the same problem and when I did all of the above the problem went away.
Is there something about the Columbia powder that protects the copper against heat discoloration? I find that I get "bronzing" (for lack of a better term) even when I put an uncoated cartridge in the curing oven for 8 minutes at 350(+/- 10) degrees. To illustrate:
From left to right, (1) a bullet right out of the box, (2) a bullet that has been polished to match the copper pen parts below, (3) an uncoated bullet that was baked at 350 for 8 minutes, (4) an uncoated bullet that was baked at 350 for 10 minutes, and (5) a clear-coated (eastman high gloss clear) cartridge that was cured for at 350 for 20 minutes after flow-out (also at 350).
#1 is not bright, but is copper color. #2 is bright copper color. #3 and #4 have taken a bronze tint - and unevenly so. #5 has a slightly more pronounced tint, but the coloration is even.
Given that the heat alone causes the color change, I'm skeptical that a different brand of powder would change things. I am, however, willing to be convinced if Columbia adds some sort of corrosion-inhibitor.
Now, I'm sure I could still sell a pen with a tinted bullet, but I'd like to be able to pair a powder-coated cartridge with a copper kit (and have them match). I'd hate to have to drop back to brass lacquer, which is far less durable than powder paint.
Comments? Suggestions?
Thanks again,
Eric