super chrome wrinkling

[jtagger19]

I have use super chrome in lots of parts with no problems what so ever
how ever I was doing some galvanized steel parts yesterday
and the super chrome came out perfect as always
but once I applied the clear the chrome wrinkled under the clear
if you touch it you won't feel anything at all but you can see it wrinkled under the chrome
has this happend tro anyone else?
I did it twice and same thing happend

[dagobert]

If I had to shoot a guess at it, I'd say that since galvinized metal is known to let off some rather nasty fumes when heated if used as lining for an oven, that this may well be a similiar reaction occuring underneath the chrome powder base and is being trapped inside by the clear, and therefore reacting to the aluminum in the chrome powder during the heat of curing. Try this (in a WELL-ventilated area) next time- before you PC the chrome, strip the galvanization from the metal first using a chemical wash (probably muratic acid and distilled water; someone better in chemistry reading this can chime in anytime and correct me, please). Then, after rinsing it, use the phosphate treatment to prep it, and THEN spray the chrome powder/clear powder as normal.

See if that helps, and let us know.

[Blademan]

I was told that that galvanized stuff will only release the poisn gass's off at extream temps like when using a torch...I'm not a welder so I dont know how true this is...as far as the wrinkling goes thats a new one for me havent had it happen befor.

[dagobert]

It wouldn't have to be released into a gas just to have a reaction with the aluminum in the powder, would it? Once the bonding agent in the powder got hot enough to cure, that may be hot enough to react with the galvinizing. Or maybe not. It was just a possiblity, and a suggestion of something else to try. I don't have a chemistry lab to test my hypothesis, so the only other way is to try it and see if it works or not.

[jtagger19]

luckly the guy changed the color and black worked fine.
still I would like to test out and see what was it.
it if happens again I'll take pictures.

[dagobert]

Hmm. That would tend to support my theory that it was reacting to the aluminum in the powder. Oh well, all's well that ends well. But it would be nice to know why it happened for future reference. If you experiment with it any further, please let us know what you find.

[jtagger19]

I have some scrap pieces of galvaniced steel I'm going to try and if it happens I'll take pictures

[bzer1]

I would hazard a guess and say that potentially you are dealing with the heat differential between the zinc coating and the aluminum in the powder. Once the aluminum is trapped under the clear it will expand and contract at a different rate than the substrate, which is expanding at a different rate than the zinc coating. Maybe after applying the clear, ramp up to something like 300 for a few mins, then up to cure temp for a full cure cycle then turn the oven off and allow it to cool slowly... Just a theory on my part but it would make for a good experiment.

[jtagger19]

try 3 parts
1 came out fine 2 of them got wrinkled
here is a picture . since i don't know how to post pictures ,if it doesn't work it's in the album