Clear chromate conversion over powder coat

A. Hi Paul. I am familiar with a facility which made logo nameplates of powder coating and chrome plating by doing the powder coating first and using it at the maskant for a full copper-nickel-chrome plating process. So it is certainly possible to apply powder coating which will survive etch and chromate conversion coating.

However, I suggest that you carefully review this with the customer to avoid possible miscommunication because it sounds far more reasonable to etch and chromate conversion coat the whole item, then mask the area where powder coating isn't wanted. "Etch and chromate" sounds like an excellent pretreatment before powder coating :-)

Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi Paul,

I know nothing about the chemical compatibilities of powdercoat, nor even if there are more or less resistant varieties.

That being said, 2 pieces of info will help folks answer...

What's the etch? Chemical, strength, pH if not obvious (ex. Hot caustic is pretty obvious haha), and temperature.

What's the chromate? The trivalent (icy clear) kind is much less aggressive towards existing finishes than the hex (yellow).

Good scenario to run some test pieces, regardless.

A. Possible? Yes.

With every powder coat? Probably not.

Powder Coats span over such a wide selection of capabilities, that it is not something you'll cover in an afternoon or ten. However, there is very smart people out there, who can help you. Either your powdercoat supplier or someone who's done similar.

In terms of similar, we've had a client who had powder coating done AFTER anodizing, where simple masking was keeping the powder coat from the spots that didn't need it. Since powdercoat needs a connection much like anodizing, if you have an inert material protecting the area, it'll be free of powdercoat, regardless of your order of operations.

Though I imagine you might run into issues with temperature and the clear chromate, if you do it before the powdercoat?

I always recommend Google as one of your most prominent tools in this modern world and from a quick search, it looks like an epoxy based powder coat could solve your problem, if your etch is made from Sodium Hydroxide. (Search Terms: pH Resistant Powdercoat)

Good luck!