Summary for clear chromate over powder coat Discussion
clear chromate conversion over powder coat is the core question here: a customer wants an aluminum part powder coated, with a masked area later etched and given clear chromate. Paul Stepanek asks whether this is possible and whether the powder coat will be affected. The reply says the answer depends on the exact chemistry, and that more details are needed before judging compatibility. Specifically, the responder asks what the etch is, including its chemical type, strength, pH, and temperature. They also note that the chromate matters: trivalent clear chromate is generally much less aggressive to existing finishes than hexavalent yellow chromate. The practical advice is to run test pieces, since the interaction with the powder coating is uncertain without those details.
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Powder coating as maskant for Class I EN plating
Q. Hi I was wondering if it would be possible to apply a class 1 nickel plating on a raw steel section of an otherwise powder coated component without any additional masking?
Noah Rehman
– Toronto Ontario
August 12, 2025
“Electroless Nickel Plating: Fundamentals to Applications”
by Fabienne Delaunois et al
on Amazon
or
or
(affil link)
A. Hi Noah.
I don’t know quite what “Class 1 EN Plating” is. Can you give us a spec number that covers it.
If it’s an electrolytic nickel I’m confident you can do a powder coating which can function as a resist.
However, if that “EN” is an acronym for electroless nickel ⇦ huh? , then I rather doubt it. Even highly specialized, formulated-for-the-purpose, maskants often have difficulty surviving hot electroless nickel.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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⇩ Similar, related, Q&As — oldest first ⇩
Q. We have a customer asking for an aluminum part to be powder coated with an area masked that is then to have etch and clear chromate after. Is this possible? Curious if the powder coat will be affected?
Paul Stepanek
– Clackamas, Oregon
May 30, 2024
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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 a 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
Need quick confidential answers? $25
Need project assistance? $100/hr.
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.
Rachel Mackintosh
Lab Rat / WWTF – Greenfield MA
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!
M Stammerjohann
– Horsens, Denmark