Powder coating over chrome plating

A. Hi Brian. No, it's not practical to get good adhesion to chrome plating because few things will stick well to chrome. But a powder coating shop can probably chemically strip the chrome. Or, at a Powder Coating seminar at the Southern Metal Finishing conference, a couple of shops reported successfully powder coating parts after a very light "sweeping" sandblast. This presumably removes the chrome (which is only a few millionths of an inch thick) and exposes and etches the nickel. This probably is a practical way to maintain the shiny chrome look under translucent powder coats. Still, it would be better to swap your chrome wheels with someone else's powder coated wheels if such a swap could be arranged :-)

A. You can do the powder coating first, Roger. I've seen much less expensive components than yours mass produced by powder coating the desired areas and then chroming the whole thing; no chrome will "take" on the powder coated area. I think it's a more reliable sequence. Good luck.

A. The only way that you are going to get a Powder Coating finish to go over chrome is to remove it, either with an acid or by shot blasting it off.

A. The few powder coaters I have dealt with find a good non-peeling chrome finish to be excellent for powder coating over. I don't know how many different processes there are for applying powder coating. So it may not work in all forms of application.
All of this doesn't mean much now since you will have to remove the current powder coat. Sometimes in the process of removing the powder coat the chrome undercoat will most likely get damaged. In that event the part will have to be stripped to the base metal.
Your best bet is to take it to a reputable chrome plater and have the plating stripped to the base metal.

A. It is not a good idea to powdercoat over chrome if the intent is to use the Motorcycles. If the motorcycles are purely for display it would be OK.
The problem is that there is nothing promoting adhesion and so the coating would be extremely susceptible to chipping.
Hope this helps.
Regards,
Bill

A. I have had excellent results with powder coating over chrome. Just make sure the chrome is not peeling or pitted and is thoroughly cleaned and free of all dirt and films before coating.

A. Hi Charles; we're all prejudiced and creatures of habit :-)

Although Frank Deguire has told us twice now that powder coating will stick to clean chrome fine, I've also listened to powder coaters describe how they must sweep blast components to remove the chrome and slightly etch the nickel for good powder coating adhesion.

But we all believe most confidently in what we've seen with our own eyes, and yes I've seen your approach of doing the powder coating first. I've watched tens of thousands of selectively powder coated parts go through the whole chrome plating sequence including cyanide copper strike, with the powder coating acting as a maskant, without a problem -- so that's an approach I personally believe in :-)

Regards,

A. Hi Bill. It was a thermoset powder coating of conventional thickness not exceeding a few mils, not a heavy thermoplastic coating. And it was for outdoor use, so it probably wasn't epoxy (but might have been a hybrid epoxy-polyester). But I can't explain the details any further -- both because I was involved in the subsequent plating operation rather than the powder coating operation, and because the company that was doing it is still in business and presumably would want to retain the benefits of any development efforts they may have put in. Although there were occasional problems at sharp edges and corners if the powder was allowed to get too thin because plating "trees" would grow through the pinholes (uninsulated corners draw high plating current), all in all it worked fine.

I perhaps left the impression that no development work at all is required and Charles can simply take his powder coated parts as they are and run them through through the chrome plating sequence -- but that may not be true. Whether his parts will work right out of the gate, vs. whether there might be development work required, I don't know.

Regards,

A. Hi James. I wouldn't chance it; I'd go with liquid paint. Although the chrome per se can withstand 400 °F, blistering of the chrome on alloy wheels is a very common problem even without heating ... and the tendency will be greatly increased if you bake them. Plating on aluminum requires a zincate immersion plating layer (with less adhesion than most electroplating), and alloy wheels are made of a rather trashy grade of aluminum for finishing. I'm not saying for sure that baking them would ruin them, but I think there is a good chance, not just a remote chance.

Regards,

A. Hi Daryl. You have to find a shop which offers to do this, but technically it's not a challenge. Powder coating makes a nice maskant for the chrome plating process.

Regards,

A. Hi Rafal. You can see lots of contrasting opinion on this thread, but my own limited book knowledge is limited to hearing about why powder coating on chrome is unsuccessful, so I can't suggest how to fix the issues except by removing the chrome first :-(

Have you done any tape tests or other tests which would indicate that functionally the adhesion is adequate and these fisheyes/pinholes/craters are your only problem? I think we'd like to see a photo with a tape measure included in it so we have a sure sense of scale before we ascribe a name to the defect :-)

Regards,