Chromeing plastic parts

I was just thinking.
There must be some way to chemically chrome plastic parts.
Does any body know or have an idea?
Or does any body know if the major injection moulders galvanize their
"chromed" parts

Home telescope makes once used a chemical method to deposit silver on their hand ground mirrors. Unfortuantely, it was a risky and toxic procedure. And silver tarnishes. I'm sure you can find the recipe in old telescope making books.

Model parts are chromed by vacuum deposition. Parts are stuck in a vacuum chamber and chromium is vaporized inside. The vapor "condenses" and plates out on everything it touches.

Look in the phone book for chroming services. You should find them.
The car and motorcycle restorers use them all the time. I know one guy who plated a plastic model this way. It wasn't cheap, but it came out pretty cool! The look isn't what you'd want for anything other than a pampered, hand polished aircraft - like a race plane.

"Galvanizing" is a zinc dip process to prevent corrosion. Not what you want at all.

I got the impression that it's not that different from normal electroplating of metal parts; the trick is to make a conductive plastic (so you can run a current through it) that's thermally stable (so the chrome doesn't peel off in service).

That just leads to the question: "how do they get the copper on??"

You are correct.

Most plastic kit manufacturers use the Vacuum Metalizing like it is described in the thread about Christmas ornaments. And yes, the "chrome" is really Aluminum deposited over a shiny lacquered surface. It does look very close to real chrome.

The other method (also described in this thread) used by many off-shore model makers and it is real Chromium.

I'm not familliar with the process but I would assume that there is a layer of conductive laquer applied to plastic, then a layer of copper is deposited (same as when the real car parts get plated). Then a layer of
Chromium is applied. This is done via electroplating.

Neither of the methods is really suitable for a do-it-at-home hobbyist.
Electroplating is messy and uses some nasty chemicals.

Vacuum Metalizing requires special equipment (I'm sure it is expensive).

But I know of 3 places which will Vacuum Metalize parts for you.

ChromeTech USA (still in business)
Little Motor Car Company in USA (not sure if they ars still around).
The 3rd place was in Canada (and I don't recall the name).
All American Resin was using them for their plating.

As for electroplating, check your Phone Book under PLATING and make some calls.
You might get lucky, but the minimum price might be quite high.

There is another alternative. Use Alclad II Chrome paint.
It is for airbrush only, but if you follow their instructions you'll end up with a very nice looking chrome like finish. Not exactly like the other methods, but pretty close. And you can do it at home.

I don't have any URLs handy but I'm sure you can find all you need using a
Google search.

I won a ChromeTech USA gift certificate that's worth $20 and expires Sept. 04.
I will most likely never use it.
Rob Gronovius
Visit my motor pool in the www.armorama.com gallery