Powder Coat Clear on Bronze ABI Portholes

Hi All, has anyone powder coated bronze metal ?

At one point I wanted to use clear powder coat (polyester) my bronze ABI portholes.

I was told that it wouldn’t be successful, because the baking temperature would discolor the bronze base metal.

Is there any truth in that ?

A friend want’s to powder coat a bronze binacle in, white color, will this work ?

Douglas, BCC 072 , Calliste

From Powder Coating Online:

"BRASS: A yellowish metal that is an alloy of copper and zinc. Melts at 900 +or- degrees C. Highly polished brass resembles gold, however, this material will tarnish rapidly when exposed to the environment. A clear coating applied over this polished surface will reduce this tarnishing effect to a degree. Problems are often encountered when powdercoating a clear finish over this material when the copper to zinc ratio is increased. The copper has a tendency to turn the bright polished gold look to a semi-dull reddish appearance when exposed to accelerated cure temperatures commonly used in the powdercoating process. To overcome this problem one must reduce the maximum temperature that the part is heated to. This will result in a longer cure time at a lower temperature. Proper cure of the finish material must be achieved or the coating will fail.

COPPER: A Reddish-brown malleable, ductile, metallic element that is an excellent conductor of electricity and heat. Symbol = Cu, atomic weight = 63.54, atomic number = 29. Melts at 1083 degrees C, or approx. 1980 degrees F."

Douglas Wrote:

Hi All, has anyone powder coated bronze metal ?

At one point I wanted to use clear powder coat
(polyester) my bronze ABI portholes.

The portlights on Itchen were beautifully polished and lacquered when she came to us and now after a bit over five years they have darkened a bit but are still in good condition – except for the inevitable few spots where the coating has been physically damaged by accidental impact, or around the fasteners, salt water drips, etc. I suppose the same would be true of powder coating, even if it was possible to apply it without darkening – not possible, as Rod points out. Anyway, it’s just a matter of more or less time before any coating over polished brass or bronze begins to fail. When I next get around to stripping and repolishing our portlights I will find a source for Incralac and use that, sprayed, NOT brushed. It works longer than any other lacquer I know. Lacking a source for Incralac I would probably try several coats of Krylon clear spray lacquer from a local hardware or art store; it is a reasonably stable acrylic copolymer (if memory serves). This for the interior surfaces only – for the exterior i would use wax and then allow it to patinate naturally. When I was a teenager I spent a lot of time polishing brass on other people’s yachts, but it’s hard to find teenagers willing to do that these days and anyway it seems like overkill.
As for making the friend’s binnacle shiny white – why not Awlgrip or Imron, professionally applied?


Granted polish brass and bronze looks great but we think the patina that forms on copper based alloys fits the traditional workboat lineage of the BCC. In addition, because IDUNA’s hardware, fittings, irons, etc. are bronze from cranse iron to bumpkin fittings, we would be polishing bronze “forever.”

Scott’s thoughts about polishing and clear coating bronze, are well founded in his previous life, as is his suggestion to Awlgrip the binacle. As with varnish, there is no magic formula other than work.

Fair Winds,


 Best solution is to sail only in the Great Lakes.  I polish my portholes once in the spring and they are still shiny in October.......Tom  BCC118