Restoring Bronze portlights

My bronze portlights are badly oxidized. I tried polishing with
“Brasso” as ABI recommended but can’t even begin to get through the
oxidation. I tried naval jel to at least get rid of the thick stuff
but to hardly any effect. I hate to use a wire wheel. I thought I
heard somewhere that a sandblasting with something as fine as baking
soda has worked (done professionally of course). I see those removers
advertized on TV where you can just dip the part in (Tarnex?). I’m
open to any suggestions. Thanks.

The patina coating which forms on bronze and copper surfaces serves as a
protective coating against further oxidation and salt formation. If you
must remove this coating, try ketchup or soaking the piece in a kool-aid
type beverage. Both of these products contain citric acid which will
remove the patina coating without etching the surface of the bronze.


Have you tried this and do you see any problems with a citric acid
based paint remover I see in the marine stores? By the way, did you
buy your boat from Peter and Diane Laing in Maine. I have their
previous boat “Grey Mist”.

The “ketchup polish” was reported in a Boat U.S. Seaworthy report and was
extensively discussed at the Flicka Discussion Forum ) -see Flicka Notes - as well as proven to
work. I am not familiar with the citric acid type paint removers, hence can
not render an opinion as a chemist.

In answer to your last question about “IDUNA,” yes, Pete and Diane owned the
boat previous to us. They told us about “Grey Mist” and I believe my lovely
shipmate contacted you earlier.

As to polishing the bronze ports, I would recommend you leave the patina
protective coating on them. You will spend hours attempting to polish the
bronze and I suspect have very little success. The reason bronze is used in
a marine environment is because it is more electro-chemically noble than
stainless steel and forms a “self-healing” protective coating. Granted
polished bronze looks lovely but polishing exterior bronze defeats one of
the reasons for using bronze in the first place.


From Bristol Bronze,

You can use ScotchBrite hand pads. It will take a lot of rubbing but
they will cut through the oxide.
If you want to go through the trouble of removing the portlights then
the best thing to use is a ScotchBrite wheel on a bench grinder or
portable drill. You will have to do some hunting to find an
industrial supply story that carries the wheels but they do a great
job. You will need to wear a face mask because of the dust created.
Not only will you remove the oxide but the ScotchBrite will polish
the metal at the same time. We use two different grades of
ScotchBrite wheels in the shop as the next to last step in polishing.
If you want a mirror finish you can then move on to a jeweler’s wheel
and rouge.

Roger W.
Bristol Bronze