Removing tarnish on brass, copper, bronze, p.2

Don't look at me like that, it's spooky! :-)

A. Hi Alex. Assuming it has no historical value, you can certainly try to restore it yourself. But what I'd try first is simply museum wax ... the waxing process should rub away the worst of the really loose corrosion products, and give a more consistent look to it while deterring future corrosion. If that doesn't make it "good enough" for you, you would need to re-apply a patina solution.

Regards,

A. Hi again. Unfortunately, I can't even guess what that corrosive substance is, or why it's oozing out. Hopefully another reader will have seen something similar.

Regards,

A. Castings can be very porous and any trapped chemical can leak out (amongst my foundry partners and platers (brass) we surprisingly call it "leakage") through any crevice it can find once you add the patina. With copper alloys you will get the verdigris (should look and feel like crystals). It is from not properly cleaning and drying out the metal before applying the patina. The acidic water mixture will ruin a piece. You would first have to make sure you dry the piece out, if it isn't already (some people bake the piece). You can then clean it, but it will be really difficult to match the patina - lucky it isn't gold or silver plated.

I have a ton of bronze here with verdigris and often have to use a blend of various paints to match it (cheaper then replating and okay on small spots), same goes with the various bronze colors. If the piece is not valued, I would strip it (media blast) and redo the patina so it matches. You can note the same issue near your water heater when the plumber gets lazy and doesn't clean the joints properly after soldering.

Hope this added something, other then stress.

Q. Thank you very much James Pessy! I think you are right in your diagnosis. The piece was sold to me as an antique, it probably is not.
But, it is really good looking and well done. I am planning to dry it in the oven at low temperature, lets say 300 °F, then clean and apply new patina.

It is not a solid piece. The walls feel thick, but it is hollow inside, like a ball. Is it OK to put it in the oven?

Thank you again!

A. Before having something professionally repatinated, Briwax for Bronze is a good alternative...

It cleans - but not too harshly - and won't do anything that can't be reversed.

Specifically, that very cool Chinese(?) bronze head - who knows how old it might be - really best not to do anything that can't be taken back!

I like it, anyway! :)

A. Veneta,
It's always difficult to tell for certain from a photograph, but to me it looks more like a coating that is failing and revealing the metal underneath.

A. Normally I suggest a mild acid such as citric for getting tarnish off of brass. With how that looks, it might need either a very long soak in a mild acid, or an acid that isn't quite so mild. Phosphoric has a little more kick to it while still not being overly dangerous to work with.

Ray:

Thanks a million. I'll try it.
Bob

A. Hi Josh,

Sounds to me like black copper oxide from excessive heating or burnt on carbon from a yellow flame from a fire or stove. Any chemical treatment is likely to need aggressive chemicals and not recommended for home use. Also there is no guarantee of success. I would try rubbing with a fine emery paper. Use the finest grit that will do the job. You will have to polish out the scratches left by the emery to get a uniform finish. Test the routine on an inconspicuous area first!

Harry

Thank you very much for your response. I will try this and let you know how I get on!

Cheers,

Josh

Harry - thank you very much for the advice.

I ordered some "micromesh" abrasive sheets and have done the job perfectly.

A bit of elbow work with this removed all the blemishes and the tarnish, but then a traditional polish has buffed it up to a remarkable finish, though how long for I don't know!

Thanks again Harry, very happy kettle here!

Good. Thanks for letting me know Josh.

Harry