Repair white spots on bronze and antique bronze

A. Hi Bob.

Yes, there probably is a lacquer, or epoxy or other clear coat over your antique brass. That is necessary because brass quickly tarnishes if it is not lacquered or clear coated; and if the brass is blackened or "antiqued", the antiquing would have little wear resistance and would keep changing.

Although the white spots could be calcium deposits (water hardness) above the clear coat, they are more likely a discoloration from water permeating under/through the clear coat. If you look close you might be able to tell.

My strategy would probably be to try to wipe them off with vinegar [in bulk on eBay or Amazon] (which is a mild acid that rapidly dissolves calcium deposits). If the spots don't come off with vinegar, they are under the clear coat, and you would need to strip and re-apply it; that is do-able by a determined home handyman, but involves noxious and messy chemicals, and has the potential of additional damage if splashed or dripped. Best of luck.

Regards,

A. Hi, folks. Most brass or copper polishes are fine for bronze. If they are not aggressive enough you can try a power buffer with the polish (try it first in an inconspicuous area). vinegar plus salt is mild on people but very aggressive on copper and copper alloys like bronze, so you could try that in an inconspicuous area too.

But if the items have a lacquer or clearcoat finish, you'll need to remove that first.

If it actually is lacquer, you can remove that with lacquer thinner [on eBay or Amazon] (remember they're flammable).

If the clearcoat won't come off with lacquer thinner [on eBay or Amazon], it's not lacquer, but something more robust. It can probably be removed with Aircraft Stripper, but only attempt it outside, from upwind, wearing goggles [on eBay or Amazon] and rubber gloves [on eBay or Amazon] because aircraft stripper contains truly noxious and toxic MEK. See letters 22020 and 21436 for additional ideas and detail. Good luck.

But a problem remains on all of the entries on this thread: one person's corrosion pitting is another person's calcium hardness, is another person's water rings, is another person's something else. Please send good in-focus photos of the discolorations to mooney@finishing.com for posting here. If that is impossible for some reason, try to be exceptionally clear with your description and wording so we can picture what you're talking about, rather than offering a cure to a different problem :-)

Regards,