While cleaning up the deck gear for "Sooner" I noticed that almost all of it is bronze with a pealing coating of chrome. About half of the chrome comes off with brushing. Sure would like to go with the classic greenish brown....
jim
P.S.
I did the search thing and read up on sanding & polishing etc. - was hoping for a chemical - or a shop name to send them to. Called the only chromer I could find in TX and no joy.
Process for removing chrome from bronze?
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kabauze
- Rough Carpentry Apprentice
- Posts: 59
- Joined: Sun Jan 23, 2005 11:32 pm
- Boat Name: Nevermind
- Boat Type: Pearson Triton #450
- Location: Santa Barbara, CA
- Contact:
Re: Process for removing chrome from bronze?
I have taken several old chromed bronze parts to a local plating shop and they have removed the chrome quickly and cheaply in their acid baths. Price is typically $10-15 for a portlight or for a collection of smaller parts. This seems to be by far the easiest, cheapest, and safest way. Strangely enough, even though Santa Barbara is pretty much now completely converted to a town of wealthy retirees and wealthy tourist shoppers, there is still a plating shop in the heart of downtown, smack dab in the middle of the highest rent block. There must be one close to you...ask a lady of a certain age where she takes her brass lamps to be polished :)
For parts where the chrome is already failing, like you describe, I've had some luck soaking them in 5% acetic acid (a.k.a. vinegar) for a couple of weeks. The rest of the chrome comes right off under a brass brush. This method sometimes does not take off the chrome undercoat, which is commonly nickel for bronze parts.
If you are really determined to do it yourself, you can use the dilute muriatic acid (properly known as hydrochloric acid) sold at most hardware stores for concrete etching and the like. This approach has a number of big drawbacks, though. The acid itself is nasty stuff and if you store it incompletely sealed, the fumes will destroy things nearby. For example, stories are legion of muriatic acid fumes eating the chrome off a car bumper in the same garage in which the acid is stored. It also likes to destroy its container - I once had some muriatic eat through an enameled baking dish - but strong PE seems to be a safe container material. The final problem is that if you do use muriatic acid to remove chrome, you end up with the chrome in solution. I'm no chemist, but there is plenty of readily available information on the hazards of chromium and chromium compounds. To be general, it's very toxic stuff. That's one reason why chrome and plating shops are much rarer then in yesteryear, as dealing with all the toxic waste is difficult and expensive. If all else fails and you are forced to go this route, make sure you have access to a hazardous waste disposal site to get rid of the used acid. For example, my county runs such a site at which we may take up to 5 gallons per month of hazardous waste for free.
The hydrochloric/muriatic acid MSDS:
http://grover.mirc.gatech.edu/data/msds/50.html
Some info on chromium toxicity:
http://www.atsdr.cdc.gov/csem/chromium/ ... fects.html
Personally, I never use muriatic acid nor would I even consider it.
For parts where the chrome is already failing, like you describe, I've had some luck soaking them in 5% acetic acid (a.k.a. vinegar) for a couple of weeks. The rest of the chrome comes right off under a brass brush. This method sometimes does not take off the chrome undercoat, which is commonly nickel for bronze parts.
If you are really determined to do it yourself, you can use the dilute muriatic acid (properly known as hydrochloric acid) sold at most hardware stores for concrete etching and the like. This approach has a number of big drawbacks, though. The acid itself is nasty stuff and if you store it incompletely sealed, the fumes will destroy things nearby. For example, stories are legion of muriatic acid fumes eating the chrome off a car bumper in the same garage in which the acid is stored. It also likes to destroy its container - I once had some muriatic eat through an enameled baking dish - but strong PE seems to be a safe container material. The final problem is that if you do use muriatic acid to remove chrome, you end up with the chrome in solution. I'm no chemist, but there is plenty of readily available information on the hazards of chromium and chromium compounds. To be general, it's very toxic stuff. That's one reason why chrome and plating shops are much rarer then in yesteryear, as dealing with all the toxic waste is difficult and expensive. If all else fails and you are forced to go this route, make sure you have access to a hazardous waste disposal site to get rid of the used acid. For example, my county runs such a site at which we may take up to 5 gallons per month of hazardous waste for free.
The hydrochloric/muriatic acid MSDS:
http://grover.mirc.gatech.edu/data/msds/50.html
Some info on chromium toxicity:
http://www.atsdr.cdc.gov/csem/chromium/ ... fects.html
Personally, I never use muriatic acid nor would I even consider it.
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Tom Javor
- Master Varnisher
- Posts: 100
- Joined: Tue Sep 16, 2008 5:06 pm
- Boat Name: Pandalus
- Boat Type: 1964 Sailmaster 22D hull #3
- Location: Warwick,RI
Re: Process for removing chrome from bronze?
Ask either at a motorcycle or custom car shop to find out who does their chrome work. If someone can do the plating they should be able to do the stripping. There are several places here in RI but the shipping would probably be a deal breaker.
TJ