Hi. I am making an adjustable bridge for my third instrument (Roadkill 3). It has a brass base plate which is starting to look a bit art deco. Thing is, I would like it to look tarnished but in working it I have had to file and paper it and it is now bright and shiny. I read that vinegar works, but it didn't work for me. I tried heating with a blowtorch but that didn't achieve much either, and nor did lemon juice. Any suggestions how I can get it to oxidise quickly? Thanks in advance. John
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Check out my latest build I had a very shiney tin sink drainer. Used spray on olive oil and cooked on high for about an hour. the coating on the sink drianer was pretty thick so it looks more like shellac. But a very light coating aged the fittings really well.
I know not a genuine patina but chemical free and gives the look for cheap.
Old chemistry coming back...the suggestions for bleach (chlorine gas) and urine (ammonia) are not bad. Another one that's cheap and available is Coca-Cola (phosphoric acid). Try this: get two 1-liter bottles of Coke. Put your brass in the first one for a week. Remove, expose to air. Look for etching, discoloration (no, not itching and discoloration!). If no joy, on day 7, drink the other liter of Coke, starting at 7 AM so you don't stay up all night. At around 8 or 8:30 AM, put your (hopefully) phosphoric-acid-etched brass in Bottle 2. Release the pressure on your bladder by peeing into Bottle 2. Wait another 24 hours. Empty nasty-smelling container into your obnoxious neighbor's prize begonias, and blame it on the cat. Expose your brass plate to the air for 24 hours.
You should have developed a patina. Your neighbor certainly will have :-)
Interesting discussion going on. If I may suggest trying some of your commmonly found liguid drain cleaners. I know many of them have label warnings stating they are not to be used on different types of metals.
From personal experience I know how they will tarnish stainless stain when my daughter poured some down the kitchen sink to fix a grease clog. Cost me more than a few bucks and a weekend to replace it.
Thanks for the information. I threw all my darkroom chemicals away many years ago. Didn't think that I would be likely to use them again. Things like potassium ferricyanide are probably best disposed of and not left lying around the house.
Hi Michael.
Thanks for that. Hope to have it on in a day or two.
I think the green patina on copper & bronze is poisonous. It obviously occurs on copper flashing & gutters & statues, but they aren't normally handled.
This is probably no better, but if anyone has old photography chemicals from dormant darkrooms, selenium toner for b/w print paper will make copper a dull dark gray pretty quickly (minutes at most). I don't know it's health risk rating at that point. I batted that around with some people on a photo forum once & we couldn't be sure what compound was formed on the surface or if it was stable. Sulfides & selenides were suspected. Either one based on copper might be a crude semiconductor.
Some really interesting suggestions. So far the bleach and the salt + vinegar combination have left it largely untouched. I did get a little pink colour around the edges when combining the salt/vinegar with heat from a soldering torch but even then only slight. I have done a bit more digging elsewhere and it seems as though brass comes in many forms (alloy combinations I suppose) and with different properties. I don't know what it is so it's difficult to predict.
I found some other recommendations but they all involve chemicals that may be hard to get. I will ring the pharmacist tomorrow and see if it is possible to obtain any of them. Just in case anyone is interested here is the list.
1pt copper sulphate to 2 parts water
barium sulphide (hot)
Ammonium sulphide 1gm
Water 7oz
Potassium sulphide 1gm
Water 7oz
Copper nitrate 1gm
Ammonium Chloride 1gm
Calcium chloride 1gm
Water 20gm
Phosphoric acid (no quantities given)
I was no good at chemistry at school but some of this sounds as if it might be hazardous. My problem is also that I would prefer to get the bridge on pretty soon so I really need something that works in a few hours (at most) rather than a few days. If all else fails it will have to go on as is and acquire it's ageing in the natural way.
Again, thanks to all for the help. Out of interest here is a pic of the piece in question.
Silly, but i think Wiley had so ething there -- urine. No joke. I know folks soak dyed material inurine to set the colors and urine has urea, sodium, chlorine and potassium. I bet that would work tho it could stink.
Replies
On lamp parts, I have used the same formulas and solutions that stained glass artists use to age copper and copper foiled lamps.
On brass, though, you do have to heat it up.
Check out my latest build I had a very shiney tin sink drainer. Used spray on olive oil and cooked on high for about an hour. the coating on the sink drianer was pretty thick so it looks more like shellac. But a very light coating aged the fittings really well.
I know not a genuine patina but chemical free and gives the look for cheap.
Michael,
Old chemistry coming back...the suggestions for bleach (chlorine gas) and urine (ammonia) are not bad. Another one that's cheap and available is Coca-Cola (phosphoric acid). Try this: get two 1-liter bottles of Coke. Put your brass in the first one for a week. Remove, expose to air. Look for etching, discoloration (no, not itching and discoloration!). If no joy, on day 7, drink the other liter of Coke, starting at 7 AM so you don't stay up all night. At around 8 or 8:30 AM, put your (hopefully) phosphoric-acid-etched brass in Bottle 2. Release the pressure on your bladder by peeing into Bottle 2. Wait another 24 hours. Empty nasty-smelling container into your obnoxious neighbor's prize begonias, and blame it on the cat. Expose your brass plate to the air for 24 hours.
You should have developed a patina. Your neighbor certainly will have :-)
Interesting discussion going on. If I may suggest trying some of your commmonly found liguid drain cleaners. I know many of them have label warnings stating they are not to be used on different types of metals.
From personal experience I know how they will tarnish stainless stain when my daughter poured some down the kitchen sink to fix a grease clog. Cost me more than a few bucks and a weekend to replace it.
Hi Murray.
Thanks for the information. I threw all my darkroom chemicals away many years ago. Didn't think that I would be likely to use them again. Things like potassium ferricyanide are probably best disposed of and not left lying around the house.
Hi Michael.
Thanks for that. Hope to have it on in a day or two.
I think the green patina on copper & bronze is poisonous. It obviously occurs on copper flashing & gutters & statues, but they aren't normally handled.
This is probably no better, but if anyone has old photography chemicals from dormant darkrooms, selenium toner for b/w print paper will make copper a dull dark gray pretty quickly (minutes at most). I don't know it's health risk rating at that point. I batted that around with some people on a photo forum once & we couldn't be sure what compound was formed on the surface or if it was stable. Sulfides & selenides were suspected. Either one based on copper might be a crude semiconductor.
Wow. Thanks Wiley, Shawn, Wes and Jamo.
Some really interesting suggestions. So far the bleach and the salt + vinegar combination have left it largely untouched. I did get a little pink colour around the edges when combining the salt/vinegar with heat from a soldering torch but even then only slight. I have done a bit more digging elsewhere and it seems as though brass comes in many forms (alloy combinations I suppose) and with different properties. I don't know what it is so it's difficult to predict.
I found some other recommendations but they all involve chemicals that may be hard to get. I will ring the pharmacist tomorrow and see if it is possible to obtain any of them. Just in case anyone is interested here is the list.
1pt copper sulphate to 2 parts water
barium sulphide (hot)
Ammonium sulphide 1gm
Water 7oz
Potassium sulphide 1gm
Water 7oz
Copper nitrate 1gm
Ammonium Chloride 1gm
Calcium chloride 1gm
Water 20gm
Phosphoric acid (no quantities given)
I was no good at chemistry at school but some of this sounds as if it might be hazardous. My problem is also that I would prefer to get the bridge on pretty soon so I really need something that works in a few hours (at most) rather than a few days. If all else fails it will have to go on as is and acquire it's ageing in the natural way.
Again, thanks to all for the help. Out of interest here is a pic of the piece in question.
Hydrochloric acid perhaps?
I read in Wikipedia at everybody find that own stomach but it might be difficult use it in your problem, maybe you find that in pharmacy.
-WY
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