Blackening tin

? Hi, Mike. I strongly doubt that you mean actual tin metal, i.e., the chemical element "tin". You probably are using "tin" as slang for steel sheet metal?

The reason it matters is that the element tin reacts very differently to chemicals than the element zinc -- so it is important to know whether this metal is tinplate (tin coated) or galvanized sheet metal (zinc coated). Can you confirm?

A. Hi again, Mike. There is a black patina made for zinc (probably most often used by stained glass crafters). I haven't used it, but my best guess is it should work on galvanized steel sheet metal. Good luck.

Regards,

Black for tin

A. Black for tin (maybe for tin plate too):

• bismuth nitrate.....5 gm
• nitric acid.........50 ccm
• tartaric acid [on eBay or Amazon].......80 gm
• water...............1 lit
• Hot immersion(70 °C)!

Black for tin II:

• iron chloride........200 gm
• water................1 lit
• Cold immersion!

A. If all else fails, there's always black paint, Sean :-)

Most good black coatings, like black zinc plating, black nickel plating, and black chrome plating will prove impractical for work that is already in place. You could apply a cold black oxide (gun bluing), but this requires that the steel be very very clean, and it offers no corrosion resistance--you would have to keep the steel oiled, which is probably impractical.

 Yes, Tammy, muriatic acid dissolves the zinc coating almost instantly, leaving you with bare, rusted steel

Regards,

A. Hi, Charisse. Lead-free pewter is basically tin -- usually 90 to 98 percent tin. As such, Goran Budija's suggestions are probably the answer. Good luck.

Regards,

A. Hi Steve. I suspect, but don't know for sure, that commercial patinating solutions for pewter will darken tin. Let us know whether it works.

Regards,

A. Hi Garet. Most paint cans are made of tin plated steel, not zinc plated steel, so chemistry designed to darken tin will probably be more satisfactory. copper sulphate [on eBay or Amazon]will have some effect, but proprietary products which also include selenious acid will probably work better.

Regards,

A. Hi Marty. Google links are telling me that the most common Persian tray material is glass, but I suspect that the tin-plated tray that you are inquiring about is made of brass. There are blackening treatments for tin/pewter (and different blackening treatments for brass if that's what you actually have).

Can you tell us what you know about the tray, and send a photo of it to mooney@finishing.com please? Where the black has worn off is it silver colored or gold colored or copper colored? Many/most patinas and blackening solutions are not like paint that you apply on top of a surface, but involve a chemical reaction between the blackening solution and the particular metal of the surface. It's easier to predict what will work if you know what metal the tray or the surface of the tray is.

Regards,