Blackening of copper and tin & methods for tin plating

[Svet]

Hi guys, I am trying to copper-plate my (in)famous revolver and then blacken the copper plating to make it look like it was blued. Don't ask me why, it's just an experiment.
I am using cold gun bluing for the job. It does blacken the copper plating but it leaves a very slight, still noticeable, green tint to the whole look. In other words, what appears to be black is actually very, very, VERY dark green. I guess it is because of the formation of CuO which is naturally green.
My question is: is there a solution or a method that can make the copper plating look like real gun bluing? I mean, is there a way to make it look dark blue, dark brown or black but not dark green?
Maybe some stuff that does not rely on the formation of CuO but actually applies a new bonding layer of some other oxides/carbides/nitrates/whatever?

My other question is about tin plating.
How is fine tin plating done? I need a DIY solution because the commercial products used in the USA are not popular here, in Europe and because purchasing them online would be very unreasonable minding all the costs involved (VAT, customs taxes & shipping).
So again, I am looking for custom ways to apply quality tin plating to steel and/or copper.

And my last question is about blackening of tin.
I am using that same gun bluing solution that blackens copper for the job. It works OK, but I can't use it for immersion of large parts since it comes in small tubes of 20 ml.
Its other problem is that it makes tin dark grey, not black (like I want it).
Is there a DIY way to blacken tin? I mean to make it really, really black?

I asked same questions on Caswell Plating's forum (http://forum.caswellplating.com) but got warned by the moderators because they prohibit the posting of DIY recipies ont heir forum. Hehe, makes sence - maybe this is killing their business or something... Anyway.

Thanks in advance for your expert answers!

 

[dfariswheel]

Do a search on the internet for "blackening copper" and you'll get a number of recipes.

One method used by artists to really blacken copper plates is "Liver of Sulfur".
I think it's sold by artist's supply houses.

This is a liquid that's applied with a rag or dauber to the copper, and it almost instantly turns the copper a dark bluish-black color.
Like most copper blackening methods, it's not extremely durable.

I "think" Liver of Sulfur was used to blacken brass used on military equipment at one time, and was done by boiling the brass in the Liver of Sulfur.

I "think" that tin is plated just like all other platings are applied, by using a electro-plating setup and using a tin anode as the metal source.

 

[Svet]

Thank you very much, dfariswheel.
Do you happen to know the ingredients of this "Liver of Sulphur" thing? This is great that it does not leave any green tint. Sounds really cool.

I know that a salt bath, a car battery and a tin anode COULD do the tin plating job, but my question was rather about the ingredients of the salt bath.
I guess that commercial tin electroplating baths like the one Caswell Plating is offering have some kind of a tin oxide/carbide/sulphate included in thier formula.
Just like copper plating baths have diluted copper supate.

 

[dfariswheel]

Liver of Sulfur is a mixture of potassium sulfides.

It's simply called "Liver of Sulfur" and that's the name it's sold under.
It can be used to blacken brass, copper, and silver.

 

[mrmeval]

From an MSDS
http://www.jtbaker.com/msds/englishhtml/p5359.htm
Potassium Trisulfide 25%
Potassium Thiosulfate Hydrated 75%

I just found it in a search, not bought anything from them.
http://www.cooltools.us/Liver-of-Sulphur-p/los.htm?gclid=CN3Swbmk0IkCFQOYWAodrSh4Yg

This has a method of application
http://www.finishing.com/2000-2199/2063.shtml

Try an immersion blackening liquid with copper panels: 1.6 - 1.9 g/L liver of sulfur or liquid polysulfide solution at around 25 C for 50 to 80 seconds. As long as you optimized the conditions to get the color you want, you can blacken your parts.

The old way of doing tin plate was 'tinning'
http://en.wikipedia.org/wiki/Tinning

 

[mc223]

Might want to check Caswell also.

http://www.caswellplating.com/index.html

 

[Svet]

Thanks a lot for your help, guys.

What about tin electroplating? How is it done? Do I need tin sulphate or is a tin anode, some water and some salt enough for the job?
Do I need to copper-plate the piece first?

Also, how is iron plating done? What do I need? And again, do i need to copper-plate the piece first?

Thanks!

 

[Plink]

You might want to invest in Caswell's manual. It is loaded with good information on plating and how to avoid problems with it. I bought it when I started doing plating and it's an invaluable resource. I don't do tin or iron or I'd offer to help.