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  1. #16
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    Quote Originally Posted by RayG View Post
    Hi BT,

    If you like, I can send over a sample of the universal black patina for you to try?

    Ray
    Thanks for the offer Ray but let me try the gun shop first. They may have the Birchwood stuff or suggest something else.

    Bob.

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  3. #17
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    Have you tried a sulphate of potash solution works very well on copper don't know if it will work on brass

  4. #18
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    Quote Originally Posted by China View Post
    Have you tried a sulphate of potash solution works very well on copper don't know if it will work on brass
    China,

    It appears that liver of sulphur is sulphate of potash though there are other suggestions on this site - http://www.finishing.com/128/71.shtml

    My daughter reckons LOS doesn't work well on brass. She is going to have a look at a book in the RMIT library called " The Colouring, Bronzing and Patination of Metals" for a black recipe
    -http://www.amazon.com/The-Colouring-Bronzing-Patination-Metals/dp/0823007626 . My fear is that unobtainable chemicals will be involved if one is found. The gun shop or Ray's offer I think will be the easiest solution.

    Bob.

  5. #19
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    I've used Copper Carbonate in Ammonia Solution with good results and long lasting finish. To get Copper Carbonate, use Copper Sulphate reacted with Sodium Bi-Carbonate in distilled/deionised water. You get a precipitate of CuCO3 which settles rapidly. Decant the liquid and wash with precipitate with more deionised water to dissolve the remaining (soluble) component (this can be skipped). The CuCO3 will be malachite green in colour (verdigris) mix this with Ammonia (Household) try to avoid Cloudy Ammonia as it has a soap component which we don't want. Supermarkets used to sell household ammonia less the soap but you need to look around for it. The solution is a spectacular blue colour. You immerse your cleaned/degreased brass and copper items in this and the blacking becomes apparent. The longer you leave it the blacker it becomes.

    Reagents:
    Copper Sulphate (Bluestone) can be had very cheaply from Bunnings or any good garden centre (used for tomato fungus prevention) .
    Sodium Bi-Carbonate in the kitchen cupboard or supermarket.
    Ammonium Hydroxide aka House Hold Ammonia / Cloudy Ammonia Supermarket again or industrial cleaning suppliers.

    Copper Carbonate can be found at chem supplies or Pottery Suppliers as glaze. Reagent grade stuff will probably work better

    You can also make ammonium hydroxide but then we're getting into chemical factory territory.

  6. #20
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    Two stop shopping at Wesfarmers sounds good Swarf.

    You have made the recipe sound pretty simple. Thank you.

    Bob.

  7. #21
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    OK. I went to Bunnings and purchased some copper sulphate and cloudy ammonia. Came home and searched in vain for an over the counter supplier of ammonia. So I called into the local gunshop and picked up a small bottle of Brass Black for a cheap $15. I asked the bloke in the shop if it worked well on brass. He said he had never used it and hadn't heard from anyone else regarding its effectiveness.

    So here are the results. The instructions suggest swabbing the solution onto degreased brass ( I used metho as a degreaser as suggested at the shop.I was told it's what the gunsmiths use when using Super Blue on steel.). Swabbing resulted in an uneven, mottled finish. Too much swabbing and the finish came off. I ended up opting for total immersion for about 30 seconds followed by a rinse in clean water.

    The finish is even but not black, more a charcoal grey. It will do for the time being. If I can obtain some ammonia I'll have another go.

    BT
    Attached Images Attached Images

  8. #22
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    Bob,
    Try the cloudy ammonia but pour it into a jar and let settle , then decant off the top liquid. The soap seems to settle to the bottom. I've had good result with cloudy by doing this. Your blue solution from the gun shop looks awfully similar to the mix I've described. What does it smell like?

    Peter.


    Quote Originally Posted by Anorak Bob View Post
    OK. I went to Bunnings and purchased some copper sulphate and cloudy ammonia. Came home and searched in vain for an over the counter supplier of ammonia. So I called into the local gunshop and picked up a small bottle of Brass Black for a cheap $15. I asked the bloke in the shop if it worked well on brass. He said he had never used it and hadn't heard from anyone else regarding its effectiveness.

    So here are the results. The instructions suggest swabbing the solution onto degreased brass ( I used metho as a degreaser as suggested at the shop.I was told it's what the gunsmiths use when using Super Blue on steel.). Swabbing resulted in an uneven, mottled finish. Too much swabbing and the finish came off. I ended up opting for total immersion for about 30 seconds followed by a rinse in clean water.

    The finish is even but not black, more a charcoal grey. It will do for the time being. If I can obtain some ammonia I'll have another go.

    BT

  9. #23
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    Quote Originally Posted by Swarfmaker1 View Post
    Bob,
    Try the cloudy ammonia but pour it into a jar and let settle , then decant off the top liquid. The soap seems to settle to the bottom. I've had good result with cloudy by doing this. Your blue solution from the gun shop looks awfully similar to the mix I've described. What does it smell like?

    Peter.
    The Brass Black is close to odourless Peter. The Super Blue on the other hand took my breath away a bit like the old smelling salts, sal volatile.

    On the bottle of Brass Black, the directions suggest reapplication of the solution would darken the finish. It didn't. With your recipe can black be achieved?

    ( I had mentioned earlier that my daughter was going to have a look for some recipes. She sent me this, we both agreed we won't go there... Lead Acetate! )

    Bob

    image (Large).jpg

  10. #24
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    The super blue would more than likely to be same as my recipe if it's smells like sal volatile. The copper carbonate is soluble in Ammonia solution and turns blue. It does go very dark but how black is black? I blacked some very clean KS brass tube with it and it appeared blacker then grey but it did have a grey look about it under bright light but it was black enough for me.



    Quote Originally Posted by Anorak Bob View Post
    The Brass Black is close to odourless Peter. The Super Blue on the other hand took my breath away a bit like the old smelling salts, sal volatile.

    On the bottle of Brass Black, the directions suggest reapplication of the solution would darken the finish. It didn't. With your recipe can black be achieved?

    ( I had mentioned earlier that my daughter was going to have a look for some recipes. She sent me this, we both agreed we won't go there... Lead Acetate! )

    Bob

    image (Large).jpg

  11. #25
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    When I was looking for steel blackeners I trawled through dozens of MSDS, they tell you pretty much exactly what's in the different concoctions. In many cases they were very similar. There's an MSDS for Brass Black here https://www.birchwoodcasey.com/getat...-2012.pdf.aspx

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