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Topic: hydrosulfuric acid  (Read 38342 times)

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Offline BluRay

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Re: hydrosulfuric acid
« Reply #45 on: October 04, 2009, 02:38:49 PM »
1. I advise you not to produce H2S with sodium sulphide + an acid: it's very easy to generate enough amount of H2S to kill you...
2. So you haven't heated the coin while the gas was on it; try to do it (it's just a try). Maybe it can work.

Offline jamesslack

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Re: hydrosulfuric acid
« Reply #46 on: October 04, 2009, 06:12:11 PM »
heating the coin up and putting the H2S gas on it did this.

Offline jamesslack

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Re: hydrosulfuric acid
« Reply #47 on: October 04, 2009, 07:12:15 PM »
also do you think different type sulfur will give different colors or is sulfur all the same. i know different salts give different colors. now is sodium sulfide a type of salt.

Offline Borek

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Re: hydrosulfuric acid
« Reply #48 on: October 05, 2009, 02:54:47 AM »
All sulfur is the same, but each salt is different. Yes, sodium sulfide is a salt.
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Offline BluRay

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Re: hydrosulfuric acid
« Reply #49 on: October 05, 2009, 07:33:34 AM »
heating the coin up and putting the H2S gas on it did this.

Terrible! However, it does produce sulfide in thin layers... :)
In the beautiful picture of the coin you posted on September 12, 2009, 05:49:08 AM, I noticed that the coin's parts in rilief are more coloured, as if they have been attacked chemically more; for me it's strange that a simple the simple action of a still gas could do it, without other expedient. Maybe they started from a not-perfectly polished coin and then rubbed, or prepared chemically with a solid body the more external part of it before the chemical attack, or the put the coin at a certain angle in a grazing flux of the gas? (I'm asking to all people here).

Offline jamesslack

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Re: hydrosulfuric acid
« Reply #50 on: October 05, 2009, 07:08:15 PM »
i have been trying some anodizing, and i have seen that some sodiums give a driffernt color then others. is there a chart that you can look at to see what sodium makes a certain color. i will try the H2S gas agin this weekend and try to control it. but that stuff does stink.

Offline Borek

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Re: hydrosulfuric acid
« Reply #51 on: October 06, 2009, 02:58:52 AM »
No idea what you mean by "different sodiums".
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Offline jamesslack

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Re: hydrosulfuric acid
« Reply #52 on: October 06, 2009, 06:50:40 AM »
type of salts.

Offline Borek

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Re: hydrosulfuric acid
« Reply #53 on: October 06, 2009, 07:40:23 AM »
So correctly these have to be named "different salts of sodium". Basically every atom of a given element is identical, regardess of what compound it is found in, but as it is surrounded by other atoms of other elements it may behave a little bit different. Still atom of sodium isolated from sodium glutamate is undistinguishable from atom of sodium isolated from sodium chloride.

Nitpickers will tell you that atoms of element can be different, as they can be different isotopes, but it has nothing to do with compounds in which they are found, so for now we will just ignore it.
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Offline jamesslack

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Re: hydrosulfuric acid
« Reply #54 on: October 06, 2009, 08:09:27 PM »
i might never be able to make coins toned like some of the pro's but i have come along way from all the help here thank you very much. heres one i did today its got all the colors init but it still dont look like the one i was trying to get. but im happy with this one. thank you all

Offline BluRay

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Re: hydrosulfuric acid
« Reply #55 on: October 07, 2009, 06:43:36 AM »
And how did you achieve it? It's rather nice. You could even cover part of the coin to colour it only partially.

Offline jamesslack

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Re: hydrosulfuric acid
« Reply #56 on: October 07, 2009, 06:37:42 PM »
useing low volts and sodium salts, but still buying other tpye of salts to try.

Offline jamesslack

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Re: hydrosulfuric acid
« Reply #57 on: October 08, 2009, 06:52:57 PM »
heres what i found out so i dont think i will be able to tone the way i want, read this.The real secret is to buy a diffusion furnace, or maybe two, both a Chemical Vapor Deposition and an Atmospheric. On the CVD furnace one can add a nice uniform layer of polysilicon or nitride to beautifully tone your silver coins. and since you can control, temp, time and pressure you can control your deposition rate and get any spectrum of coloring that is completely natural and undetectable... For those stubborn coppers, we turn to the atmospheric furnace, and grow a slight layer of a high quality oxide at a slow rate, cause one has to remember that a grown oxide consumers its underlying surface as well as growing upwards... Ok, enough of the revealing the biggest trade secrets, 

Offline jamesslack

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Re: hydrosulfuric acid
« Reply #58 on: October 08, 2009, 07:13:38 PM »
heres the rest she had to say,     an atmo furnace with Hydrogen or h2 has to be properly mixed with 02 which then results in h20, a wet form of oxide growth which would not look natural and is of a lower quality and grows relatively fast, a dry oxide with heat and o2 and an added solvent such as tca or dce to remove impurities is the way to go Daddy-o, also, an n2 enviroment prior to temp up and growth is critical so one can avoid low quality native oxides, the more sophisticated systems use a pump to pump down the mini enviroment freeing all the area of 02 and creat a rich n2 inert enviroment... But I think I've said too much already...


Offline renge ishyo

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Re: hydrosulfuric acid
« Reply #59 on: October 08, 2009, 07:32:29 PM »
I think for your simple setup your result came out just fine  :)

Yeah, to control the exact appearance would take heat and control over the chemical environment. I did not know until I went snooping around that apparently there is a big controversy over toning coins as the coins collectors market used to pay high prices for "naturally toned coins".

This whole thing sort of reminded me of when my dad wanted to imitate the look of ancient Greek artifacts by giving his art sculptures that "green glaze" from exposure to copper metals and whatnot. He even went as far as to bury his sculpture in the backyard for a month in a chemical solution. He got the color he wanted, but it gave a uniform green film over the entire sculpture that looked unnatural. To go beyond that and control when and where the green color appeared on the sculpture would have required a quite complicated setup similar to the one you have just described.

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