dirkclod
Well-known member
3 t01 or 2/1 ? Have been reading a lot here and am getting different mix's.Am doing fingers.
AP/Confused
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dirkclod
Well-known member
yea I have been trying a little of all and am now working 2 lbs at 3/1 and it just is a little slow. gonna make me a bucket setup with air and try 5 lbs next. I read somewhere on here they said they used 1 gal acid and 2 bottles of peroxide and I have not done the math [like I know how too] but guess maybe some one will shoot me straight !
You will probably find the ratios vary depending on where you look.
I do not go by ratios of HCl and peroxide, but if I did I would use the 2parts HCl to one part 3% H2O2 to get the process started, the whole point is to make a solution of CuCl2.
Once made it is the CuCl2 that dissolves copper, and you will be adding HCl and the oxidizer (Air or 3% H2O2) in increments as the solution becomes more saturated with CuCl from dissolving the copper into solution
Basically what you are doing is making copper II chloride, oxidizing copper into solution, once you have a solution of CuCl2 you will be adding HCl and an oxidizer air bubbling best (or small additions of 3% H2O2 to keep oxygen in solution).
The ratios as far as I am concerned are not that important, once you have a solution of CuCl2 it will dissolve copper from there you will keep solution working with additions of HCl and the oxidizer. The important thing is not to add too much oxidizer that will dissolve the gold, the 3% H2O2 is mostly water (97%) but even with this you can add too much, but as long as you do not over do it, the weak hydrogen peroxide is not too much of a problem, as long as you are dissolving copper and if you by mistake put gold in solution, it will cement back out as more copper dissolves into solution, but to keep the fine gold from dissolving in the first place it is still best not to over use the peroxide, bubbling air instead of adding hydrogen peroxide help to keep from dissolving gold, and it also helps to keep solutions from growing too fast in volume (from adding all of that water involved in the 3% hydrogen peroxide), all in all bubbling in air, although a bit slower to react at first, is best in the long run.
Read the documents on Laser Steve's web site, GSP just posted a good document on this etching solution in another thread on the same subject.
From one of the documents I have read it stated you can dissolve a pound of copper with 0.32 gallons of HCl and 1.87 gallons of H2O2.
With this in mind you can do the same thing with the HCl a tiny portion of H2O2 (to get the reaction started by forming CuCl2) and bubbling in air for the most of the process (to keep solution volume down to a minimum).
Some water is needed in the process to help to keep keep the copper salts in solution, but 32% HCl has a good portion of water, (the 32% acid is 68% H2O) so even if you just mainly used air as an oxidizer, the HCl provides water (water involved in the acid to begin with), and the also hydrogen from the acid, and the oxygen from the air you are bubbling into solution also form water in the reaction. so all of that water from the 3% H2O2 is not needed that much...
Keep in mind the leach is slow. And the thicker the copper it is expected to leach the slower it will be, temperature also plays a major role, but as with many solutions the higher the temperature the less gas or dissolved oxygen, it can hold so although warm can speed things up, Hot can deplete the needed oxidizers.
Cold can take a long time but also helps to keep oxygen in solution easier...
I do not go by ratios of HCl and peroxide, but if I did I would use the 2parts HCl to one part 3% H2O2 to get the process started, the whole point is to make a solution of CuCl2.
Once made it is the CuCl2 that dissolves copper, and you will be adding HCl and the oxidizer (Air or 3% H2O2) in increments as the solution becomes more saturated with CuCl from dissolving the copper into solution
Basically what you are doing is making copper II chloride, oxidizing copper into solution, once you have a solution of CuCl2 you will be adding HCl and an oxidizer air bubbling best (or small additions of 3% H2O2 to keep oxygen in solution).
The ratios as far as I am concerned are not that important, once you have a solution of CuCl2 it will dissolve copper from there you will keep solution working with additions of HCl and the oxidizer. The important thing is not to add too much oxidizer that will dissolve the gold, the 3% H2O2 is mostly water (97%) but even with this you can add too much, but as long as you do not over do it, the weak hydrogen peroxide is not too much of a problem, as long as you are dissolving copper and if you by mistake put gold in solution, it will cement back out as more copper dissolves into solution, but to keep the fine gold from dissolving in the first place it is still best not to over use the peroxide, bubbling air instead of adding hydrogen peroxide help to keep from dissolving gold, and it also helps to keep solutions from growing too fast in volume (from adding all of that water involved in the 3% hydrogen peroxide), all in all bubbling in air, although a bit slower to react at first, is best in the long run.
Read the documents on Laser Steve's web site, GSP just posted a good document on this etching solution in another thread on the same subject.
From one of the documents I have read it stated you can dissolve a pound of copper with 0.32 gallons of HCl and 1.87 gallons of H2O2.
With this in mind you can do the same thing with the HCl a tiny portion of H2O2 (to get the reaction started by forming CuCl2) and bubbling in air for the most of the process (to keep solution volume down to a minimum).
Some water is needed in the process to help to keep keep the copper salts in solution, but 32% HCl has a good portion of water, (the 32% acid is 68% H2O) so even if you just mainly used air as an oxidizer, the HCl provides water (water involved in the acid to begin with), and the also hydrogen from the acid, and the oxygen from the air you are bubbling into solution also form water in the reaction. so all of that water from the 3% H2O2 is not needed that much...
Keep in mind the leach is slow. And the thicker the copper it is expected to leach the slower it will be, temperature also plays a major role, but as with many solutions the higher the temperature the less gas or dissolved oxygen, it can hold so although warm can speed things up, Hot can deplete the needed oxidizers.
Cold can take a long time but also helps to keep oxygen in solution easier...
dirkclod
Well-known member
Thank You !! Am working on new bucket now and have a bubbler and hose coming, I will go to Laser S site and read ! Thanks again.
Hi !
AP is made with hydrochloric acid and hydrogen peroxide. Actually, your goal is to make a solution of copper chloride. This is what will disolve the copper to free the gold from fingers. If you were to put material in just hydrochloric acid it would not attack the copper, but it will attack copper oxide! In the begining you add just a little hydrogen peroxide to oxydize some of the copper and get the reaction going. as the copper chloride starts to build up in your solution it does the leaching and there is no further need for peroxide. a plastic tube from a fishtank air pump bubbling thru your solution will supply all the oxygen it needs
You can start a new AP batch with just a half cup of peroxide. It will be slow at first, the more you use it the faster it works.
Using too much can cause some of the gold to go into solution.
If you go to Lasersteve's website, he has a very good document that teaches how copper chloride works.
Hope this helps
artart47
AP is made with hydrochloric acid and hydrogen peroxide. Actually, your goal is to make a solution of copper chloride. This is what will disolve the copper to free the gold from fingers. If you were to put material in just hydrochloric acid it would not attack the copper, but it will attack copper oxide! In the begining you add just a little hydrogen peroxide to oxydize some of the copper and get the reaction going. as the copper chloride starts to build up in your solution it does the leaching and there is no further need for peroxide. a plastic tube from a fishtank air pump bubbling thru your solution will supply all the oxygen it needs
You can start a new AP batch with just a half cup of peroxide. It will be slow at first, the more you use it the faster it works.
Using too much can cause some of the gold to go into solution.
If you go to Lasersteve's website, he has a very good document that teaches how copper chloride works.
Hope this helps
artart47
