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Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen

Posted by Andy  
Does anybody know how to clean acrylic off a specimen without damaging the specimen? I sprayed acrylic on the specimen to seal it but now I want to return the specimen to its natural state. The specimen is from the World Copper Mine in Nevada. Also, does anybody have a good way to clean off rock saw oil off a piece of rock? I have a piece or slice of jade that is discolored after it was cut with a rock saw, pretty sure the discoloration is from the oil soaking into the jade. The piece also feels oily when you touch it.
Thanks-
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 16, 2005 05:00PM
For the oil over the jade you can try the use of an organic solvent like petroleum spirit or something like it. I've never tried and I'm not sure that it can work well or damage the sample.I don't think, but it's better to try on a small part of the sample. For acrylic, I'm not sure but other organic solvent like methylene chloride can work well. Also in that case I suggest to test on a bad sample. I know that those solvent are quite uncommon...
Bye
Paolangelo
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 16, 2005 07:00PM
...remember also that those solvent are toxyc and you need an "expert" person and a laboratory to work with them!
Best regard
Paolangelo
I don't have a bad sample to test it on. Is there any acid that will take care of the job? Isn't Petroleum Spirits paint thinner? Maybe soaking the jade in mild dishwashing detergent/water solution for a couple days will take care of the oil. For the Azurite, is there any household item or something you can get at a hardware store to get off the acrylic or not make the acrylic coating as thick since I sprayed too much when I sprayed the acrylic? I don't have access to Methylene Chloride. The acrylic is on pretty heavy. Can acid eat away acrylic? Need something that will eat away at acrylic but not the specimen.
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 17, 2005 10:27AM
Acid can also remove all the carbonates like azurite and malachite;I suggest to not use it on that sample! You can try with other organic solvent used also for paint but I'm not sure that they can work well: acrylic is an organic compound, so you need a good organic solvent to remove it. Inorganic acid can damage the sample. If you have already some solvent for paint like ethyl acetate, methyl ethylketone or acetone you can test (using small amount of solvent). A good way can be:
_take a bad sample of some carbonate like calcite or dolomite and spray over it the acrylic
_then test over it the solvent you want to use (you can buy some different solvent from a paint factory or some hardware store)
_if you see some effervescence the solvent is too acid for your sample (ethyl acetate often has some trace of acetic acid inside). If you don't see any effervescense there are many chances that the treatment will be good also for azurite or malachite.
Petroleum spirit is a paint thinner used for some enamel!
For the jade: some dishwashing detergent are quite strong and I don't use it over my sample! If you want you can try with a skin soap with neutral pH (diluted). If you buy some solvent to try the removing of acrylic you can test also with jade (on a small part before).
Chemical reagents and solvent often have different specific due to the different use they have. Some stabiling agent, impurities and other compound inside make them different and it's better always test them over small part of the sample or over bad sample. It's also useful reading the label before use.
For methylene chloride: if you know some chemist, I am quite sure that he can provide you liters of methylene chloride.
Best regards
Paolangelo

P.S.I'm sorry for my english... I'm trying to improve it
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 17, 2005 10:30AM
Sorry: stabilizing agent...
For the jade, what about making a mixture of Dawn dishwashing soap and water? I am talking about the kind of soap that you wash dishes in the sink with, not the kind you put in the dishwasher. I have used a dawn-water mixture before with a piece of agate/quartz, I cut and I let it soak 2-3 days in it and it worked fine. I don't have a bad sample at all to test solvents on. Would nail polish remover do the trick for the acrylic? Nail Polish Remover is acetone I think. I also wrote in on the forum that is called "cleaning native copper" and I asked what is a good way to clean polished copper. And the piece of polished copper is not tarnishing green instead it is tarnishing a dark brown and the shine is going away. Have tried vinegar and scrubing with a toothbrush, which got rid of the tarnish (I guess that is what you call it) for a week, then it came back. Maybe because I rinsed the vinegar off with water.
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 17, 2005 06:29PM
For the jade you can try with the dishwashing soap:make sure that the solution you obtain in water is neutral (you can use the indicator paper that you can find in chemist's shop: you need pH not too acid and not too basic); jade is unsoluble in acid, but it's better to avoid strong tratment. If you have pH 5 or 9 and you treat it for some hours I think it will be not a problem. For the acrylic you can try the nail polish remover: it's a good idea I think.But probably it isn't acetone but methyl ethylketone (in recent time it has substituted acetone for that use!).If you don't have any carbonates to test try over a shell of an egg: it's made of carbonates too.The reaction is the same: if you see effervescence it means that the solvent you are using contains trace of acids and it's too strong for your sample.
Sorry, but I have not read the forum about the cleaning of native copper. Usually I don't remove secondary minerals from any sample. The brown tarnishing can be a mixture of sulfide and oxide and, maybe, a coating due to the pollution.
You can try with diluted ammonia. Also in this case I suggest to test the treatment on the bottom of the sample.
The copper cation can be complexed by ammonia turning the solution to blue: if you see that the solution you are using is turning to blue you are removing some copper ore. And probably the sample becomes shiny.
How diluted should I make the ammonia for the copper? The brown formed after I bought it, it was shiny when I bought it. I have nail polish remover that is acetone. Would that be better than the non-acetone? Should I soak the azurite in acetone? Is the dishwashing soap okay if it is like Ph 5 or 6 (slightly acidic)? For the jade, I also have concentrated degreaser which on the ingredients just say's greasecutting agents, sulfactimides (unsure of the spelling), akaline salts, and a couple other things.
Thanks-
....Maybe Ph 4 would be okay?
Thanks-
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 18, 2005 06:15PM
Acetone or methyl ethylketone are not too dissimilar one from the other regarding solvating properties. If one can function also the other can work well. They aren't ideal solvent for acrylic but working slowly I think that you can remove it. Before soaking the azurite in acetone, try to soak an eggshell:just to be sure that there aren't acidic traces. The problem of the jade: as I have already said,jade is unsoluble in acids, but it's better to avoid any strong treatment: the can damage the luster of your jade. If you have pH 4, I suggest to adjust it to 5 or 6 by adding some sodium bicarbonate (the same used for stomach)!
For the ammonia: read the concentration on the bottle you have; then say me the concentration. It's indicated in % (usually).
I don't know if you are familiar with concentrations. I will suggest you how to work. This evening or tomorrow I will test different concentration of ammonia over copper.
You are wellcome
Paolangelo
Andy Davenport
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 22, 2005 08:58PM
The ammonia does not say the concentration. Should I soak the azurite specimen in acetone or just wet it with acetone? Can you use a plastic container to soak it in. How long should I soak the jade in a ph 5 soap solution?
Thanks again-
avatar Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 23, 2005 04:31PM
How about nail-varnich remover, since most nail-varnishes are acrylic?
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 25, 2005 09:27AM
Usually the concentration of ammonia for domestic uses is less than 6%.So you can make a useful solution by adding 1 volume of ammonia to 2 volumes of water (usually is better adding ammonia to water... chemists say that it's better not to give drink to acids and basis!). You can use cotton to wash with ammonia your sample.
For the container: it depends from the plastic container you are using: remember that acetone can damage some plastics... if you have a glass container big enough I suggest to use that.
If the crystal of azurite you have are small, I suggest to soak for 2-3 minutes, let dry, look at the situation of acrylic and then, if necessary, repeat the operation increasing the time.
For jade: I suggest the same treatment but starting from 10 min.
avatar Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
December 27, 2005 02:58PM
de    
Lloyd,

Nail-varnish removers basically consist of nothing else than acetone.

Regards,
Peter
Cleaned the native copper using pure ammonia, cleaned it off good, but used it on a more polished piece, it didin't do much, and might have put a yellow/golden spot. I cleaned it before I read you message. Soaked the jade for 2 hours in a dawn/water solution, cleaned the oil off. But, the rough part turned light green with whitish spics. The dawn dried it out a lot. Hope I didin't damage it. That is what is causing that probably. The cut part looks perfectly fine. Havn't tried the acetone on the azurite yet.
-Andy
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
January 04, 2006 06:25PM
I have no idea about the yellow/golden spot on copper: have you tried washing it with water and driyng it immediatly with cotton or paper? For the jade:probably dawn has dried the jade, but there is also the possibility that you are looking a surface ruined during the cutting. The oil probably was hiding that part.
Paolangelo
What I was meaning about the jade, there is like a super light coating of white powder/spics (hard to explain) stuck to the rough part of the jade. Could this be water residue, minerals deposits from the water, or residue from the dawn? Might try the vinegar/flour mixture (maybe baking soda also) mixture for the one piece of copper. It worked before. But, it came back. How long would you think it would take the acetone to fully take the acrylic off? It is a pretty thick coating which is why I don't like it. Could it just take some of the coating off, so the coating is not as obvious, but it still stays sealed. I remembered now why I sprayed it, the crystals were brittle and rubbed off. But, I sprayed too much on which I tend to do. There are about 2 coatings of acrylic on it.
Re: Cleaning Acrylic off Azurite/Malachite/Chyscolla Specimen
January 07, 2006 06:15PM
For the jade: try to wash it with hot water (not too hot... 50°C): much of the residue of soap can be removed by this way,and also many deposit of mineral from the water! Are you sure that your copper is not an halloy? Obviously,natural copper samples contain other metal in traces (Ag,As,...)... I'm referring to halloy in wich other metals are present in amount similar to copper! Usually ammonia treatment is sufficient to remove most of the coatings from copper! You can try with very diluted acid not oxidant, but I have never tried and I can't guarantee the safety of your sample. Vinegar is an acid not too concentrated. After the washing with ammonia, which color was your ammonia?
I guess that the coating you are looking to is a sulfide. So,in that case, everything that remove the coating, can also damage your sample!
If you want you can repeat the treatment with vinegar but, in that case, after the treatment, wash with water and immediately with ammonia. Then conserve the sample in a closed box (a cabinet for example), to prevent the formation of new coatings.
For the acrylic: remember to test your acetone on an eggshell before (if you see any effervescence, don't try on your sample!).
Then soak your sample for 2, take the sample from the bath and let it dry. Look at you sample with a lens and check the situation. If acrylic is still present repeat the treatment but never for a long time (max 3-4 minutes). Every time you repeat the treatment check the integrity of your sample.
I do have a water softner on my water system. Don't know if that effects anything. What would the jade look like if it was damaged? I don't think the copper is an alloy as the coating wasn't there when I got it and was removed by the vinegar. The problem was I had to wash it off in water. And that maybe at fault for the coating coming back. After, I did it, I put it in a closed cantainer, not airtight, but closed and the coating came back. It is a yellow-gold-brown coating and is not shiny. Makes it look dull. The other piece the coating was almost black, but it came off with the ammonia pretty good, but not back to like it was when I got it, but improved it very well. The one piece I have where the coating came off is a smelted piece of copper (native copper melted down into a nugget shape, but not tumbled) and the other where the coating won't come off is a tumbled piece of native copper. The smelted piece has a rougher surface since it is not polished. But, this coating has not happined to my native copper specimens (rough, found out of the ground copper), just the smelted/polished pieces I have. My native copper pieces have stayed a beautiful shiny copper color with minimal green oxidation which was there when I bought it and has not oxidated any more.
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