cooknet
starting to spend too much on rocks
Member since February 2009
Posts: 169
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Post by cooknet on Nov 12, 2010 6:16:47 GMT -5
I was reading the thread here regarding treating porous stones with sodium Silicate to strengthen them and fill in the cracks as opposed to using an epoxy solution to the problem. I was wondering if anyone here had any additional info regarding the use of sodium silicate ( waterglass ) for this purpose. There are basically 2 different types of treatments I've heard of using sodium silicate, the 1st being to simply soak the stones after cleaning with TSP and also to heat the stones afterwards to bake the sodium silicate into the porous material. The 2nd type, which makes more sense to me is to change the actual structure of the sodium silicate once it has been absorbed into the porous material to get the silicate to polymerize in a non-water-soluble form, thus permanently sealing all the pores and cracks. I've been experimenting with sodium silicate for awhile now, and what I am not quite grasping is "how" to get the sodium silicate to polymerize INSIDE the porous material, rather than have it start to polymerize in a stainless steel container by adding the citric acid or whatever your using to cause the change to happen "before" the stones actually even make contact with the solution. This is how all the instructions for this treatment read, they say to add the citric acid (or whatever) to the sodium silicate and THEN add the stones, but as soon as you do that, the polymerization process begins, and it hasn't even seeped into the pores of the stone yet! So how to get around this? Soak the stones in sodium silicate only and THEN add the minerals later? Also, your supposed to bake the finished product after treatment to "fix" it permanently, but what happens if you don't bake it after you soak it in the polymerized solution? In case you don't have the thread, it's located here: forum.rocktumblinghobby.com/index.cgi?board=tips&action=print&thread=15452Hope to hear from someone who has perfected this treatment for a "step by step" procedure! Thanks! Chris
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Post by jakesrocks on Nov 12, 2010 10:04:11 GMT -5
I'll be watching this one too Chris. I've heard of many ways Sodium Silicate was used for preserving and repairing things back in the 30's, but never for stabilizing lapidary material. I hope someone can give a good description of how this works. Where do you buy your SS, and is there a brand name for it ?
Don
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Post by Woodyrock on Nov 13, 2010 3:20:54 GMT -5
I have run several trials using sodium silicate/catalyst to stabilize agate, and jaspers. As you have discovered, the reaction is quick. To get a better penetration, soak your material in the sodium silicate then apply a topical treatment of your catalyst. Potassium silicate is much slower in reaction, so is actually a better material than sodium silicate. Before heating, dry the treated material slowly first to prevent bubbling.
Jake: Prior to diamond wheels, and wet sanding, it was common to fill cracks, and pits with sodium silicate. Woody
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Post by jakesrocks on Nov 13, 2010 9:37:07 GMT -5
Hey Woody, I mentioned on another thread that sodium silicate was used during the depression years to preserve eggs for storage. Egg shells have tiny pores in them, and by dipping the eggs in waterglass and drying them, it slowed down spoilage for several weeks or longer. It was also used during the model A / T Ford years to seal cracked engine blocks. There were many other uses, but I can't remember them. Don
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snuffy
Cave Dweller
Member since May 2009
Posts: 4,319
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Post by snuffy on Nov 13, 2010 9:45:46 GMT -5
Where is a good place to get this. I've checked around and no one seems to know what it is .Is there a common name for water glass?
snuffy
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Post by Donnie's Rocky Treasures on Nov 13, 2010 10:10:43 GMT -5
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Post by jakesrocks on Nov 13, 2010 10:20:54 GMT -5
Trust Lehman's to have sodium silicate still listed as an egg preservative. Don
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cooknet
starting to spend too much on rocks
Member since February 2009
Posts: 169
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Post by cooknet on Nov 14, 2010 3:55:04 GMT -5
I have run several trials using sodium silicate/catalyst to stabilize agate, and jaspers. As you have discovered, the reaction is quick. To get a better penetration, soak your material in the sodium silicate then apply a topical treatment of your catalyst. Potassium silicate is much slower in reaction, so is actually a better material than sodium silicate. Before heating, dry the treated material slowly first to prevent bubbling. Jake: Prior to diamond wheels, and wet sanding, it was common to fill cracks, and pits with sodium silicate. Woody Thanks for all the replies, I really appreciate it!! So regarding the "topical treatment of the catalyst", what exactly do you mean "topical" I've been experimenting with a few different techniques, some are conflicting, and it's getting a bit confusing! Are you saying to submerse the stones in sodium silicate in a stainless container with a lid and then heat the solution with the stones in it on a coffee warmer or something like that over night, then, the next day, take the stones out of the sodium silicate, and let them air dry, then place them in the oven or heating device (in my case a neat little convection oven that is about a large microwave size) over night on lowest setting, but when you place the stones that you've removed from the sodium silicate onto the cookie sheet or whatever steel container is going into the oven with them in it to put the catalyst on the stones? Just dump some over top of the stones as they are going into the oven to cook? One technique says to simply cook the stones on low in the oven at 230 degrees or so for a couple hours, then reduce the heat to around 150 for a further hour, then let set over night, and don't open the oven door till the next day, while another says to set the oven on lowest setting and let cook over night. Which is the best way to "cook" the stones? Also, the other variable is the initial soaking of the stones in the sodium silicate, some say to put on a coffee warmer over night, while others say cold is just fine, which is best? Additionally, MUST you first soak the porous stones in TSP over night before the whole process begins? What if you don't?? What kind of catalyst do you use, aspirin, boiled down mineral water, mineral mixtures, food grade citric acid? If there was just one simple procedure to follow that would be great, but the many different techniques become very confusing when your first trying to figure out what works best. It's obvious that the technique that simply says to soak in sodium silicate then cook in the oven is not a complete treatment, as there is no catalyst involved, but what catalyst to use?? I have potassium silicate as well as sodium silicate, and actually, I received 2 large containers full totally free, I emailed a chemical supply company online, asked them for samples, and the shipped them, voila!!
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cooknet
starting to spend too much on rocks
Member since February 2009
Posts: 169
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Post by cooknet on Nov 14, 2010 4:01:10 GMT -5
Oh, by the way, the sodium silicate and the potassium silicate (also called Kasil-1 by the company)that I have is a rather thick liquid, do I dilute it 1:1 with water as some say to do, or leave it thick?? Do I add dish soap to allow it to seep into small cracks better by lowering it's viscosity, or not add soap? So many questions, so little time...LOL Chris
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cooknet
starting to spend too much on rocks
Member since February 2009
Posts: 169
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Post by cooknet on Nov 14, 2010 16:13:20 GMT -5
Any ideas to my questions anyone?
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catskillrocks
fully equipped rock polisher
Member since July 2008
Posts: 1,270
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Post by catskillrocks on Nov 14, 2010 19:38:52 GMT -5
Chris, I've no ideas for you, but this is an interesting thread, thanks for asking the questions. Looking forward to these answers myself. Good Luck!
Don
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Post by jakesrocks on Nov 14, 2010 20:33:30 GMT -5
Chris, the way I read the instructions, you do add the dish soap, to lower the viscosity. Going to have to order a Lehman's catalog, so I can get some of that stuff. Don
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cooknet
starting to spend too much on rocks
Member since February 2009
Posts: 169
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Post by cooknet on Nov 15, 2010 2:37:17 GMT -5
Thanks for your reply Don and umm..Don, hehe. What I'm most interested is hearing from Woodyrock again, so that he can expand in more refined detail about his suggestion to add the catalyst as a topical solution. I am interested in the specific procedure for doing so, and also to combine bits and pieces from all the different procedures into one "known good" procedure that has been tried and proven effective. All of the experiments that I have tried thus far to treat porous material have "failed" in my opinion for one reason and one reason only, the waterglass did NOT penetrate the material into the pores, but rather created a layer of sodium silicate (or potassium silicate)on the surface, and when it is polished off, down to the surface of the gemstone material, the coating of sodium silicate is gone, and the pores that existed previously still exist, and were not filled with the silicate as was intended on happening via the treatment. Why not? That's my question! Could the reason simply be because I did not properly pre-treat the material by soaking in TSP over night? Or is this one of those situations where a vacuum system is required to really SUCK the silicate into the pores of the material, so that when the topical catalyst is applied, the silicate then polymerizes INSIDE the porous material, instead of just leaving a coating on top of it? It's obvious that this treatment works, I would just like to know EXACTLY how to get the silicate INSIDE the pores, and as a hard clear polishable material that will give an otherwise pitted surface of a porous stone a nice shiny gem like finish. Any firther suggestions Woodyrock?? Thanks! Chris
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Post by Woodyrock on Nov 15, 2010 2:40:28 GMT -5
Chris:
I catalyze with propylene carbonate. By topical, I mean applying a small amount by brushing over the still liquid silicate. When you do this, you must put a small amount in a separate container to prevent contamination.
If, you want to fill pits, and cracks with a black material, get a tube of fireplace cement. It is a mixture of sodium silicate, and lamp black. Let it dry over night then cook it. Woody
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cooknet
starting to spend too much on rocks
Member since February 2009
Posts: 169
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Post by cooknet on Nov 16, 2010 0:44:51 GMT -5
Hi Woody , thanks for those great suggestions! What exactly IS "lamp black" by the way?? I've heard of it, but with my memory issues, I can no longer seem to retrieve that file....lol. I cannot seem to locate the fireplace cement, I've looked at Canadian Tire, and a few local hardware shops, none of them seem to know what I'm talking about, typical. So where can you get propylene carbonate? What is it mostly used for, maybe there is another name for it such as a trade name or product name rather than just "propylene carbonate"?? Is it a locally available substance, or is it one of those funky mail order things. I know people are having trouble just getting the sodium silicate, and I was also myself, until I contacted a chemical supply company in Toronto and asked them for free samples of their chemicals, so they sent me the sodium silicate, and the potassium silicate as well, that was very nice of them I must say, they didn't even accept my offer to pay the shipping. I have some citric acid, and some ascorbic acid, as well as a special acid mix consisting of citric acid, malic acid, and tartaric acid, would you recommend any of these as a catalyst? One set of instructions for polymerizing the sodium silicate recommended citric acid mixed in boiled down mineral water, would you say that any of these things would work if the propylene carbonate is not available? I was also told that plain old aspirin would do the trick as well, what do you think, is that true? I haven't tried that one yet. At what stage do you brush on the catalyst? After the stones are removed from the sodium silicate that have been cooking in it over night at low heat, or do you let it dry first after removing it from the sodium silicate, or do you even have to "cook" the stones in the sodium silicate over night? Will simply soaking the stones i the sodium silicate over night at room temperature suffice, or must the solution with the stones soaking in it be heated? Also, when you say to "cook it", can you be more specific about "how" to cook it and for how long?? I'm sorry to bug you with SO many questions Woody, it's just that I've done SO much experimenting now, and have had some really weird results, and certainly not "stable" results, I would like to get a standardized procedure to adhere to so that I can further develop my treatment based on the "basic" treatment that works and is proven to work, if you know what I men! Thanks again for your info, I really appreciate the reply!! Chris
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Post by Hard Rock Cafe on Nov 16, 2010 15:21:48 GMT -5
Lamp black is a pigment often used in paints. I believe it is powdered carbon, but I may be wrong.
Chuck
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Post by Woodyrock on Nov 17, 2010 3:04:04 GMT -5
Chris:
In sol-gel chemistry, which is what we are doing when we catalyse a silicate with an acid, just about any acid will work, since the reaction is set off by changing the pH. I have had some stone soak up the silicate, whilst others did not. I have found the best heat treatment is to air dry at least over night, then heat at 100F or a wee bit more for several hours to drive off water, then gradually bring the temperature up to about 400 degrees F. The Zachery treatment for turquoise is a sol-gel process that can only be detected by the elevated levels of Potassium in the turquoise. This method had been used to stabilize turquoise for over thirty years, but the company will not patent the process in order to keep it secret. I believe they use both vacuum, and pressure in this process. Something I was going to try, but have not yet was to heat a bath of thinned silicate with the slabs, and then slowly cool the bath, and catalyse when cool. Woody
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cooknet
starting to spend too much on rocks
Member since February 2009
Posts: 169
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Post by cooknet on Nov 18, 2010 15:20:42 GMT -5
Thanks Woodyrock for that info, my question still stands however about how to get the sodium silicate INTO the stone, the soaking and cooking in the solution still does not seem to work on the many porous stones I've tested it on, it seems to just "polish" off after the treatment, not penetrating the stone. Do I need to set up some kind of a vacuum thing to suck it into the stone??
Also, my other main question is that the sodium or potassium silicates are thick liquids, about the thickness of dish soap, maybe a bit thinner, do you use it straight, or dilute it 1:1 with water like many treatments say to?
If it is thinner, it might penetrate the stone better, especially if the dish soap is added, but if it is thin, no thick coating will develop on the exterior of the stone, thus filling the pits and cracks in.
Do you suggest a 2 stage treatment where I use thinned solution to penetrate the stone, then cook on a straight thick solution later on and re-cook it with that on it, to seal the surface better for polishing?
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cooknet
starting to spend too much on rocks
Member since February 2009
Posts: 169
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Post by cooknet on Nov 18, 2010 15:22:49 GMT -5
Oh, also, when I use the catalyst to polymerize it, will simply brushing it on suffice to polymerize it deep down, or do I need to let it soak in the catalyst before cooking it?
Also, do I need to totally air dry the stone after the initial soaking in the sodium silicate BEFORE applying the catalyst, or should I apply it when the sodium silicate is still wet, once it comes out of the soaking bath of sodium silicate??
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Post by jakesrocks on Nov 18, 2010 16:00:51 GMT -5
If you have access to a vacuum pump, soaking the stone in a vacuum certainly wouldn't hurt. It would draw all air out of any voids, and allow the sealer to fill them. A place I worked at used to seal porous aluminum castings in a vacuum chamber, using a special epoxy. Don
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