zarguy
fully equipped rock polisher
Cedar City, Utah - rockhound heaven!
Member since December 2005
Posts: 1,791
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Post by zarguy on Nov 7, 2017 13:21:43 GMT -5
I was asked in a PM about Hxtal, a 2 part epoxy I use for stabilizing slabs & cabs so I decided to make the info available to everyone. In a Google search of Hxtal the first result is the manufacturer. They have a Distributor page listing various sites to buy it from. I buy from these guys: www.hisglassworks.com/shop/adhesives/epoxies/hxtal-nyl-1.htmlMake sure to get residual oil out of the material. Soaking slabs in Dawn dishwashing soap or your favorite solvent can help. Then I run the slabs through the dishwasher. It's OK, the amount of oil in a slab is minimal & won't adversely affect your dishwasher. I set my slabs/cabs on a piece of steel sheet or block. I heat them with a 100w incandescent light bulb as close as I can get it - 1-2" until it's too hot to touch (an hour or so). My bulb is in an articulated desk lamp which lets me position it close to the stone. The lamp has a metal shade which concentrates the heat. Mix Hxtal on a scrap of coated cardstock with a flat toothpick. Pointed toothpicks are not good at mixing. Uncoated cardboard may soak up some of the chemicals & alter the ratio of the mix. Mix thoroughly. Use the toothpick like a squeegee to make sure all gets mixed well. I've transferred the Hxtal into small squeeze bottles I bought at a craft store. Joann has a 6 pack for $3. (edit 04.09.2022 - not anymore) I mix small quantities, as in 2 drops of B & 6 drops of A, so there's no waste. It's expensive. Apply mixed Hxtal with same toothpick. Continue to heat for a least a couple of hours. I often forget about it & heat for 3-5 hours. Let cool. Wait a day before grinding or cutting. Maybe someday I'll add some photos of my setup & process. Gotta make Scott happy! Lynn Tommy
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Post by rockjunquie on Nov 7, 2017 16:49:55 GMT -5
Thank you. Yes, photos would be awesome. What is the viscosity of the mixed material like? Does it fill cracks readily? I assume it must or people wouldn't use it. I have not yet purchased any. The price scares me. Which leads me to the next question- what is the shelf life of it?
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gemfeller
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Member since June 2011
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Post by gemfeller on Nov 7, 2017 17:06:17 GMT -5
I can answer a couple of your questions rockjunquie, especially the one about shelf life. I bought some about 10 years ago and it sat on a shelf in my dimly-lighted shop because I just didn't get around to using it. It came in dark brown-colored bottles and endured some pretty extreme hot summer temperatures. I decided to try it on a slab of dinny bone with some open cells a couple of weeks ago. I used pretty much the procedure outlined above and it set up just like it should. So I think the shelf life's pretty good. I used a bit too much hardener because it set up pretty fast when heated after application. I think normal curing time with recommended mixing (3 to 1)is about a week and because it's so thin it should penetrate right through any cracks or openings in the slab. I think using less hardener than I did so it's more runny, and letting it cure slowly, will do a better job of filling all possible cracks and fissures.
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Post by rockjunquie on Nov 7, 2017 17:11:22 GMT -5
I can answer a couple of your questions rockjunquie , especially the one about shelf life. I bought some about 10 years ago and it sat on a shelf in my dimly-lighted shop because I just didn't get around to using it. It came in dark brown-colored bottles and endured some pretty extreme hot summer temperatures. I decided to try it on a slab of dinny bone with some open cells a couple of weeks ago. I used pretty much the procedure outlined above and it set up just like it should. So I think the shelf life's pretty good. I used a bit too much hardener because it set up pretty fast when heated after application. I think normal curing time with recommended mixing (3 to 1)is about a week and because it's so thin it should penetrate right through any cracks or openings in the slab. I think using less hardener than I did so it's more runny, and letting it cure slowly, will do a better job of filling all possible cracks and fissures. Great! Thanks!
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zarguy
fully equipped rock polisher
Cedar City, Utah - rockhound heaven!
Member since December 2005
Posts: 1,791
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Post by zarguy on Nov 7, 2017 17:23:11 GMT -5
rockjunquie , It's pretty thin. Thinner than most epoxies. In fact, I've had it flow through a crack to the other side of the slab & glue the slab to my metal block. Now after the initial heating, I sometimes put toothpicks under the slab to keep it off the metal. I got an inexpensive sample from helen, a member (former?) of this forum. After trying it out, I bought some & split it with a lapidary friend. I've since bought the 1/4 lb kit for myself. It seems that most of the best stuff I find needs to be stabilized. I recently had some beautiful Dino Bone that was so porous, that it just wouldn't take a shine. It soaked up the Hxtal & took an awesome shine. I thought I was going to keep it & wear it myself. While wearing at my most recent show, a woman asked if it was also fore sale. She owns it now! I haven't had any problem with the separate components hardening or yellowing. Lynn Sorry about the photo quality. I took it moments before she walked away with it.
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Post by rockjunquie on Nov 7, 2017 17:27:52 GMT -5
rockjunquie , It's pretty thin. Thinner than most epoxies. In fact, I've had it flow through a crack to the other side of the slab & glue the slab to my metal block. Now after the initial heating, I sometimes put toothpicks under the slab to keep it off the metal. I got an inexpensive sample from helen, a member (former?) of this forum. After trying it out, I bought some & split it with a lapidary friend. I've since bought the 1/4 lb kit for myself. It seems that most of the best stuff I find needs to be stabilized. I recently had some beautiful Dino Bone that was so porous, that it just wouldn't take a shine. It soaked up the Hxtal & took an awesome shine. I thought I was going to keep it & wear it myself. While wearing at my most recent show, a woman asked if it was also fore sale. She owns it now! I haven't had any problem with the separate components hardening or yellowing. Lynn Sorry about the photo quality. I took it moments before she walked away with it. Looks great, thanks. I guess I know what I need to get.
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Tommy
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Post by Tommy on Nov 7, 2017 19:44:00 GMT -5
Thanks for the post zarguy. Yeah I have to admit to getting sticker shock too with 8oz at $80 compared to 8oz of Opticon at $32. After I took a deeper look at it and having watched a few of the video on mixing it seems like you'd use less of the Hxtal - mixing precisely what you need to coat a given area. I don't stabilize very often but I'm always struck by the amount of opticon that gets wasted pouring it in and out of the container and wiping off the excess etc. Would you agree with this assessment Lynn?
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wampidytoo
has rocks in the head
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Post by wampidytoo on Nov 7, 2017 20:36:39 GMT -5
Thanks for the post zarguy. Yeah I have to admit to getting sticker shock too with 8oz at $80 compared to 8oz of Opticon at $32. After I took a deeper look at it and having watched a few of the video on mixing it seems like you'd use less of the Hxtal - mixing precisely what you need to coat a given area. I don't stabilize very often but I'm always struck by the amount of opticon that gets wasted pouring it in and out of the container and wiping off the excess etc. Would you agree with this assessment Lynn? I would definitely agree Tommy. I acquired mine the same was as Lynn did, From Helen. I still have half of what she sent to me (+ or - 1 oz of one and 0.5 oz of hardener) left and I have used it many times. I mix mine two to one and apply without heat then let it set for a week. It will soak into the tiniest cracks and set up like the rock. To make sure absolutely none is wasted I always have an extra slab or piece of rough I want to us it on so if there is a little left over I cover whatever I can with it. I have worked on a slab six or seven times with the excess before it is finished but I consider that one a free one. The only negative I have is if the crack is a tiny bit wide the glue will run out the other side. Masking tape is your friend when using Hxtal Jim
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gemfeller
Cave Dweller
Member since June 2011
Posts: 4,041
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Post by gemfeller on Nov 7, 2017 20:59:37 GMT -5
Thanks for the good tips people. zarguy, I like your idea of dispenser bottles -- I'll try to find some. And wampidytoo, thanks for the masking tape idea. It'll save lots of problems. rockjunquie, it really does go a long way. I've actually done about 15 big slabs and several cabs so far and have at least 75% left in my two 6o-gram bottles. That works out to about...let's see...1 gram equals 0.03527/oz., so times 120 it comes to about 4.23 oz. originally if I figured correctly. So that means I've used a little over an ounce. Not bad. And I do like wampidytoo does -- use every little bit each time I do a mix. I'm waiting for a few gembone slabs to completely set up before doing some test cuts to see if I'm getting results like zarguy.
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Post by Bluesky78987 on Nov 8, 2017 9:58:12 GMT -5
Very interesting thread y'all - the sticker shock also stopped me from using it, and I had a misconception that you had to use a vacuum pump with it. I'm all in on the "mix it up and paint it on" solutions!
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zarguy
fully equipped rock polisher
Cedar City, Utah - rockhound heaven!
Member since December 2005
Posts: 1,791
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Post by zarguy on Nov 8, 2017 9:59:02 GMT -5
Thanks for the post zarguy. Yeah I have to admit to getting sticker shock too with 8oz at $80 compared to 8oz of Opticon at $32. After I took a deeper look at it and having watched a few of the video on mixing it seems like you'd use less of the Hxtal - mixing precisely what you need to coat a given area. I don't stabilize very often but I'm always struck by the amount of opticon that gets wasted pouring it in and out of the container and wiping off the excess etc. Would you agree with this assessment Lynn? I've never tried Opticon. Hxtal costs $50 plus maybe $10 shipping for the smallest size. Split it with another lapidary friend & the $30 you spend will last a while & treat lots of slabs/cabs. Sell one $30 cab & you're home free. If you're near any of the dealers that carry it, you can avoid the shipping charge. I see there's one in Denver near I-70 & 25. If I need any when I'm there for the Gem show next year, I'll buy it in person. The stuff I bought from Helen was a 1:2 mix. This is designated as 1:3. She said they were the same thing, but wouldn't elaborate when I asked why the ratio was different. Lynn
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QuailRiver
fully equipped rock polisher
Member since May 2008
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Post by QuailRiver on Nov 8, 2017 14:17:20 GMT -5
When hardened HXTAL has a refractive index near that of most common types of glass. And it doesn't yellow with age as badly as many epoxies do. So it is a good choice for clear to slightly translucent agate or quartz, or other light colored stones. HXTAL and Opticon Fracture Sealer work best for treating tight fractures. But for wider cracks and gaps the less expensive two-part epoxy adhesives will work as long as you heat them up first to make them less viscous.
Epoxy 330 is a good water clear epoxy to use. And even some of the two part epoxies available at hobby stores can be used. I like the Bob Smith Industries brand. They make five, fifteen, twenty and thirty minute cure-time formulas. As a rule the slower the time cure formula the harder the cured epoxy is. And the slower the cure time the more time the epoxy has to saturate. I usually use the thirty minute cure epoxy. Heating the epoxy resins first does thin them so they saturate better but it also makes them cure faster than they do at room temperature. So you have to have everything ready and work fast.
To heat the two parts, if I only need a small amount, I use a scrap piece of window pane glass and just squeeze out the amount I need in two individual resin parts rows, spaced widely enough apart that when they start liquefying from heat they don't run together and begin hardening. I place the piece of glass with the epoxy on top of my leveled dop wax warmer and let it heat until it gets runny. Glass will not absorb any liquid from the Epoxy nor impart any contaminates into it. As the epoxy warms, the rows of resin will begin to spread. Once they have nearly stopped spreading it's time to mix them together and apply them to the stone. I do this with a 4" blade artist painting knife. Also it helps flow and saturation to have the stone warmed as well.
After applying the mixed epoxy to the stone be careful where you set it. The epoxy can seep through to the other side and glue your cab or slab to whatever is underneath. And if it's heated it can penetrate wax paper and adhere it, and the wax paper to whatever surface is underneath the wax paper (yes I learned this the hard way). So now for messier jobs I use wood shavings from my jointer or planner as a bed. Newspaper will work too. Either are easy enough to sand off if the glue seeps through but the wood shavings are easier to remove.
If I'm treating several stones and need a larger amount of epoxy than is practical to heat on a piece of glass then I use clean small metal food cans like tuna and salmon comes in.
Regardless of which type epoxy you use, a vacuum chamber can help with saturation. There are several posts and videos online on how to make one cheaply. I made the one for quick use using a plywood box and a small shop-vac for suction pressure. It worked okay but not as good as a chamber with an actual vacuum pump and valve that can hold vacuum pressure for longer periods of time will. I picked up a small vacuum oven cheap from a college surplus sale for this purpose but haven't gotten around to trying it yet.
Also should probably mention that I soak any slab or stone I'm going to treat with epoxy in lacquer thinner (not paint thinner) first to remove any saw oil residue.
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bmw2002
starting to shine!
Member since April 2017
Posts: 34
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Post by bmw2002 on Nov 8, 2017 14:52:41 GMT -5
Is the stuff sold on Amazon any where close to the benefits of HxTal? PC Products 70147 PC-Clear Epoxy Adhesive Liquid, 1 oz Double Syringe, Clear
The price between the two gives a big advantage to Amazon!
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TByrd
fully equipped rock polisher
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Member since December 2010
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Post by TByrd on Nov 9, 2017 14:25:00 GMT -5
I know a couple of master intarsia makers who use 10 minute epoxy, waxpaper, a toothpick, a heat bulb (in an articulating lamp) and get an entire intarsia completed in a couple of hours. Sounds like this process it a lot more entailed.
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Tommy
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Post by Tommy on Sept 10, 2018 20:07:32 GMT -5
Hxtal costs $50 plus maybe $10 shipping for the smallest size. Split it with another lapidary friend & the $30 you spend will last a while & treat lots of slabs/cabs. Lynn and everyone - I'm reviving this thread because I finally decided to break down and buy the minimum of Hxtal to stabilize some dino bone that I paid a pretty penny for and don't want to take a loss on and I was pleasantly surprised to find out that www.hisglassworks.com is now selling a smaller kit - 1.3 oz for $18. I made the purchase just now. It's still expensive for the volume and with the $13 shipping - but this puts it in the range of no brainer for me for testing purposes and if I end up using it up and liking it I'll feel a lot better about buying the 1/4 lb size. www.hisglassworks.com/shop/adhesives/epoxies/hxtal-nyl-1/hxtal-nyl-1-epoxy-adhesive-1-ounce-kit.htmlrockjunquieBluesky78987
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Post by Bluesky78987 on Sept 10, 2018 22:07:15 GMT -5
Excellent Tommy! Looking forward to your results!
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Tommy
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Post by Tommy on Sept 18, 2018 13:20:11 GMT -5
Couple of question for zarguy or anyone else who uses Hxtal - first of all how exacting are you when mixing? I'm reading the instruction sheet that goes with it and it is highly recommending using a digital scale because the stuff is "very particular" about it's mixture ratio and "measuring by volume is very inexact." Secondly and sorry if I missed anything about this in the earlier conversation but how well does this stuff work on general stabilization? IE: if I do the heat method and apply it over some tiffany stone that is too soft in places to work with, can I expect stabilizing type results like with Opticon?
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zarguy
fully equipped rock polisher
Cedar City, Utah - rockhound heaven!
Member since December 2005
Posts: 1,791
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Post by zarguy on Sept 18, 2018 13:50:01 GMT -5
I put it in squeeze dropper bottles that I buy at JoAnn Fabrics or other hobby store. I measure it out by the drop - 3 drops of part A to one drop of part B. Perhaps my drops aren't too precise since one part is thicker than the other. When I initially got it from Helen here on RTH, the ratio was 1:2. She said it was the same Hxtal, even though it used a different ratio. I've never mixed enough to do it by weight. A guy I met at the Denver show uses a vacuum and doesn't use heat, but lets it cure for a week or so. I'm going to try that method & see. Lynn
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Tommy
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Post by Tommy on Sept 18, 2018 14:17:08 GMT -5
I put it in squeeze dropper bottles that I buy at JoAnn Fabrics or other hobby store. I measure it out by the drop - 3 drops of part A to one drop of part B. Perhaps my drops aren't too precise since one part is thicker than the other. When I initially got it from Helen here on RTH, the ratio was 1:2. She said it was the same Hxtal, even though it used a different ratio. I've never mixed enough to do it by weight. A guy I met at the Denver show uses a vacuum and doesn't use heat, but lets it cure for a week or so. I'm going to try that method & see. Lynn Thanks Lynn - the size I bought came in two glass bottles with squeeze droppers but no measuring marks on the droppers as far as I can see. I'll try your drops method and see how it goes. I'm curious about the vacuum method too but not even sure what we're talking about. Does it require a chamber device or something like a vacuum sealed bag?
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Post by parfive on Sept 18, 2018 14:54:40 GMT -5
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