julieooly
Cave Dweller
Member since October 2018
Posts: 714
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Post by julieooly on Oct 16, 2019 16:52:08 GMT -5
Ok time for some doublet lessons please! Basically it looks like a doublet is simply one material glued on top of another then cabbed as a set. Right? So do you make the cab, then glue it to something and then rework it? Or glue two things together then cab it? I've got these two green moss and three super clean white Ochoco agates that I'm working on. I love how the white notebook paper makes the moss stand out, and I've seen some killer white Ochoco with a blue color showing through. I think I need just a few tips and I'll be good to go!
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Post by rockjunquie on Oct 16, 2019 16:56:08 GMT -5
I haven't actually worked a doublet, but my understanding is you glue the 2 pieces together then preform and cab as one. However, I don't see why you can't back a cab and then do them together again.
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Don
Cave Dweller
He wants you too, Malachi.
Member since December 2009
Posts: 2,616
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Post by Don on Oct 16, 2019 17:12:01 GMT -5
If you're making a doublet with two different stones, you will generally want to epoxy one to the other first, then cut and shape the cabochon. Use a good non-yellowing UV stable 2 part epoxy. Make sure both surfaces are clean and flat. I like to wipe each surface down with acetone. Allow the epoxy to fully cure before cutting the cabochon.
You'll want the backing stone to be cut much thinner than the top stone so your cabochons are not too thick. I try to slab my backing stones 2-3mm thick. thinner is better.
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Post by Bikerrandy on Oct 16, 2019 19:30:07 GMT -5
You can turn those into doublets. You'll have to pick out the material for a backer, and slab it about 1/8 inch thick. You'll also probably end up grinding those thinner as well once they are attached to the backer. I use 330 epoxy and let it set up for three days. Once cured, you cab cut the backer around the cab, cut it slowly. It doesn't hurt to have some of the backer sticking out, this way to can grind the edges the form one stone from the two, them re-grind and polish the entire cab. Here's some of my work.... www.facebook.com/pg/Rock-Hobby-282375391773191/photos/?tab=album&album_id=938382186172505
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Post by opalpyrexia on Oct 16, 2019 20:06:02 GMT -5
Here's a suggestion for the actual assembly (if the top cab is transparent or translucent and making the doublet not simply for strength) —
When mixing the epoxy, air bubbles will be introduced no matter how carefully you try to avoid them. Follow this easy trick to eliminate nearly all of them.
After mixing the epoxy and spreading it on your backing stone, wait a couple of minutes for bubbles to come to the surface. Then play a butane torch (one of the little pencil torches will do) across the epoxy a few times from about 5-6 inches away. You'll see the bubbles pop and disappear.
When you place your top cab down, try to pivot it down like a falling tree rather than simply dropping it onto the backing. This will also reduce the likelihood of additional bubbles. Then using pressure, work the top cab in a circular motion to ensure good adhesion and to squeeze out any excess epoxy.
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Post by opalpyrexia on Oct 16, 2019 20:36:17 GMT -5
One other suggestion — assuming that you're using epoxy 330 — you can place the assembled doublet under an incandescent bulb (if you still have one!) to speed up the curing process to 15-20 minutes rather than waiting hours.
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julieooly
Cave Dweller
Member since October 2018
Posts: 714
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Post by julieooly on Oct 17, 2019 9:30:58 GMT -5
I have Hxtal and have been stabilizing stuff this week with it. Still haven't cabbed any of the stabilized material though, gonna give it a good week to set up now that the lights are off. Any different tips for using the Hxtal for doublets?
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julieooly
Cave Dweller
Member since October 2018
Posts: 714
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Post by julieooly on Oct 17, 2019 9:33:00 GMT -5
You can turn those into doublets. You'll have to pick out the material for a backer, and slab it about 1/8 inch thick. You'll also probably end up grinding those thinner as well once they are attached to the backer. I use 330 epoxy and let it set up for three days. Once cured, you cab cut the backer around the cab, cut it slowly. It doesn't hurt to have some of the backer sticking out, this way to can grind the edges the form one stone from the two, them re-grind and polish the entire cab. Here's some of my work.... www.facebook.com/pg/Rock-Hobby-282375391773191/photos/?tab=album&album_id=938382186172505 Your FB is awesome. What are the dark blue and the purple backers?
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julieooly
Cave Dweller
Member since October 2018
Posts: 714
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Post by julieooly on Oct 29, 2019 14:29:38 GMT -5
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julieooly
Cave Dweller
Member since October 2018
Posts: 714
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Post by julieooly on Oct 29, 2019 14:32:44 GMT -5
Ok so here is one finished, I backed it with orange calcite. It's a little over 7mm thick which is way thicker than most of my cabs. Should I make the next ones thinner if they're relatively this small?
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Post by rockpickerforever on Oct 29, 2019 15:31:07 GMT -5
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dshanpnw
freely admits to licking rocks
Member since December 2020
Posts: 892
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Post by dshanpnw on Nov 6, 2023 13:34:54 GMT -5
Here's a suggestion for the actual assembly (if the top cab is transparent or translucent and making the doublet not simply for strength) — When mixing the epoxy, air bubbles will be introduced no matter how carefully you try to avoid them. Follow this easy trick to eliminate nearly all of them. After mixing the epoxy and spreading it on your backing stone, wait a couple of minutes for bubbles to come to the surface. Then play a butane torch (one of the little pencil torches will do) across the epoxy a few times from about 5-6 inches away. You'll see the bubbles pop and disappear. When you place your top cab down, try to pivot it down like a falling tree rather than simply dropping it onto the backing. This will also reduce the likelihood of additional bubbles. Then using pressure, work the top cab in a circular motion to ensure good adhesion and to squeeze out any excess epoxy. Nice tips with the torch since bubbles are inevitable and lowering the piece slowly. I'm trying a doublet with a rarer stone, bruneau jasper and expensive backing, optical quartz, and I would really like to get it right the first time since there are no do-overs.
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