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Post by frane on Oct 16, 2018 20:42:06 GMT -5
Hi all, It has been over a year since I touched all my cabbing equipment (or logged in) but it is time to get back to it. I have some opal that is very thin. once I find the fire, which won't take much, I want to either use Girasol opal for top and bottom or some clear quartz. What do you use for a binder adhesive that won't yellow? Do I take the opal to a higher polish or does it matter when using a binder so maybe just find the fire? I have never done this and I know people that I used to see on the board had, so please, attach threads or let me know what you use so I can try to make this work.
Thanks!
Fran
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NDK
Cave Dweller
Member since January 2009
Posts: 9,440
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Post by NDK on Oct 16, 2018 20:49:40 GMT -5
Hi Fran, good to "see" you again! I've never made a doublet but I do know you want to use a clear epoxy, I believe 330 is the highly recommend stuff to use. I don't think you need to go past 600 when doing the doublet but I'll let someone with more knowledge chime in on that. I also believe there's a tut on here somewhere on how to make a doublet. I think weeshan wrote it up many moons ago. Take care! Quick edit: here's Shannon's tut: forum.rocktumblinghobby.com/thread/32781/doublet-triplet-tutorial
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Post by Rockoonz on Oct 16, 2018 23:33:07 GMT -5
The tutorial is great. The only thing I'll add is that your opal should end up much thinner than the moss agate in the tutorial. Carefully grind to the band of fire, epoxy the basinite to the opal, then grind it down till you hit the fire from the other side, then epoxy the quartz on. Stir your epoxy without lifting your stir stick from it to prevent air bubbles, and wave a butane lighter or torch over to lift bubbles out. join pieces like you close the cover on a book to force air out of the end. Give the epoxy lots of time to set between steps.
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Post by frane on Oct 18, 2018 18:14:03 GMT -5
Thank you both so much! This really helps a lot. Now I just have to tune up my cabbing machine and my flat lap so I will be ready to get at it.
Fran
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NRG
fully equipped rock polisher
Member since February 2018
Posts: 1,630
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Post by NRG on Oct 18, 2018 19:34:50 GMT -5
The tutorial is great. The only thing I'll add is that your opal should end up much thinner than the moss agate in the tutorial. Carefully grind to the band of fire, epoxy the basinite to the opal, then grind it down till you hit the fire from the other side, then epoxy the quartz on. Stir your epoxy without lifting your stir stick from it to prevent air bubbles, and wave a butane lighter or torch over to lift bubbles out. join pieces like you close the cover on a book to force air out of the end. Give the epoxy lots of time to set between steps. One can degass their epoxy using a canning jar and brake line vacuum bleeder pump. And the HXTal that we all have been discussing lately is perfect for this. It has a very long gel time. It's super strong. Doesn't yellow. The pros who use it a lot, mix it in glass jars so the can see the mixing. Because of the long gel time, cleanup is easy in glass with acetone. Haven't bought any yet, but I'm already a fanboi
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Post by Rockoonz on Oct 18, 2018 20:21:00 GMT -5
The tutorial is great. The only thing I'll add is that your opal should end up much thinner than the moss agate in the tutorial. Carefully grind to the band of fire, epoxy the basinite to the opal, then grind it down till you hit the fire from the other side, then epoxy the quartz on. Stir your epoxy without lifting your stir stick from it to prevent air bubbles, and wave a butane lighter or torch over to lift bubbles out. join pieces like you close the cover on a book to force air out of the end. Give the epoxy lots of time to set between steps. One can degass their epoxy using a canning jar and brake line vacuum bleeder pump. And the HXTal that we all have been discussing lately is perfect for this. It has a very long gel time. It's super strong. Doesn't yellow. The pros who use it a lot, mix it in glass jars so the can see the mixing. Because of the long gel time, cleanup is easy in glass with acetone. Haven't bought any yet, but I'm already a fanboi I've used Opticon and 330 epoxy, haven't tried the HXTal yet. I wish I woulda kept the My-te-vac when I switched to a power bleeder, but I didn't. Guess I need to watch the swap meets. The butane lighter torch pulls out the bubbles every time for me, though.
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Post by opalpyrexia on Oct 18, 2018 20:42:24 GMT -5
I don't think you need to go past 600 when doing the doublet but I'll let someone with more knowledge chime in on that.
600 grit is good advice. I would stop there to ensure that the surface is still rough enough for the epoxy to grab well.
An optional step you might want to consider is to get some carbon black pigment to blacken the epoxy used to attach to the backing stone. It's not necessary, but it can help to hide a few bubbles. Here's a 3-gram example on Amazon — that would be a lifetime supply for someone specializing in doublets because it takes a very tiny amount to turn the epoxy black:
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NRG
fully equipped rock polisher
Member since February 2018
Posts: 1,630
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Post by NRG on Oct 18, 2018 21:59:03 GMT -5
I don't think you need to go past 600 when doing the doublet but I'll let someone with more knowledge chime in on that.
600 grit is good advice. I would stop there to ensure that the surface is still rough enough for the epoxy to grab well.
An optional step you might want to consider is to get some carbon black pigment to blacken the epoxy used to attach to the backing stone. It's not necessary, but it can help to hide a few bubbles. Here's a 3-gram example on Amazon — that would be a lifetime supply for someone specializing in doublets because it takes a very tiny amount to turn the epoxy black:
Just a tidbit of info. The pro "cold worked glass" folks usng HxTal will polish all pieces before applying the epoxy. They are significant more sophisticated than we are. They also use a siloxane "bonding agent". It's essentially 3d intarsia.
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Post by hummingbirdstones on Oct 18, 2018 22:16:27 GMT -5
Holy smokes, those are gorgeous!
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NRG
fully equipped rock polisher
Member since February 2018
Posts: 1,630
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Post by NRG on Oct 18, 2018 22:24:05 GMT -5
Holy smokes, those are gorgeous! For $30k they better be!
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Post by hummingbirdstones on Oct 18, 2018 22:44:29 GMT -5
No snit! When I win the lottery tomorrow I can afford to buy a couple.
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Post by parfive on Oct 18, 2018 23:13:29 GMT -5
I use Krazy Glue for doublets. No mixing, no bubbles to worry about, no vacuum chamber. And it’s thin, making it easier to work with in my book. Did this cab over ten years ago. Just dug it out see if it’s yellowed at all. Nada. Looks the same as the day I finished it. Graveyard Point on basanite.
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Post by opalpyrexia on Oct 19, 2018 10:22:55 GMT -5
I use Krazy Glue for doublets.
So, you're an adherent of cyanoacrylate, and you're sticking to it?
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Post by Rockoonz on Oct 19, 2018 10:23:43 GMT -5
I use cyanoacrylate (krazy glue) type adhesives with intarsia that doesn't incorporate metal, but not for backing or capping, just because that's the way I was taught. My doublets and triplets teacher (will be helping to process his estate today) only used 330 epoxy, didn't like cyanoacrylate glues because if you set the stone and it gets heated when polishing the metal it will get cloudy. This has happened to my wife with a triplet we bought for a pendant she made. I face my pieces using 180 grit and since the epoxy is optical and fills the scratches it is identical to one taken to 600. Only the outside needs to be polished. The important thing is perfect flatness, accomplished by not moving the piece on the lap while sanding, I place it on the wet lap while it is off, turn it on with the piece held to the lap, and turn it off before removing. With pieces that need a lot of material removed I don't do this until it's getting close, since it takes so much longer and can wear the laps unevenly.
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Post by opalpyrexia on Oct 19, 2018 10:46:02 GMT -5
I use cyanoacrylate (krazy glue) type adhesives with intarsia that doesn't incorporate metal, but not for backing or capping, just because that's the way I was taught. My doublets and triplets teacher (will be helping to process his estate today) only used 330 epoxy, didn't like cyanoacrylate glues because if you set the stone and it gets heated when polishing the metal it will get cloudy.
I think that puts the concerns in proper order: bubbles, discoloration, and strength. The strength of the bond is virtually never an issue, so stopping at 180 or thereabouts makes sense (as long as it doesn't contribute to bubbles). Why spend the additional time with finer grits?
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