Putting encased Gilson Opals into marbles
I encased the opal in 11mm heavy walled tubing, with no bubbles and put it into the kiln. Then I made my marble, puntyed up to the back, heated the heck out of the lens and pushed my encased opal into it - melted it in with no air bubbles, rounded it, annealed it and then examined it. Surrounding the opal is a circle about 1/2 inch in diameter, where I assume the glass holding the opal ends and the glass that I made the lens with begins.
How do I get rid of this ring? For the first marble I did like this I used 15 year old tubing that I got from Wale (pyrex) to encase the opal, and the rest of the marble I made with Simax. I figured maybe the pyrex and Simax weren't compatible enough, so I encased another opal in Simax (using rods of Simax, which worked fine - no bubbles). I got the same result - a ring around the opal where it's glass encasing joined with the lens. Any help available out there for me? |
I get it when using 2 pieces of clear. I think it's scuzz.
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Its an artifact line. You can see it in clear glass where a hot piece meets a colder piece. I'm not sure there is anything you can do about it. I've tried super heating a marble to white hot and it did make the artifact line better, but I can still see it. Maybe someone here with more experience can teach us both a trick to fix it. :)
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What helps me in this technique is after I encase the opal in the tube I skim the outside layer of glass making sure it is clear of bubbles and scum I also make sure the lens of the marble is free of bubbles and scum then when I put the two together I make sure both pieces are hot and this help me, hope it helps you. :)
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Sounds like MK is right on. I to have done this and super heated it and even try-ed to move it around a little and made it better but still there.
I don't think it compatible i know mine wasn't it was just the temperate difference i have done other after that and got both piece up to the same temperate melted in and not pushed in and it was clear as a bell. if your not sure about the two different glass i would melt off a empty ball of the tubing and add it to a ball of your other glass at the same temperate and see how clear it is. I would wait and see if others might know a way. i wanted my opal some my answer was to bring it back up in the kiln and pull the opal and all the bad glass off. clean ever thing up make a smaller marble clean up the opal and use it in a different piece. good luck |
Wow, someone gave me a big chunk of this opal at the last show I did, I have never used it before. I had been planning on just sticking it to a hot Maria and then quickly encasing it with another rod of molten glass. Would that not work?
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hi Mary K, I recently had an opportunity to practice with opals. I believe you have to treat them like dichro (no direct flame on opal or all the pretty goes away), except there is no coated side you can heat.
The tube encasement method was pretty easy and I don't ever use tubing so that's saying something. |
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If you want let me know and i can start a new thread and give you tip before you encase that baby. |
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after you encase the opal pull the tubing into a stringer with the opal at the end this leaves just a tiny layer of glass around the opal and strips off any scum on the outside, it also makes it rather easy to place the opal
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^^ ok i did that, Morgan and as soon as i pulled off almost all the excess glass, what little glass remaining around the opal bubbled and scuzzed (like it was the most scratched and pitted glass before peeling) like crazy as soon as the flame touched it (when i was placing it).
any ideas? |
Larry: Good information. I thought about it and did my next marble working 'forward' with
the opal. Absolutely no lines, and the opal is way down deep in the lens. Thank you. Jerry K. |
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no problem. Your lenses will be cleaner as well if you touch them as little as possible. |
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Ok, I'll bite. So, for the rest of us who don't/can't read between lines, what does this "forward-working" technique involve. I'll settle for one more hint if you can spare it.
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artifact line
Hi,
you where talking about artifact lines in clear glass - and when I understood that right it is not clear how they appear or how they can be avoided. Here is a little science.. When you hold glass into the flame the flame glows orange - sodium (and who knows what else) in evaporating from the glass. Sometimes - while working very hot with a pointy flame you will find a little haze around it - which is sodium haze that condensed on the colder glass around the working point. So the glass changes in the flame. On the surface like just described - but also inside the glass a lot. Mainly due so called sodium migration. As a rule. The hotter the glass, the stronger the flame and the more/longer you have glass is in the flame - the more the glass changes! In the here described case it has nothing to do with the opal. It is only the clear glass and the flame that causes this effect. Of cause the two different kind of Boro that where used will make a difference. But the main thing... - Sealing the opal in the tube first, lots of heat was used. - Then later a big solid clear was heated a lot in the flame - the glass on the surface changed a lot (mainly sodium lost)... - ...and then the opal was squeezed into that. - Doing that a lot surface glass gets pushed away (similar to the head making a mushroom bead) and gathers in a circle around the opal. So here we are - a circle around the seal with a lot of changed glass. And this glass simpy has a different refraction index then the boro around it. That is what gets visual as these lines. There is not much to do - since you can melt glass without a flame! Best is Larry's advise - working backwards. Otherwise try to keep it in mind the glass changes in the flame and when it matters work cold and in a smooth flame. But very often it is a contradigtion of what you where planing to do.... Hope this helped a bit - sorry about my poor English. It's not my first language! |
^^^ -- very good explanation of WHAT it is, but still would like to understand how one works "backward".
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What I meant with working backwards (to avoid artifact lines - and, sorry, maybe this was misleading, I have no clue about opals:oops:) is.... Better start BIG and remove glass then start SMALL and the add glass. |
Thank you....sounds like the hint I needed...
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This is an old thread, but I am an old person. I just bought my first opals. Any advice? I got spheres as I was told those are the easiest.
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Us old folks gotta stick together Mary. Your bump of this thread got me thinking about it all over again - especially the forward/backward thing. I haven't yet gotten back up to speed in the new studio, nor have I purchased a single opal yet, but I'm planning on doing the tube encasement as stated, but instead of pushing into the face of a marble I'll try imploding it from the other end. Watcha think?
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Opal encasement
Hello fellow marble artist. I'm hoping to get some help with opal encasement.
I understand that I need to use tubing to encase the opal. How do I place it in the marble after the encasement? Do I attach the encased opal to a rod and place it through the lense letting the rod get encased in the marble as well as Itge opal or do I push the encased opal in using a tool leaving a void that I close slowly by heating? Thanks so much! |
When I did it by putting it into the lens you
Could see the clear glass from the tube I used To encase the opal. So I tried my next marble by Making the opal the very first thing that I put onto the Maria, and compressing it up a little into the Maria, and then putting onto the Maria Petals and leaves, or fuming the maria or whatever. |
Gerald, did the second process help? any trapped air/bubbles?
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The second way - putting the encased opal into the maria before starting to lay down your lines to make a flower - did not result in any air bubbles, however neither did the first way - after making the flower, shoving the encased opal into the top of the lens.
If one is having a problem with trapping air bubbles right up against the opal while encasing it using a tube, I just watched (9/03/2017) a video on Youtube by Revere Glass on how to encase an opal in a tube - it is excellent (thank you Dustin Revere). |
Thanks Gerald I will make a note to watch this later.
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I can’t wait to try an implosion marble with an opal! Thanks for the inspiration!
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