recycled glass question
 

Does anyone have an opinion whether this is a true statement? This was a facebook listing for a bead:

Up Cycled HEART of WISHES Focal ~ Bombay Sapphire Gin bottle glass in aquamarine and cobalt amethyst Corralejo Tequila bottle glass mixed with fine .999 silver for gorgeous reactions, fine silver droplets across the surface...
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Created by me, in my studio, in Todos Santos BCS Mexico.
With over 10 years of bead making experience, all of my beads are Properly kiln annealed, and professionally cleaned and shipped.
*You will receive the exact beads in the photo.
*Payment is due within 24 hr of auction end.
Shipping from Baja Sur Mexico. Please allow 3-4 weeks for delivery
Thank you for supporting Handmade.

I asked whether the glass from these two bottles were compatible and this is the response I got:

as long as you don't try to encase them and just lay them side by side.

Is this true? It was a really pretty bead but I can't see how this is a true statement.
-Elaine

That seems....Not quite right to me. I mean, just by chance they MIGHT be compatible, and I heard that a way to test if two types of glass are compatible is to make a stringer by laying the two types against each other and if the stringer bends while cooling then they're too far apart in compatibility, but I don't think that's what she's talking about.

Not true. If she didn't test compatibility (with the stringer test or more specific type of test) the bead is likely to pop in half where the two colors meet at some point in the future. Or just develop some really nasty cracks.

Encasing or not is a whole nuther' compatibility issue.

My opinion is that recycled glass shouldn't be mixed, even two bottles from the same brand. There is no way to know the glass compatibility and sometimes it takes a long time for the stress to break the bead. I wouldn't want to send that out into the world and risk disappointing the customer a year later when it cracked.

Well, that's what I thought. I'm not one to call people out on stuff but I was feeling sorry for the person that paid a high price for that bead.

You didn't mention how high the price was.

I personally would be OK with spending something under $25 including shipping for something that was really pretty but I would only buy one (or make one) for myself or the Wifeunit because we know what to expect from it and are willing to take the risk.

I, again personally, would not sell a bead made from two different bottles even if they were only hot sealed side by side.
Even the small odds of a properly annealed bead like that breaking are too large to expose an unsuspecting buyer to.

Recycled glass is just too unpredictable.

Is the bottle glass compatible? Probably. There isn't a huge range of composition in typical, contemporary bottle glasses.

Is the statement she made about laying the glasses side by side accurate? Maybe.

You asked if the two glasses were compatible. They may be compatible enough to work the way she is using them, but as she stated, not good enough to work if one is encased with the other. Glasses with differing COEs and strain points can be made to work together depending on how they are used. Side by side is probably the most benign way to join them. Encasing one with another is definitely not.

I have a little bit of experience with this. Back in my scientific glassblowing days I sometimes had to make graded seals to join 33 COE boro to 90 COE soft glass. The transition between the two is typically made with several intermediate glasses in between. Done right, the pieces hold together just fine.

Two standard bottle glasses are likely to be closer in compatibility than any of our transition glasses were. But since you can't test the glass yourself, you can't know for sure how close - or far off - they might be, other than taking a look at the piece using a polariscope. So I agree with Phill - if you like the piece and it wasn't terribly expensive, go for it. If the cost is too high to risk, pass it by.