CraftWEB Hot Glass Talk

CraftWEB Hot Glass Talk (http://talk.craftweb.com/index.php)
-   General Hot Glass Discussion (http://talk.craftweb.com/forumdisplay.php?f=4)
-   -   Bucket of Spectrum white (http://talk.craftweb.com/showthread.php?t=12657)

Lawrence Tuber 08-25-2020 11:39 AM

Bucket of Spectrum white
 
1 Attachment(s)
I found a bucket with 50lbs of spectrum white glass in the studio. It looks like busted up sheet. I think I bought it in 2011 for a resident artist's project that never came to fruition. Does anyone know if it's 96 coe or what it is?
I'm attaching a photo. I'm wondering if it would be good for casting into Plaster silica, any insight appreciated.
LT

Pete VanderLaan 08-25-2020 11:46 AM

If you aren't mixing it with anything else, L.E.C. is irrelevant. Otherwise, test it against what you are contemplating mixing it with. A simple pull test should suffice.

The photo appears to show two distinct colors. Is that the case? If so, test them against each other.

Marty Kremer 08-25-2020 12:58 PM

Just looks dirty to me. Most fusers were assuming 96 from Spectrum (before they sold) and, unless they did something daring or stupid, they got away with it.

Greg Vriethoff 08-25-2020 01:14 PM

Quote:

Originally Posted by Lawrence Tuber (Post 148562)
I found a bucket with 50lbs of spectrum white glass in the studio. It looks like busted up sheet. I think I bought it in 2011 for a resident artist's project that never came to fruition. Does anyone know if it's 96 coe or what it is?
I'm attaching a photo. I'm wondering if it would be good for casting into Plaster silica, any insight appreciated.
LT

If it's Spectrum it's 96. Does the bucket have any labels?

You can cast with it. You'll probably have some minor surface devit issues, but nothing outside the norm.

Shawn Everette 08-25-2020 02:53 PM

Spectrum sold both stained and fusing glass. Bullseye has a stained line as well. System 96 was what was designated for fusing. Now Oceanside is using the names interchangeably.

Steven O'Day 08-25-2020 05:50 PM

If it is smooth on both sides it probably is fusing glass and would work. If each side looks different with striations, small seeds or texture it probably is window glass and will probably devitrify on fusing.

Like Pete said, testing is your friend.

I made an 2" sq pattern bar out of Spectrum 96 white without any problem, no devit but this was not in contact with plaster.

Marty Kremer 08-25-2020 07:49 PM

Does plaster contribute to devit?
I get devit going too slow through the 1300's and also (sometimes) from unifrax fiberpaper binder fumes.

Steven O'Day 08-25-2020 08:09 PM

I don't know. My experience is that there are more problems with devit and scummy surfaces when casting into plaster than when fusing on shelves or into frax and vermiculite board backed molds. Like most things there are a lot of variables and I've never run controlled experiments to see if it is the plaster or something else like different cooling rates or generally larger pieces or geometry or ? when using plaster.

Greg Vriethoff 08-25-2020 11:52 PM

Quote:

Originally Posted by Marty Kremer (Post 148570)
Does plaster contribute to devit?
I get devit going too slow through the 1300's and also (sometimes) from unifrax fiberpaper binder fumes.

The answer is yes, but not because of the plaster itself, per se. As you pointed out with the binder fumes it has more to do with with the off-gassing of materials. Chemical water in plaster investment can take a long time to burn out depending on several variables. How thick is the mold? How long did it soak at temp.? If you ramp up really fast to your casting temp. there may not be enough time for the water to dissipate before your glass starts to soften. Then you're in the devit range temp.-wise, so it's a perfect storm-type scenario.

Eben Horton 08-26-2020 08:24 AM

Quote:

Originally Posted by Greg Vriethoff (Post 148572)
The answer is yes, but not because of the plaster itself, per se. As you pointed out with the binder fumes it has more to do with with the off-gassing of materials. Chemical water in plaster investment can take a long time to burn out depending on several variables. How thick is the mold? How long did it soak at temp.? If you ramp up really fast to your casting temp. there may not be enough time for the water to dissipate before your glass starts to soften. Then you're in the devit range temp.-wise, so it's a perfect storm-type scenario.

Plus the thermal mass of the mold will keep you at the de-vit temp longer no matter what.

Lawrence Tuber 08-26-2020 08:38 AM

spectrum opaque white
 
Thanks for all the replies. It's all pretty uniform in color, some of the edges are a little pink, not unusual for some white glasses. The 2 color appearance is mostly due to lighting.
I have been doing a good amount of kiln casting into plaster silica arround 3 inches thick with gaffer lead billets, and thought I would try this glass since I have it. I know it will be of very different flow than lead glass and much more prone to devit. I am blasting surfaces so that is not a great concern.
I assume it is 96 glass, and am wondering about the COE as a basis for firing schedule.
Has anyone out there done thick plaster silica kiln castings with spectrum, and would like to share a schedule?

Pete VanderLaan 08-26-2020 09:48 AM

comparing Spectrum to gaffer billets is like comparing apples and Orangutans.

Shawn Everette 08-26-2020 10:24 AM

I'm going to assume no, but did you try out the gaffer billets? Rona put my plans with it on hold. On the plus side they seem to be back to full production with most things in ready stock. That or everyone's stopped working...


All times are GMT -5. The time now is 06:55 PM.

Powered by vBulletin® Version 3.7.2
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
CraftWEB.com. Opportunity Network. 2008. All Rights Reserved.