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Josh Bernbaum 03-14-2019 07:57 PM

Iron Sulphide glasses?
Haven't posted in a while on this batching and color forum but still glad it's here..
So lately I've been pulling quite a bit of cane with Gaffer's "Durissimo Black", pulling again in murrini and then using that in my pieces. It's a steep learning curve to using the stuff, it's SO stiff, it barely feels like glass. I've got a pretty good handle on it now though. It's taken me a while but with some adaptations in process the pulls are now finally feeling almost (almost) like cane pulls with normal duro color in the core.

I'm going to be asking John a lot of questions at the class at Penland next month, but just curious if anyone here knows some more about the chemistry. I've heard that this stuff is an Iron Sulphide glass (or Iron sulfate?). I'm not sure if that's correct or not, but I do detect a sulphur-ish smell coming off of the chunks of the bar when I'm working with it. More specifically, it's not just that it smells when it's hot, but more so when I quench parts of it after heating. Even the water in which it's quenched smells afterward. Curious about what's happening here..

Jordan Kube 03-15-2019 01:26 AM

You can melt this yourself. Not as stiff.

Josh Bernbaum 03-15-2019 08:49 AM

Do you think there's rosin in Gaffer's version Jordan?
I'm also too worried to put sulphur in my furnace here, worried about lingering smells that is.. Even the selenium I've put in melts before seemed to linger afterward.

Pete VanderLaan 03-15-2019 09:15 AM

sulfur certainly sticks around. In a reducing atmosphere it smells for a long time. Rosin is not a requisite in a glass like this if you want the beer bottle brown. It's certainly does reduce though.

Jordan Kube 03-15-2019 07:03 PM

Just remember, Josh, you are made of stardust. Practically a living god. You need not concern yourself with such terrestrial things as the smell of sulphur.

Or: To quote Ed Skeels, "It's ok to have a pussy, it's not ok to be one."

Or: To quote Father Guido Sarducci "You won't be sorry for long."

Totally kidding but I tend to just go for stuff like this. Melt it as is.

Pete VanderLaan 03-15-2019 07:41 PM

"You can almost always get it out of the pot"

Pete V

Josh Bernbaum 03-16-2019 06:25 PM

Thats pretty funny Jordan. I've heard through the grapevine that Lino likes Gaffer's durissimo better than the rosin he used to use. That may or may not be true but I think it's true. Quenching this durissimo doesn't turn the water black or anything like that, not sure if that's an indication of whether or not there's rosin in there.

Jordan Kube 03-17-2019 02:37 AM

I believe it. It's a great glass but if you add in the duro stiffness it's probably even better. I wonder if John saw this formula and tweaked it. He wasn't working on anything like this when I talked to him in Corning at the GAS conference. Another note, this isn't a casing glass. Blows out garbage just like the duro. Only for cane work, threading, lip wraps etc. Melt it and make it into bar.

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