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-   -   Color bubbles (http://talk.craftweb.com/showthread.php?t=10645)

David Patchen 11-03-2017 12:13 AM

Quote:

Originally Posted by Marc Carmen (Post 137191)
Josh, I'm dying to try the durissimo. If it's a similar formula to Nero duro then it's a lead free iron sulfide black. Iron sulfide glass is not only naturally stiff but also incredibly brittle. Old glass container literature mentions that it is a cheap and easy way to black glass, if only it didn't make such an impractically brittle bottle.

Man, I have sooo many bubbly black filigrana in my student work haha.

It's not just stiff, it's CRAZY stiff! Definitely the stiffest glass I've ever played with and makes the white duro feel like enamel. I gather on the new black the instant it stops moving, which is literally walking from the gh to the furnace. If you lose the core heat you're toast. If you don't transfer it directly to a stick you're toast. Gathers needs to be done before the previous one fully sets up. Pulls need to be really hot with a faster walk than usual. If you don't have the black poking out of the end of the setup and quench before you stick to the post, you're toast. It's actually super fun to work with because it's so quirky. I've not had great luck keeping it jet black--I think it might have something to do with our gh running a bit rich (maybe Pete can explain what's up w/this). It's been going graphite grey on me--I'm going a few things to try to avoid this. I've been pulling it into cane, then bundling the cane and making murrine. I haven't used the murrine yet, but it looks excellent.

If you're into twisty cane, definitely try some of this stuff, it's wild and so much fun.

Pete VanderLaan 11-03-2017 08:10 AM

I have not melted sulfide blacks so I'm not able to comment. Lino ran rosin blacks that were remarkable in themselves. Mine are simply chock full of oxides blotting out any color transmission. I would think Alumina is playing a major role.

Scott Benefield 11-03-2017 09:29 AM

I'd be interested in hearing how it looks when you push the Gaffer durissimo that far, David. Stiff is one thing (as Pete says, alumina will get you that) but if it doesn't stay jet black at a hair's thickness....then what's the point?

Lino's rosin black was all that, but the melts he was doing at the old Manifesto facility were kind of unpredictable. Very fine bubbles would only appear in the final application, but not in the initial cane pull--occasionally. It was impossible to know if you had a good melt until you had taken it that far, but by then you were stuck with whatever you had. Lots of it went into the landfill.

Pete VanderLaan 11-03-2017 09:46 AM

In the black that I periodically melt, I do pull the cane out into extremely fine thread and then taking two fingernails and run down the thread. If there's anything in it, including bubbles, you will feel them.
My larger question is really whether the gas is coming back out of solution or whether it's just in the finished rod as trapped gas. There's a difference. Color rod can be overworked.

Making color is actually really hard when you consider the standard you have to achieve . In the final analysis, it should be dense black as Scott says, or what's the point?

Kenny Pieper 11-03-2017 09:46 AM

Quote:

Originally Posted by Scott Benefield (Post 137195)

Lino's rosin black was all that, but the melts he was doing at the old Manifesto facility were kind of unpredictable. Very fine bubbles would only appear in the final application, but not in the initial cane pull--occasionally. It was impossible to know if you had a good melt until you had taken it that far, but by then you were stuck with whatever you had. Lots of it went into the landfill.

I have melted that black a couple of times with no problems. Its crazy how it catches on fire when it gets charged. I stays black that's for sure!

Eben Horton 11-03-2017 10:57 AM

Quote:

Originally Posted by Kenny Pieper (Post 137197)
I have melted that black a couple of times with no problems. Its crazy how it catches on fire when it gets charged. I stays black that's for sure!

Did you ever go back ?? ;)

Kenny Pieper 11-03-2017 11:55 AM

Quote:

Originally Posted by Eben Horton (Post 137198)
Did you ever go back ?? ;)

Back where?

Eben Horton 11-03-2017 02:50 PM

Quote:

Originally Posted by Kenny Pieper (Post 137199)
Back where?

Itís a joke ;)

Greg Vriethoff 11-03-2017 03:27 PM

Quote:

Originally Posted by Eben Horton (Post 137200)
Itís a joke ;)

A rather off-color joke, Eben...

(O)

Pete VanderLaan 11-03-2017 04:40 PM

black humor

Eben Horton 11-04-2017 09:10 AM

ďOnce you melt black, you can never go backĒ. - ancient color maker saying.

Rich Samuel 11-04-2017 11:06 AM

"Melting red? Better off dead." - more ancient color maker saying. ;)

Eben Horton 11-04-2017 12:29 PM

Quote:

Originally Posted by Rich Samuel (Post 137208)
"Melting red? Better off dead." - more ancient color maker saying. ;)

Truth! Hahaha

Marc Carmen 11-04-2017 06:54 PM

Quote:

Originally Posted by David Patchen (Post 137193)
It's not just stiff, it's CRAZY stiff! Definitely the stiffest glass I've ever played with and makes the white duro feel like enamel. I gather on the new black the instant it stops moving, which is literally walking from the gh to the furnace. If you lose the core heat you're toast. If you don't transfer it directly to a stick you're toast. Gathers needs to be done before the previous one fully sets up. Pulls need to be really hot with a faster walk than usual. If you don't have the black poking out of the end of the setup and quench before you stick to the post, you're toast. It's actually super fun to work with because it's so quirky. I've not had great luck keeping it jet black--I think it might have something to do with our gh running a bit rich (maybe Pete can explain what's up w/this). It's been going graphite grey on me--I'm going a few things to try to avoid this. I've been pulling it into cane, then bundling the cane and making murrine. I haven't used the murrine yet, but it looks excellent.

If you're into twisty cane, definitely try some of this stuff, it's wild and so much fun.

Thank you David! Copied and pasted into my notes. I'm sure you saved me some headaches

Pete VanderLaan 11-05-2017 07:55 AM

Mark talked about cad/sel reds in fluorine that started off compatible in his work and by the time he was done, they were no longer compatible. The effects of heating and cooling repeatedly in a glass does often change them. While John is really cautious about using Hagy seals to determine mismatch, those efforts can sometimes be defeated. The description of the black makes me think of those circumstances.

Marc Carmen 11-05-2017 12:37 PM

Quote:

Originally Posted by Pete VanderLaan (Post 137220)
Mark talked about cad/sel reds in fluorine that started off compatible in his work and by the time he was done, they were no longer compatible. The effects of heating and cooling repeatedly in a glass does often change them. While John is really cautious about using Hagy seals to determine mismatch, those efforts can sometimes be defeated. The description of the black makes me think of those circumstances.

I've worried about this as well. Theres definitely some crystal growth going on. Some of the FeS test melts I've done needed to be struck from a dark trans brown to that characteristic gritty graphite black, but only if the melt wasn't reduced enough.

I've never had compatibility problems though. Then again, the density of the color never requires more than a thin overlay or a fine cane.

David Patchen 11-06-2017 03:14 AM

Quote:

Originally Posted by Pete VanderLaan (Post 137220)
Mark talked about cad/sel reds in fluorine that started off compatible in his work and by the time he was done, they were no longer compatible. The effects of heating and cooling repeatedly in a glass does often change them. While John is really cautious about using Hagy seals to determine mismatch, those efforts can sometimes be defeated. The description of the black makes me think of those circumstances.

This is why I never use cad/sel colors in murrine. Too many heat cycles blows the fit. I got this tip from John C a decade ago.

Jordan Kube 11-06-2017 10:26 AM

Quote:

Originally Posted by Kenny Pieper (Post 137197)
I have melted that black a couple of times with no problems. Its crazy how it catches on fire when it gets charged. I stays black that's for sure!

Was the recipe similar to this one Kenny?

http://talk.craftweb.com/showthread.php?t=11375

Pete VanderLaan 11-06-2017 01:42 PM

If it catches fire, it's Lino's for sure.

Kenny Pieper 11-07-2017 04:49 PM

Quote:

Originally Posted by Jordan Kube (Post 137274)
Was the recipe similar to this one Kenny?

http://talk.craftweb.com/showthread.php?t=11375

Jordan I am at the Philadelphia Museum show now so I cant tell you if this is it or not. It looks about right


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