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View Full Version : G-183 and SP Batch question


Josh Bernbaum
10-28-2011, 02:00 PM
OK I know opaque reds/yellows can be problematic, but I've got a couple questions so thanks in advance:

Has anyone had compatibility issues with Gaffer's G-183 (taxi cab yellow)
and SP 87? Just wondering now because a recent piece I made developed cracks around some G-183 veil cane. These are pieces where I'm casing a pickup that's rolled up on a collar and then inflating and shaping.

What's different about the 3 other pieces I've made previously that are very similar and have not had problems is that the G-183 veil cane sections in those were from an older bar I had and the problem piece was made with cane from a chunk of a newer color bar. Or perhaps a bit more color was concentrated in the section of the cane pull that I cut up to use for this one?

I'm suspecting this color is "borderline compatible," I've had no problem with it for regular overlays on blown work. I've heard folks say here that the LEC/COE can change a bit with multiple heatings (like for cane).

I do plan to do some polariscope looking which I haven't seemed to need to do for a long time until now. Is looking at a cross-section of the cane enough of a clue, or do I have to somehow look at the finished piece between the 2 filters?

Lastly, is it odd that this problem piece was fine coming out of the annealer and I didn't see the cracks develop for a couple of days? (hadn't even put on the grinding wheel yet)

Richard Huntrods
10-28-2011, 02:21 PM
Well, this is probably no help due to the age, but...

I got a bar of that taxi cab yellow at Red Deer Series in the mid-to-late 1990s, and every single thing that I made with it that week cracked completely to bits within a few months. Some things didn't survive the week.

I tossed the remnant and never bought or used it since for obvious reasons.

-R

Pete VanderLaan
10-28-2011, 04:38 PM
Bright reds and yellows are always tough since they contain no lead at all. I have seen pieces take virtually months to break from incompatibility including in my own work.

If you have a decent polariscope I can teach you how to make hagy seals. The really good ones like the one Croucher and I both have run over $2K but they are really exacting tools

David Patchen
10-28-2011, 04:40 PM
the LEC/COE can change a bit with multiple heatings (like for cane).

I think the cal-sel colors like this, some oranges and reds are the ones that can shift when they are heated and cooled. I think they can work ok as frit and overlays but if you're using them as cane I think you're really gambling.

When I need yellow cane I make veiled cane with a center of enamel white, strip of clear, then overlay of a transparent yellow--they don't have the same chemistry as the opaques. I've never had trouble with Gaffer Yellow, Daffodil or Citron (all the ones I'd consider in the yellow family).

Plus, veiled cane looks 100 times cooler than opaque cane, but that's just my $.02. Other than black and white I always make veiled cane with transparent colors.

Josh Bernbaum
10-28-2011, 08:18 PM
When I need yellow cane I make veiled cane with a center of enamel white, strip of clear, then overlay of a transparent yellow

Thanks David,
Just out of curiosity, why the strip of clear b/w the white and the trans. color?

Josh Bernbaum
10-28-2011, 08:23 PM
If you have a decent polariscope I can teach you how to make hagy seals. The really good ones like the one Croucher and I both have run over $2K but they are really exacting tools

Thanks Pete,

I will take you up on that offer at some point soon.

How 'good enough' would my checking cross-sections of the cane I make with 2 polarizing filters be, or would it still be necessary to check the finished piece for stress?

Travis Frink
10-29-2011, 03:13 AM
G100 has lead and will foul (yucky black) cad sel yellows oranges and reds unless you put a layer of clear (or some unleaded) in between. Found that out the hard way when I thought all G opals and solids were lead free- some are not.

A couple years ago, I made some awesome tiger murrini with Taxi cab yellow and had some problems with the murrini cane cracking but had no problems with breakage in the pieces it was used sparingly in. Part of that may be due to multiple heat cool cycles as I made parts on different days to be assembled later. Another factor was no doubt using colors from 3 diff makers- the lead free black seemed suspicious at the time. Another factor is that solid yellows and oranges crack really easy on me if I let them get as cool as other colors (like for punching and late bitwork and so on) and the murrini did not get into the annealer as soon as it maybe should have. Another factor....

UnAnnealed cane will look colorful under the polariscope so make sure you look at annealed cane.

Pete VanderLaan
10-29-2011, 06:45 AM
Well, this is probably no help due to the age, but...

I got a bar of that taxi cab yellow at Red Deer Series in the mid-to-late 1990s, and every single thing that I made with it that week cracked completely to bits within a few months. Some things didn't survive the week.


************
The early formulations for that color were totally different than what has been produced in recent history.

Shayna Leib
11-08-2012, 09:53 PM
Hi Josh,

I'm not sure if you're still looking for an answer to this question, but if anyone else is, here's my opinion. I work with all kinds of opaque yellows, and the Gaffer Yellows are testy. You absolutely have to bring them up to 1050 before you'll even have a chance of them turning out. In case your pyrometer is off, I usually bump it up to 1070 or 1075. They WILL NOT FIT if they aren't picked up at this temp. If you feel like throwing away some color, try one pickup at 950, and one at 1070 with the same bar, and you'll see. I might even go so far as to do this with Reichenbachs also. It will mess up your warmer if you also have soft colors you're working with at the same time, so plan your slot accordingly or garage your softer colors first before bumping up the warmer to 1050+.

I also agree with the others about the use of cane. One annealing cycle of cane, including air annealing is compatible with base glass. Two annealing cycles make the cane marginally compatible. Three is simply out of the question. SP87 is rumored to be 2 degrees off of 96, as is Spectrum, which is 2 off the other direction. Best use Gaffer Batch if it's important.

There has also been a re-formulation of the Taxi due to China's increase of ingredients used to formulate, and these days it's nearly fluorescent. You can still buy Reichenbach orange/yellows, but I don't think you'll be able to for much longer.

Hope that helps.

Shayna

Zach Jorgenson
11-08-2012, 11:30 PM
Gaffer recommends a soak temp of 1110˚F for opals before pickup.
http://gafferglass.com/technical/blowing.htm

Kenny Pieper
11-09-2012, 09:42 AM
Hi Josh,

I'm not sure if you're still looking for an answer to this question, but if I work with all kinds of opaque yellows, and the Gaffer Yellows are testy. You absolutely have to bring them up to 1050 before you'll even have a chance of them turning out. In case your pyrometer is off, I usually bump it up to 1070 or 1075. They WILL NOT FIT if they aren't picked up at this temp.


Shayna

This may keep the color from cracking when transferring to the gloryhole but will not have an effect on the final expansion/compatibility issue.

Pete VanderLaan
11-09-2012, 11:15 AM
This may keep the color from cracking when transferring to the gloryhole but will not have an effect on the final expansion/compatibility issue.
*********
Thank you Kenny! ( mumble mumble)

Edward Skeels
11-09-2012, 02:36 PM
*********
Thank you Kenny! ( mumble mumble)

really

also; don't assume repeated annealing will make glass more compatible. At most it might (maybe, tiny chance) change the structure of a glass but not neccesarily in the direction you want and not with the certainty suggested.

Need a new kachina over the furnace door.

Pete VanderLaan
11-09-2012, 04:35 PM
well, I did fire off this particular new theory about glass to John Croucher this morning. Inquiring minds want to know what the Kiwi thinks..