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Anders Rydstedt
02-20-2012, 06:54 AM
What exactly is going on when you blow opaque colors (k164) and half the piece (top or bottom) is a very different tone? Is this "striking"? Is it from heating more on one half than the other? I dont believe im over heating the color bar. Is there a trick to making an opaque piece (certain colors) without this effect? Any suggestions appreciated.

Pete VanderLaan
02-20-2012, 07:28 AM
It's more the heating of the piece after you have made it and are reheating it in the gloryhole. Repeated heats of the upper section when on the punty will indeed cause a strike if the glass is composed of materials that would be so inclined. Think Peach blow. Think Colloidal suspensions, think crystal formations.

Anders Rydstedt
02-20-2012, 11:28 AM
So is there something different about these opaques that strike? How can u tell which will do this, other than testing them all? Manufacturers arent saying anything about this.

Pete VanderLaan
02-20-2012, 12:15 PM
Testing is a great concept!

This is supposed to be art. I don't think it's the responsibility of the manufacturer to tell you anything beyond the linear expansion and whether it's toxic. I take note that when people find interesting effects from combining two commercially available colors, or more, that they don't immediately tell everyone what they have figured out. I explain to people how to get the best strikes out of my glasses if they ask but I'm not their mom.

David Patchen
02-20-2012, 01:32 PM
You're getting two colors for the price of one and you're upset about it?? ;) Think of it as a free incalmo.

Two things come to mind:
1. Sometimes the part of the rod that gets the most heat and wasn't exposed to the air has a different haze to it. I've seen people heat up rod and snip the very end off of it w/diamonds before they get to marvering to reduce this.

2. Work hotter and quicker so you don't end up with one part of the piece very cool and the other part of the piece really hot, which can change how the color behaves. (Working hotter and quicker will also make you a better glassblower, but that's a different thread.)

Edward Skeels
02-20-2012, 03:07 PM
"Is there a trick to making an opaque piece (certain colors) without this effect?"

There is a way but it's not a trick. It starts with the chemistry. Can't make a silk purse from a sows ear.

"Manufacturers aren't saying anything about this."

John Croucher said something about this and even melted a solution.

It's an esoteric conversation. Go to the GAS conference and there might be two or three people who care or get it, assuming they even show up.

+1 to Pete's answer re; reheat and responsibility.

Pete VanderLaan
02-20-2012, 03:25 PM
I'm taking Ed's curmudgeon's correspondence course through Brigham Young University. Those biblical references about sow's ears send tingles up my leg...

Rosanna Gusler
02-20-2012, 05:20 PM
I'm taking Ed's curmudgeon's correspondence course through Brigham Young University. Those biblical references about sow's ears send tingles up my leg...thats sciatica . rosanna

Pete VanderLaan
02-20-2012, 05:31 PM
well, that figures...

Rahman Anderson
02-21-2012, 06:30 PM
Just from someone well traveled... some set their bubble up with a big clear mass off the end when blocking...some go for even walls. I have seen both work but if the overlay is even then the mass is all at the bottom well...when the mass blows out the color is heavy on top and thin on the bottom. The old how do I stop blowing out the bottom. I was taught to cool it. Some are taught to put material there. I was taught more material will blow out more. But I see that thick ass bottom work for people all the time...? Some colors are just going to be prone to doing stuff other then be static. Please don't ask them to make all colors static. Or non interactive. Yes it is mostly ugly and expensive when not planned. But when it works...the sum is greater then the parts.

Michael Ahlefeldt-Laurvig
02-21-2012, 07:27 PM
Well , how you set the bubble up sort of depends of what you're making- what the end result will be,. Its not like there is one way to do it. But it did occur to me that the thickness of the color does play a part. I cant say that Ive run unto this problem with a lot of colors, but I have with a few. Have you tried using less color?

Michael Ahlefeldt-Laurvig
02-21-2012, 07:45 PM
Just from someone well traveled... some set their bubble up with a big clear mass off the end when blocking...some go for even walls. I have seen both work but if the overlay is even then the mass is all at the bottom well...when the mass blows out the color is heavy on top and thin on the bottom. The old how do I stop blowing out the bottom. I was taught to cool it. Some are taught to put material there. I was taught more material will blow out more. But I see that thick ass bottom work for people all the time...? Some colors are just going to be prone to doing stuff other then be static. Please don't ask them to make all colors static. Or non interactive. Yes it is mostly ugly and expensive when not planned. But when it works...the sum is greater then the parts.
Rahman- it seems to me by what you're writing that you are blowing too cold… if you're jacks are making marks and you're blowing out through the bottom of you're piece - then I would say that you need too work hotter- its sort of an unnatural thought that it would become more easy doing it hotter but its really true,- you have to push it!