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Mark Dolan
01-02-2012, 09:25 PM
I have been melting Spectrum 96 pellets with a transparent dark amber colored piece of Kugler color bar I found at the bottom of my bag. ( I don't know the exact number). Everytime I use this color I get a curly-cue like effect at the top of the bubble when I gather over it with clear. I have also had trouble with this same color blowing out too thin on the sides. Is this a sign of color incompatibility with the System 96 or perhaps I'm working too hot with this delicate color? I have not had similar problems with the Cobalt Blue transparent Kugler Color bar (k41).

Jordan Kube
01-02-2012, 11:07 PM
Operator error.

Mark Dolan
01-03-2012, 09:51 AM
Very possible Jordan. I was hoping maybe someone would offer a suggestion on how to resolve the issue.

Scott Novota
01-03-2012, 10:09 AM
Let that color get really cold before you gather.

Also, you are gathering top down. Most of these guys gather from a large side port in a big furnace and will have a different host of issues.

Gathering top down from above you slough off more glass than a side gather and if the glass is a low melt(read high lead most likely) color it will drain off into the pot and give you that curly cue kind of color bleed at the end.

Also look into having a lower working temp. Is your glass working temp more than 2100? That would cause quite a bit of it to run off the pipe as well.

Just suggestions. Good luck.

Patrick Casanova
01-03-2012, 10:10 AM
Marc,

It is not a sign of incompatibility... it is a viscosity issue. The curly cue is caused by the overlay color getting soft and the top surface actually moving with the drag created by gathering and trailing off as you let the excess glass from your gather drip back to the surface of the pot. Let it get colder and gather faster if this is a problem and you should not have an issue. As to the color getting too thin; you may not be applying the overlay as evenly as you think, or depending on the shape you are going for you may need to set the color up differently leaving more color on the sides of the bubble so it is denser when blown out. Practice will reveal what is needed with each color and different shapes.

Mark Dolan
01-03-2012, 10:29 AM
Yes, I gather from the top and my working temp is 2150 degrees. i will let the color cool a little more before gathering and I'll lower my furnace temp a bit as well as you suggest. Thanks for the input!

Scott Novota
01-03-2012, 11:35 AM
Mark,


I run right around 2120f in mine if that helps at all. The lower the temp the more you will gather with less run off.

I will run it up to 2150f for goblets so that I can pull really hot bits from the side of the pot but everything else is right at 2120f 90% of the time. It is quite amazing how much difference in the amount of glass you will get in just a 30f difference.

Edit:
The center of your pot will be a bit cooler than the walls if it is anything like mine.

Mark Dolan
01-03-2012, 11:48 AM
Thanks Patrick. I pick up the color in the kiln with a collar and then melt it in the GH as opposed to the overlay method. Do you think in this instance with this color, the overlay method would create a more even application of the color?

Mark Dolan
01-03-2012, 12:02 PM
Thanks again Scott. I did notice the glass was dripping off the pipe rather quickly this weekend. Do you have any issue with the glass becoming stiff at 2120 degrees? One of the concerns I've read about using Spectrum 96 pellets is it's shorter working times. I have not noticed this at 2150 degrees, although I have little to compare against.

Michael Mortara
01-03-2012, 01:00 PM
We charge/fine system 96 at 2140, blow at 1990. You are burning up dollar bills left and right at those temps......

Scott Novota
01-03-2012, 04:24 PM
Overlay without a doubt.

The smaller furnace is going to be a cooler pull than a large furnace at the same temp reading on the termocouple. The thermo is on the outside of the pot really close to the elements and the heat needs to transfer though the pot to melt the glass.

I believe the center of my pot to be around 2100f, and the wall to be around 2110f with a temp on the outside at around 2120f reading on the thermocouple.

Just a WAG on my part. I can tell you without a doubt the 150lbs furnace at 2130f is really really soupy compared to my 2130f.

Pete VanderLaan
01-03-2012, 04:48 PM
Thanks again Scott. I did notice the glass was dripping off the pipe rather quickly this weekend. Do you have any issue with the glass becoming stiff at 2120 degrees? One of the concerns I've read about using Spectrum 96 pellets is it's shorter working times. I have not noticed this at 2150 degrees, although I have little to compare against.
*************
Are you remelting the same clear cullet multiple times? It gets shorter every time you do it. Cordier too.

Scott Novota
01-03-2012, 05:12 PM
If you do just stick up the color without an overlay....which I do from time to time.

After you have melted in the bar to the form that you like where you would normally blow your starter bubble stop.

Now get it nice and ripping hot then let it cool all the way down at least one time. I would recommend twice just to get a really even heat before you put your starter bubble in. Then put one in that is about the size of a grape. Let it cool all the way down again and put a small strip gather on it. Blow it out a bit more then cool again then have your way with it.

It is the only way this guy can get anything close to a even blow out from a non-overlay piece of color. Trust me when I say I am no master at it and don't take it as the word of an expert but it is what works for me.

David Patchen
01-03-2012, 05:51 PM
After you have melted in the bar to the form that you like where you would normally blow your starter bubble stop.Now get it nice and ripping hot then let it cool all the way down at least one time. I would recommend twice just to get a really even heat before you put your starter bubble in. Then put one in that is about the size of a grape. Let it cool all the way down again and put a small strip gather on it. Blow it out a bit more then cool again then have your way with it.

I think this is really good advice. I've seen people struggle with uneven bubbles and most of the time it's because they've got their color/bubble only ripping hot on the surface, but not on the inside. (Known as a 'honey-covered rock'). What Scott describes will help ensure the glass is hot through and through before you go trying to pop a bubble in it. I'd also add that after you take the heats he describes, give the glass a quick and even roll on the marver or blocking to give it a skin before you pop your bubble. This will give you a bit of a cool skin and prevent things from going totally haywire.

Mark Dolan
01-03-2012, 08:27 PM
Great advice Scott and David. Can't wait to give it a go this weekend!

Mark Dolan
01-03-2012, 08:31 PM
I have avoided remelting as I have read you need to go above 2400 degrees to successfully remelt. I'm hesitant to take my little wire melter over 2300 degrees.

Pete VanderLaan
01-03-2012, 08:55 PM
I have avoided remelting as I have read you need to go above 2400 degrees to successfully remelt.
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Wherever did you read that?

Mark Dolan
01-03-2012, 09:48 PM
The part about not going above 2300 degrees comes as advice from people who own this particular furnace and is an attempt to prolong element life I am sure. The part about remelting at temperatures above 2400 degrees comes from System 96 website Q and A section. See below


Q I am re-melting Spectrum glass and using it for blowing. Is there any danger from breathing the fumes?
A It depends on when you choose to breathe the fumes! During the re-heating process, at temperatures of 2450-2500F (required to re-melt our glass), there will be some measurable "gassing-off" of volatile materials. Commonly, this gas is directed from your furnace or melting chamber up and out a flue designed for this purpose. At these temperatures, if you hold your face over the flue (or the molten glass) and breathe deeply, you are in danger of both ingesting some nasty stuff and burning your face off.

Franklin Sankar
01-04-2012, 05:28 AM
QUOTE...I would recommend twice just to get a really even heat before you put your starter bubble in.

Now I understand why they take so much time heating over and over again in the MOG videos. I used to think they just making up time until the show ends.
How did you discover this trick Scott?
Franklin

Scott Novota
01-04-2012, 09:37 AM
I am sure I asked the same question at some point a long time ago right here on this board. It would not surprise me if David was not that one to enlighten me.

Mark is where I was about 7 years ago so I can kind of read his mind because I had all the same questions when I first started up my own little shop to feed my need. On that note Mark fill free to shot me a Personal Message I would be more than happy to be a sounding board for you. The road you are on I have already run down at full tilt and slammed into many a brick wall head first. Maybe I can help you side step one or two.

Knowledge transfer is a wonderful thing here on this board. I just never expected to be on the other end of it. This is without a doubt the best resource on the internet for glass. So many people here with so many different paths to the same end. The aggregate knowledge and help that is freely passed around here is truely amazing. This does not happen everyday. On that note I need to send in my yearly donation for keeping this place alive.

Pete VanderLaan
01-04-2012, 03:03 PM
Knowledge transfer is a wonderful thing here on this board. I just never expected to be on the other end of it.
**************
That is what happened to me. As I persevered, I asked questions constantly but with time it got to where there were more people asking me questions and very few I could ask questions of. Now, Chuck Savoie and Mark Peiser are my occasional sounding boards on chemistry.

But I learn something new on Craftweb every single week. There are people who don't use it because of the dorky name. But It's Tink's Dorky name and she loves it and I would not consider ever changing this neat little thing that she sponsors so quietly with never a peep of complaint or a seeking of the limelite.

When we first got together she had ads on it. I told her I wouldn't run it if it had ads. She said it would cost her a good deal. She dumped the ads and never complained.

She's really remarkable. .

Franklin Sankar
01-04-2012, 07:59 PM
I knew This could not happen without an angel. Tell her thanks for me.
Franklin

Pete VanderLaan
01-05-2012, 03:42 AM
Q I am re-melting Spectrum glass and using it for blowing. Is there any danger from breathing the fumes?
A It depends on when you choose to breathe the fumes! During the re-heating process, at temperatures of 2450-2500F (required to re-melt our glass), there will be some measurable "gassing-off" of volatile materials. Commonly, this gas is directed from your furnace or melting chamber up and out a flue designed for this purpose. At these temperatures, if you hold your face over the flue (or the molten glass) and breathe deeply, you are in danger of both ingesting some nasty stuff and burning your face off.
***********
I am continually amazed at the things some people say. System 96 is a glass, and like any other glass will remelt not requiring any ridiculously high temperatures. I think Spectrum wants to sell all the glass it can here and if you reuse your scrap, they won't sell as much. While fluorine glasses can change a good deal on remelting, clear cullet doesn't much or what you get out of the bag wouldn't work either.

The basic product out of the bag indeed does gas off since it is not completely melted, so much so that the combined boron/barium gas creates a somewhat catalytic effect on your crucible and furnace- basically any of the silicate or fireclay components. The company used to blame the wear on the crucibles themselves but finally admitted that the glass was quite caustic. So they created premium nuggets which don't have the same issue but inexplicably in my mind, made the glass a 97.5 which they don't mention on the bags,

All glasses gas off to a degree but in micrograms per hour. Some are a lot worse than others.

As to melting over 2300F, Your elements would be wrecked if you go above 2275 for long but it's all way hotter than you need for system 96 anyways.

As to your collar problem, the clear in the collar has a completely different viscosity than the color for the most part. Try at least to keep the clear you use for the pickup at a dead minimum to keep from dropping it. Casing the color and evenly heating it is the only way you are going to get even distribution of the color as a first gather. The blowpipe is robbing the pickup color of heat and unless you can distribute the heating evenly ( through casing), you're gonna have trouble with it.