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Old 05-29-2012, 02:08 PM
Doug Sheridan
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Spectrum Premium Nuggets: Corrosive or not?

It seems that Spruce Pine will not have their cullet furnace hot for a few months, and I've not heard or read about the premium nuggets for some time. Did they work out the 97.5 issue, and does it eat furnaces like the regular nuggets?
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Old 05-29-2012, 02:59 PM
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After using about 3000lbs of the spectrum 96 old nuggets it did one hell of a job on my furnace. Basically a full rebuild from the ground up.

I switched furnaces at this point and started using the new nuggets and had gone though about 4000lbs of the new nuggets with no real problems at all in the new furnace. Normal wear and tear no visible problems like the old nuggets at all. I had 1000lbs of the old nuggets left and did not want to waste them. This was a huge mistake. They did 3 times more damage in 1 month than the whole previous 4000lbs of new nuggets over a year period.

In short, and only based on my limited experience, is that the new nuggets do not do the damage to the furnace the way the old nuggets did. I just ordered anouther 4k of the new ones and will never ever go back to the old ones.

Take anything I say with a grain of salt as it is only from my personal experience.
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Old 05-29-2012, 03:23 PM
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I just wish they would make premium nuggets compatible. I make a line a production dicro implosion paper weights and after two days of losing 60 to 70 weights I gave up. The premium isn't even compatible with the system 96. I know because the dicro I use is all coated on system 96.

I have never had a problem in blown ware but then again I don't make thick chunky stuff. I would still like them to revist the comparability issues.
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Old 05-29-2012, 06:54 PM
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I'm with Scott on the corrosion question. I switched to SPectrum Premium in January this year and have not had any corrosion issues since switching over. I haven't had any compatability problems either but I don't do heavy weights like Sky so I can't really say. There is another recent thread about this somewhere here and I believe the corrosion issues with the other SPectrum nuggets was due to borax.....right Pete?

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Old 05-29-2012, 09:35 PM
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Hey Doug:
Did SP give any indication on when they will be hot and producing again? Have they even started building the furnace? They told me in Jan that they would be up and running in June/July....
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Old 05-30-2012, 06:15 AM
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The Steel work is done, courtesy of great work from Lawrence Duckworth. Charlie is finalizing the AZS liner stuff, which is the slow part. I think we'll see glass by Christmas. I would be surprised if it can be faster than that. It's quite the beast.

My belief about the borax which, keep in mind is a mix of sodium and boron, is that is that it becomes a dissolving catalyst when combined with barium in any glass. I cannot prove that but I've seen glasses that contain both before and they have all had this problem. I believe the nuggets are very close in formulation to the early Crystallica glasses that came out of Europe. Barium really loosens a glass up but most people use it for brightness. Couple that up with the effect that Borax has of both softening while maintaining Linear expansion pretty much and you have a material that is very fluid and can really get into the spaces between the tabular alumina grains in the pot. Frank Wooley used to say to me that no one glass is more corrosive than any other and that it was just a question of viscosity at any fixed temperature but this stuff seems to prove that generalization incorrect since the stuff seems to attack everything made of silica, alumina or fireclays. It reminds me of my fluorine melts is its aggression. SP87 does not contain borax but it does have barium and it is simply not reactive with furnace parts in such an aggressive way.

What seems to me (and I'm making an educated guess again,) makes the spectrum nuggets so corrosive is that they haven't actually completed the chemical reaction from being melted. They are still gassing off. So, when they get put in an electric furnace with no vents the furnaces , it's a recipe for dissolution. At the very least the furnaces need to be vented and none of the electrics were designed that way. Comparatively, electric furnaces are a fairly recent step in evolution and it just wasn't anticipated as a problem.

I recently rebuilt the door on mine and installed a vent and it's remarkable how much crap comes out of that hole in the form of yellow crystalline stuff. I plug the hole when I'm not charging. My glass formulation does have Borax in it although very little, 1.65 lbs in a 78 lb mix but it contains no barium. I don't have trouble with it beyond the pot slowly dissolving which is a cost of doing business.
Where are we going and why am I in this basket?
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