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Old 10-11-2018, 10:19 AM
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Pete VanderLaan Pete VanderLaan is offline
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SP Snowflake

So, I received one ton of my formula in the snowflake form last week. It is indeed a powder instead of pellets. Two years back, Spruce Pine mixed up a ton of the stuff as a regular pelletized version. I fought big lumpy bags for all that time. Pelletized, it was always a challenge to get colorants into melts evenly.

I wanted to see how the snowflake stacked up against the regular both in the time between charges as well as the quality of the finished glass. This was not done as a cool melt but was done starting at 2250F.

The amount of time between charges in an 80 lb pot was notable. It went about 20 percent faster with the snowflake. I ran the pot of glass overnight at about 2280F after the last charge went on. This worked to a perfectly fine glass the next morning, and was again far better in quality than the pelletized format. There's not a cord to be found in it and virtually no bubbles. Spruce Pine mixed it better than I could in my own shop.

It's far easier for me to load into the pot using a big plastic scoop. We put about 15 lbs in each charge. The pot is about 9 months old. It looks brand new since the formula is very kind to refractories with no Borax and only a tiny amount of fluorine. As to the dusting , yes, there is some but it's less dusty than when I mix in the batch room here.

I think the snowflake will be an excellent alternative for the wire melters but they will have to turn their furnaces up to 2250F.
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Old 10-11-2018, 11:48 AM
Josh Bernbaum Josh Bernbaum is offline
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I've almost exclusively melted SP pelletized in my 200# moly here over the last 8 years, and I love the furnace for the most part but it is a bit underpowered when it comes to melting batch as far as temp recovery times. But it has been noticeable, when I occasionally get bags from SP that happen to be more "powdery" and less pelletized, that my melt/recovery times do decrease. I may try just the snowflake next time.
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Old 10-11-2018, 12:24 PM
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we had an interesting accident over here when Eric was going to make some color using the pelletized stuff. He took it and ran it through a very coarse screen and only used the finer stuff to try to add the oxides. The resulting glass was profoundly stony and cordy. I mean lots of stones.

What it implied to me was that in the wetting process, the water doesn't really agglomerate to the batch evenly. The evidence suggested that it grabbed onto the silica first and later was taken up by other batch attracted to the pellet. It could possibly be the feldspar though. It certainly didn't suggest that all pellets are the same.

Now this was in my formula, not in Spruce Pine but I am assuming that the phenomenon is consistent which I find troubling. I had Eric remix, this time not screening down to the finer pellets and the resultant melt was just fine, all out of the same bag.

Normally in one ton of batch SP adds 10 gallons of water, for mine, they added 8 gallons. Too much or too little causes the conveyor to be uncooperative.

So I regard the pelletizing with some built in suspicions. If I recall correctly from the time I was down there visiting Tom and Harvey, the gooey batch got pushed through a screen to make the pellets and then air dried. I do think that there is a tendency for the larger pellets to have a fair amount of air trapped in them which really slows the melt time.
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Old 10-11-2018, 01:21 PM
Eben Horton Eben Horton is offline
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Is there a cost difference between pellitized and snowflake?
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Old 10-11-2018, 01:41 PM
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For SP87 I don't know. Mine was indeed more expensive at .91 lb but it has a lot of potassium in it for luster. The shipping was pricey as well, running 20 cents a pound. I think it came by boat across Lake North Carolina.
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Old 10-11-2018, 04:43 PM
Eben Horton Eben Horton is offline
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Still cheaper than cullet. But I loose a day to charging batch when I could easily top off every couple of days at the end of the day. Hmmm
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Old 10-11-2018, 06:22 PM
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well, if you had it to charge.
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Old 10-11-2018, 07:48 PM
Art Freas Art Freas is offline
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Quote:
Originally Posted by Eben Horton View Post
Still cheaper than cullet. But I loose a day to charging batch when I could easily top off every couple of days at the end of the day. Hmmm
Not really. At .91 + .20 per pound raw and given 20% loss due to outgassing it gives you about a $1.39 per pound final cost.
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Old 10-12-2018, 08:50 AM
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Well, for starters Spruce Pine is more like .72 lb. Mine is more expensive because it has expensive ingredients.

Outgas is not a constant. It's a measurement of the amount of CO2 mostly in the actual batch which will be lost to volition. Spruce Pine runs around 15-17%, not 20%. Mine is lower. It would be the case that cullet ( cut lets!) have less loss since the chemical decomposition is not complete but extract their pound of flesh in other ways like thermal shock, general lower quality, shorter working time, and of course, availability.

I'm pushing the notion of snowflake because of the wire melt people needing an alternative to unavailable cullet.

The demand for low melt characteristics in studio glass are not a free lunch. All that Boron coupled to barium play hell on the tooling. SP has no borax in it, nor does mine. When I look at my crucibles after nine months, they look brand new.

This of course fails to mention the higher luster and resistance to devit in my glass, something important to me.
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Old 10-12-2018, 05:30 PM
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Pete,

Can I get my hands on this?
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Old 10-12-2018, 05:37 PM
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Pete VanderLaan Pete VanderLaan is offline
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Indeed you can.

You have to specify it as an SP87 or a PWV . I have made a push to see it in Portland at High Temp. You could get my formula, or the SP Formula. I do NOT have a financial interest in this. If you bought my formula, I would get a royalty and it indeed is hand in glove with SP87 as to expansion. It is also a "fatter Glass" which is something Potassium does and I happen to like that. Stemware people might not.

My effort here was to offer up an alternative during a cullet shortage which I doubt will go away. No more, no less.

There isn't an "Isotoner Glass" out there.
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Old 10-16-2018, 11:09 PM
Hugh Jenkins Hugh Jenkins is offline
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So what is the identifiable difference in the "snowflake" as opposed to batch or agglomerated? This is not a glass format I have heard of before. Curious but most likely not going to buy any more for my own use.
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Old 10-17-2018, 09:31 AM
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Tom has done snowflake for a long time. The normal way the batch is processed adds about ten gallons of water to one ton of batch and then as I recall, gets pressed through a screen, then air dried and bagged.

The snowflake has 8 gallons of water which does not allow the batch to agglomerate in the same way the normal stuff does. It goes on a different conveyor to be bagged. It is very fine, approaching a raw mix but is less dusty.

The thinking for the wire melters is that it is a potential way for them to get glass during the celestial shortage of cut lets. The bigger chunks do seem to trap a lot of air and this doesn't . If people complain that SP87 is too dusty, they probably really won't like this stuff. Candy asses.

I find in my furnace that the snowflake melts a good deal faster that the big chunks. It's also better mix than what I do here at home. Again, I had it done with my formula which has a lot of potassium in it and seems very sensitive to becoming a brick like structure when using the full amount of water.

I bought a ton and that will last me a long time as I still do my unoxidized color glasses in house.

But I like it. I think High Temp may start stocking it in Portland.
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