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  #76  
Old 09-07-2017, 05:01 PM
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Pete VanderLaan Pete VanderLaan is offline
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I agree about the viscosity. We would melt cad sel reds at 1975F. You still get the dissolution of the pot though and the dissolution of the furnace. We never went above 2200F to fine and it took only two hours. You really need to know the guardrails on the road though and that's simply experience. Wash State OSHA certainly went after the fluorine people. Is it worse than Cadmium? good argument. Do you have young children? Better answer.
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  #77  
Old 09-07-2017, 06:41 PM
Dave Bross Dave Bross is offline
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Does a lower E&T require more or less heat? I'm going to PM my email for the worksheet right after posting.
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My best guess is the lower powered/lower temp melters volatize less of the things that raise expansion.

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Also, my intention in leaving out the STP was simply for flexibility down the road.
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Don't do that.

Hint - Look up the calcium content of bone ash or other phosphate sources then check that against the max allowed calcium in my old post in Antiques.

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I know how to add more but removing chemicals from batch sounds tricky
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This is why you need to learn how to batch then experiment with what does what.
Pete or I can hold your hand on that until you're up to speed ... or until someone is rolling our ashes into a pumpkin and it's too late.

Having the spreadsheet to play with will help you get a better grip on this also. Just play around with it and see what changing something does. With this caveat:

Always remember the two rules of eight.

1 - add up the percentages of the alkalais (stuff from 1st column of periodic table) and divide by eight. The number you get is the percentage of alumina you MUST HAVE as a minimum. Usually somewhere a bit over 2% for the expansions we're working with.

2 - you always want to have 8% or better modifiers (stuff from the second column of the periodic table). You can fudge this one a bit if you're using some zinc.

Looking back over my phosphate recipe I would just drop the borax due to furnace wear problems with borax, which makes a negligible change in the expansion. All that nitrate and lithium would ensure it went down fast at low temps. If you have a more powerful furnace with higher temp capabilities you could probably probably cut back on those two for economy. If I was mixing it for the general public (god forbid) I would leave all the lithium and nitrate in there to keep it more idiot proof and fast melting.

Also notice there is no antimony in that recipe.
It goes down so fast the big bubs are gone in about 4-5 hours. I used it with all the tiny bubs still there for added sparkle under clear. If you actually wanted to fine it you would need antimony and I haven't tried that so I don't know if any surprises might result. It's also very low viscosity so it may fine by itself if left to sit at melt temps. for a while. Everyone who has tried it likes it as-is without bothering with fining it.

Another good reason to mix this in custom batches is to play around with the phosphate percentage. The percentage I used is "middle of the road" in that it strikes gradually and can be re-struck until quite dense.
You can get some awesome veiled glasses going down slightly above 1% phosphorous, which is the point at which it begins to be an opacifier.
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Last edited by Dave Bross; 09-07-2017 at 06:48 PM.
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  #78  
Old 09-07-2017, 07:29 PM
Dan Vanantwerp Dan Vanantwerp is offline
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So, first off...if anyone has an affinity for coloring glass, Dave's instructions for the Glass calculator are a great read. Thanks so much for putting all that together. It's much more than just a user guide.

I've sent the original formula to East Bay to determine their interest in batching it. They sound amenable to doing whatever mixes you want as long as the ingredients are safe and well-characterized. However, I'm not wanting 1000lbs so I may be SOL.

My idea is a phosphate (minus the phosphate) pre-batch that contains everything else. Probably not the borax though. But, like STP, borax is another ingredient that would be easy to come by and added on my own if the results suggest it might help. That way I could modify the amount of phosphate and get from deep opaque to the veiled effects you mentioned. Also, the Penland Opal red asked for a small reduction in the phosphate added versus the other opal colors. Flexibility is what I'm hoping for...I like the idiot-proof comment also. Seems like a good way to achieve some initial success.

I will update with my dealings with East Bay. Thanks again.
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Old 09-08-2017, 12:50 AM
Andreea Virag Andreea Virag is offline
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Cristalica cullet info

Hello everyone,

Thank you first of all for considering even talking about our studio glass pieces. As each furnace and melting process can differ in its complexity, we invite you to mail us all your specific questions or contact us by phone anytime.
Pete knows our cullet very well, but we do recommend you trying out for yourselves to see if it's a good fit for your work. I believe it is as our clients worldwide have had great results with blowing and kiln casting as well.
See? Didn't mean to sound like a sales person, and here I am still writing an essay.
But don't believe me, let the quality of the glass "noodles" speak for itself. I am quite sure you'll be hooked.

In the States, you can get info on the glass and the cullet itself via our exclusive suppliers, Spruce Pine and Olympic Color Rods, and in Canada - our colleagues over at Kuta Glassworks.

For any questions, curiosities or just a talk about glass, feel free to get in touch!
Thanks, guys!
Have a great evening! (morning over here

Andreea Virag
Viel Spaß beim Glas!
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  #80  
Old 09-08-2017, 07:26 AM
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Pete VanderLaan Pete VanderLaan is offline
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this thread has entirely morphed from the original title and both directions are fine. I am inclined however to take the discussion aspect of phosphates etc into the board on color and to leave the issues with Cristalica and Spectrum as a standalone.
Is there any problem people have with that and if not, I'll start moving and shaping the comments so far.
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  #81  
Old 09-08-2017, 09:26 AM
Dave Bross Dave Bross is offline
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Pete,

Good idea on moving the phosphate parts of this to the color and batch dept.

Dan,

You still have to be able to figure what you're doing, pre-mixed batch or not. The sodium in STPP or whatever ride along components in other forms of phosphorous would have to be compensated for in some way without going beyond certain numbers with the pre-mixed.
It's also harder to take an expansion number down than up.

What E&T number do you have East Bay mix it to? Even if you did something like match it to SP on E&T numbers so it had a bigger market you still have to deal with the possibility of the strain points (where the glass sets up) being different enough to cause trouble on compatibility. To not have an embarrassing situation you should batch it and melt it yourself and test the compatibility before going commercial.

Having it pre-mixed also removes a lot of the possibilities for changing it to where you need it to be on all counts.

One thing I thought about but never tried is getting the phosphorous via phosphoric acid. It's easily available on Ebay and no other elements in there to watch out for. Somewhat more hazardous to deal with though.


This would be one of the easier glasses to mix, melt and test because not too many components.

1 - A trip to Home Depot or similar for a 5 gallon bucket, paint mixer (I suggest a plastic one, it's easier on the bucket) and grab a bag of hydrated lime. It may not be super clean lime but it will work for this because it's opaque glass.

2 - Everything else could be ordered in small quantities from a pottery supply, Ebay or US Pigment, and shipped to you. If you have a nearby pottery supply they will have most of it.
Try to find Short Mountain silica (pottery supplies for this), you might as well get a 50 pound bag and this stuff is super nice for all glasses.

3 - I like these guys for scales. Get one that does at least 15 pounds and will measure in pounds, more weight capacity is better.
http://www.oldwillknottscales.com/ca...ng-scales.html
I've been using an older 15 pound version of this forever. The only catch is it goes crazy if you try to use it too far below room temp so no outside batching in winter:
http://www.oldwillknottscales.com/my...traship35.html

4 - Get some cheap fireclay crucibles and figure a way to put them in your glory. Other ideas - Mark Wilson used to have a tiny glory with a shallow clay tray in the bottom to melt stuff in. He used the burner from a Turkey fryer to power it. - make a tiny gas color melter like all the guys on youtube building little forges and furnaces. a homemade burner and some kind of refractory and away you go.

Other than the melter, all this would fit in two or three big storage totes.
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  #82  
Old 09-08-2017, 01:59 PM
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Pete VanderLaan Pete VanderLaan is offline
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Dave, mix 20lbs of it for him. Charge 5 dollars a lb plus shipping. See if it works. If it doesn't, $100 dollars will seem really cheap.

I m not kidding at all. The cart is getting way too far in front of the horse at this point.
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