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Old 12-20-2016, 08:47 PM
Dave Bross Dave Bross is offline
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Lists of Color Additives for Batch

The picture attached was a handout used at Penland. You will probably need to download it and expand it a bit in whatever you look at photos in to read it. I had to shrink it big time to get it to fit here. I always thought it was Dudley's but he says it isn't.
The list below is from Penland too.

With any formulas like this it's best to just extract the coloring oxide percentages and try those in whatever batch you're working with. That's best done with the old trick phrase for percentages, target over total times 100. Target would be the coloring oxide you're working with divided by the total of all the batch ingredients. Then multiply what you get by 100 (or just move the decimal point two places).

Keep in mind which glasses want oxygen to show color and which don't.

Manganese wants oxygen to show purple - add a pinch of potassium bichromate to ensure it has enough - 3-5% potassium in the batch will radically improve the purple color. It's brownish without it.
many silver and all copper ruby glasses want reduction - best accomplished with black tin
phosphates have so much oxygen in them you can forget reducing colors in them.

Most of the coloring chemicals can be had from US pigments:

https://uspigment.com/product-category/chemicals/



Penland Additive Formulas for 19 pounds of batch. (I think this may be wrong, seems like an awful lot of colorant for 20# of batch on some of these)

Purple: 200g mang dioxide, 90g soda ash.

Opal Purple: 70g mang dioxide, 15g cobalt carb, 450g bone ash, 95g soda ash.

Violet: 150g mang dioxide, 5 10g cobalt carb, 65g soda ash.

Opal Yellow: 110g cadmium sulfide, 20g sulfer, 650g zinc oxide, 70g. pot ash, 90g
soda ash.


Yellow: 128g cadmium sulfide, 660g zinc oxide, 68g pot ash, 95g soda ash.

Yellow Orange (for 18lbs): 40g selenium, 650g zinc oxide, 110g cadmium sulfide,
140g pot ash.


Opal Green: 50g potassium dichromate, 20g black copper oxide, 450g bone ash,
85g soda ash.


Opal Green 2: 25g potassium dichromate, 10g black copper oxide, 90g borax.

Opal Jade: 40g black copper oxide, 20g potassium dichromate, 450gbone ash, 95g
soda ash.


Turquoise: 200g copper carb, 55g potassium dichromate, 95g soda ash.

Blue: 200g copper carb, 7g cobalt carb, 25g potassium dichromate, 90g soda ash.

Med Dark Blue: 150g black copper oxide, 90g soda ash.

Opal Dark Copper Blue: 240g black copper oxide, 405g bone ash, 90g soda ash.

Lapis: 50g cobalt carb, 180g borax.

Opal Lapis: 30g cobalt carb, 10g black copper carb, 450 bone ash, 85g soda ash.

Opal Red: 128g cadmium sulfide, 64g powdered selenium, 600g zinc oxide, 68g pot
ash. 430g bone ash, 430g bone ash, 95g soda ash. To darken, add 72g selenium,

90g pot ash.


Pink (18lbs): 40g selenium, 90g cadmium sulfide, 600g zinc oxide, 68g pot ash, 80g
soda ash.

Black: 231 mang dioxide, 11g potassium dichromate, 32g cobalt carb, 118g black
nickel oxide.
Attached Images
File Type: jpg DudleyColor resize.jpg (82.7 KB, 28 views)
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Last edited by Dave Bross; 12-21-2016 at 03:26 PM.
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Old 12-20-2016, 10:18 PM
Eben Horton Eben Horton is offline
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Time to build a mini color pot!! Thanks for sharing this.
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Old 12-21-2016, 07:43 AM
Kenny Pieper Kenny Pieper is offline
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Keep in mind that those formulas are for adding to spruce pine batch color base which starts out with less soda than the regular 87 formula.
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Old 12-21-2016, 08:25 AM
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Pete VanderLaan Pete VanderLaan is offline
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I'm not sure of that Kenny. The color base was notable back when Tom and I talked about doing it that it would not have either the antimony or the nitrates. Probably tom used Sodium Nitrate if you are indeed correct but it would have been about 120 grams in a fifty lb bag, no more. It is the case that most colorants result in your needing to add soda (or whatever alkaline flux you choose) to some degree. It varies every time.
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Old 12-21-2016, 08:29 AM
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Pete VanderLaan Pete VanderLaan is offline
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Some of this doesn't really make sense.

" Opal Red: 128g cadmium sulfide, 64g powdered selenium, 600g zinc oxide, 68g potash. 430g bone ash, 430g bone ash, 95g soda ash. To darken, add 72g selenium,... and apparently all that goes in 19lbs of batch? wow!

You really have to read these carefully.

I think quite a few of these were from the days of Bone Ash 21 which is long gone as an interesting additive. Mark said he still had a bag in his basement and I think Dudley told me the same thing recently. Really difficult to melt well. I would substitute STP .
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Old 12-21-2016, 03:05 PM
Dave Bross Dave Bross is offline
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I never tried the ones under penland additive formulas. I just picked that up sonewhere and never did anything with it.

I've done a lot of the ones on the sheet that's a picture (extracting the coloring oxide percentages) and gotten good results. If my memory is correct, if you melt them as stated you'll end up with expansion over 100. I used those percentages in the phosphates I melted, omitting the bone ash and just using the colorant percentages. They make VERY nice colors.
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Old 12-21-2016, 04:15 PM
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Most of those opals again call for bone ash 21 which was the real deal, a greasy bone ash immortalized by Robert Held at the 1968 NCECA Conference. It drifted around Penland for some years and gradually slipped into the sunset as there was this on weird truckload and no more. It came originally from Standard Ceramic Supply. It needed real heat to get it to not form Aphetite crystals as bi as your head.
Dudley apparently has a rather large stash of it but you would have to buy the whole thing. It was a lot, as in drums. I'll ask about it again since he approached me to help dispose of it at a tidy profit. I wouldn't recommend it. I think STP ( sodium tri polyphosphate) works better. What makes Dave's opal work so well is the strontium replacing calcium
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Old 12-22-2016, 11:32 AM
Kenny Pieper Kenny Pieper is offline
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Quote:
Originally Posted by Pete VanderLaan View Post
I'm not sure of that Kenny. The color base was notable back when Tom and I talked about doing it that it would not have either the antimony or the nitrates. Probably tom used Sodium Nitrate if you are indeed correct but it would have been about 120 grams in a fifty lb bag, no more. It is the case that most colorants result in your needing to add soda (or whatever alkaline flux you choose) to some degree. It varies every time.
Yep it is the soda nitrate that I refer to.
It is the subtraction of 1.7lb. sodium nitrate from 98lb. of batch.
The antimony is inconsequential except for the fact that its absence can make some of the colors harder to fine out.

After looking at some of the formulas more closely I can see that many of them have the addition of soda ash to correct for the subtraction of the soda nitrate
.

Last edited by Kenny Pieper; 12-22-2016 at 11:36 AM.
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Old 12-22-2016, 02:54 PM
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Pete VanderLaan Pete VanderLaan is offline
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I had been under the impression that Tom replaced a good deal of that sodium with sodium Carbonate and you're giving me information I did not have. I did not know it was that much. Those two formulas would be quite incompatible with the total omission. The point was to get the nitrates out, not the sodium. Antimony can act as both a reducing agent and an oxidizing agent, sometimes dropping to Sb2O and sometimes going up from Sb203 to Sb205

And again, it has to be mixed when you get it. We did make a copper ruby with it the first try when Tom came and took the class way back when in Santa Fe. That even surprised me.
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