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How to measure out chemicals for glazing


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#1 1Artsygirl

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Posted 18 June 2012 - 02:53 AM

I am new at making my own glaze from scratch and I am confused in regard to the mathematics of percentages/grams of materials needed. (EXAMPLE of 2 "fake" glazes )..
EXAMPLE 1
10 percent ferro frit.
30 percent epk,
60 percent feldspar.
NOT A REAL RECIPE... ok so I get that I need to measure out each ingredient to make a total of 100 percent. Well what if I want to make 5 gallons of the glaze.. how to I compute it into gallons needed?? And on top of that what if the recipe calls for extra ingredient's after 100% of whats needed is computed.


EXAMPLE 2
10 grams ferro frit,
30 grams epk,
60 grams feldspar. Equaling 100.

Well 100 grams does not make very much at all. I need buckets. Obviously I will make the small amounts first so I can test tile everything but when I'm ready ( I'm past ready), I will need enough to do over 100 pots in various colors..etc..

In short, what if I want a 5 gallon bucket of the glaze. Maybe I should request for totals of a 1 gallon bucket. I can just do the ingredients x 5 to get 5 gallons. I do have a very nice triple beam scale that I got recently. I feel pretty stupid asking the community for the help but I have been looking for a week now on how to figure this out..no answers so here I am.
Kind regards and thank's for any input.
( I knowwwww that I'm not "stupid" , I'm just a middle aged gal who hasn't used her math skills since Jr College :)

#2 justanassembler

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Posted 18 June 2012 - 03:28 AM

To answer your first questions, most glazes are calculated @ 100% minus their colorants--so your ingredients will equal 100% not counting colorants which are usually listed last on a recipe and will be small percentages of the total of most glazes.

In terms of your question regarding wet quantities, a rough rule of thumb is that 5-7lbs of glaze materials dry makes roughly a gallon wet. This of course differs a lot depending on the consistency of the glaze you are mixing, you'll have to do some testing on your specific recipes, but thats a rough guideline.

#3 TJR

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Posted 18 June 2012 - 07:08 AM

I can only give you my experience, so don't shoot the messenger.
1. An ice cream pail will hold a 1000 grams of glaze with water.
2.An average plastic pail that you get from a baker with tight fitting lid will hold 6,000 grams plus water.
3.10,000 grams of glaze will fit in the larger plastic pails
4.A styrofoam coffee cup will hold 100 grams of glaze for testing, which you should do first.

All glazes should be mixed dry first, then added to water.[use a dust mask]. Glazes are then sieved using a 80 mesh sieve, then re-sieved using a 100 mesh sieve. Buy these at your pottery supply store.
TJR

#4 Mark C.

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Posted 18 June 2012 - 09:57 AM


EXAMPLE 1
1000,Grams ferro frit.
3000,Grams epk,
6000,Grams feldspar.


EXAMPLE 2
1000.oo grams ferro frit,
3000.00 grams epk,
6000.00 grams feldspar. Equaling 10,000

I fixed these so they will make a little less than a 5 gallon bucket.

You can move the decimal or multiply them by whatever number you need.
Most of my glazes are 7.000-10,000 grams
I fill a bucket about 1/2 full or more then add the dry materials as I weight them-then power mix them and sieve them into the final bucket thru an 80 mesh.
Then add water slowly as I adjust them with a hydrometer.
I mix glaze about 1/4 of a day every two weeks
Mark
Mark Cortright
www.liscomhillpottery.com

#5 Marcia Selsor

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Posted 18 June 2012 - 02:52 PM

Mark gives some good advice. five gallon make 7,000-10,000 depending on the density of the ingredients. Some chemicals are denser and occupy less space...fitting into a five gallon bucket easier than a glaze of less dense material like ash or magnesium carbonate.
maybe mix a batch of 1,000 grams and see if it fits into a half gallon container.
Marcia

#6 clay lover

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Posted 18 June 2012 - 10:50 PM

Have you tested a small amount of this glaze to see if it suits you and your clay before investing in a large amount? A 5 gallon bucket of a glaze can be a significant amount of something you find out you don't like.

#7 1Artsygirl

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Posted 24 June 2012 - 04:28 AM

Thank you all who have written me. In answer to my own question, So hers exactly what my problem is..In general... a recipe calls for percentages and I need to calculate the ingredients into grams. so changing percentage into grams. Is there a easy sure fire way to figure this every time? Man I feel not so smart..

Ok a new question is this....I have tested with small amounts of a transparent glaze with mason stains added. I had also bought a premixed ..powder.. Laguna birch white glaze that I plan on adding Mason stains to it also. With what I'm reading, 10% of a mason stain is what I need when mixing for colors added. Does anyone know if it's possible to add other dry ingredients to a premixed glaze? The birch white is Laguna WC-511 cone 5 glaze. Say I wanted a sea foam green...any suggestions kind regards, Penny

#8 atanzey

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Posted 24 June 2012 - 06:25 AM

The 'way' to calculate is to convert your percentage to a decimal and multiply by the total amount of glaze that you want to make. For instance, say you need 20% Ferro Frit and you're making a 1000 gram batch.

0.20 X 1000 = 200g

You have to do this every time, unless you always make the same size batches, and write it down for that size.

OR, if you have a spreadsheet program, you can automate it. Then you can set it up so that you change the batch size and it calculates for you. I attempted to attach a simplified copy of mine in Excel, but it didn't seem to 'take'.

Alice

#9 Marcia Selsor

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Posted 24 June 2012 - 07:44 AM

Thank you all who have written me. In answer to my own question, So hers exactly what my problem is..In general... a recipe calls for percentages and I need to calculate the ingredients into grams. so changing percentage into grams. Is there a easy sure fire way to figure this every time? Man I feel not so smart..

Ok a new question is this....I have tested with small amounts of a transparent glaze with mason stains added. I had also bought a premixed ..powder.. Laguna birch white glaze that I plan on adding Mason stains to it also. With what I'm reading, 10% of a mason stain is what I need when mixing for colors added. Does anyone know if it's possible to add other dry ingredients to a premixed glaze? The birch white is Laguna WC-511 cone 5 glaze. Say I wanted a sea foam green...any suggestions kind regards, Penny

yes you can add colorants to a clear glaze. For a pale sea green you could look at mason stains or try a little copper carbonate 1-3% for a start. Raw metal oxides can have different color effects depending on the base chemicals in the glazes...if it is alkaline or potash. Mason stains have reference codes which indicate what stains work with what chemicals , temperature limits etc.
http://www.bing.com/...Chart&FORM=IGRE
Marcia

#10 neilestrick

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Posted 25 June 2012 - 03:09 PM

My rule of thumb is that a glaze will fit 10,000 grams in a bucket only if the clay content is below 10%. At 10-12% I drop down to 9500 grams. At 13-16% 9000 grams. More clay than that I go to 8500 grams per 5 gallon bucket. Other ingredients will affect this, but clay has the greatest affect on how much water is needed in a glaze. More clay equals more water equals smaller batch.

Colorants are added in addition to the 100%. If you need 9% red iron oxide in a 9000 gram batch, you need 810 grams of iron in addition to the base glaze. Large quantities of colorants, such as 9% iron, will also require that you reduce the batch size.
Neil Estrick
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Owner, Neil Estrick Gallery, LLC
www.neilestrickgallery.com

neil@neilestrickgallery.com

#11 1Artsygirl

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Posted 30 June 2012 - 03:03 PM

Thank you again to all who have written me. I think I have it down pretty good now. Kind regards, Penny




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