How do I convert % to grams in a glaze formula? Is there a online conversion chart where I can just plug in the numbers and voila!

Mathematically challenged,

Acg

Started by acg, Mar 11 2014 05:02 PM

6 replies to this topic

Posted 11 March 2014 - 05:02 PM

How do I convert % to grams in a glaze formula? Is there a online conversion chart where I can just plug in the numbers and voila!

Mathematically challenged,

Acg

Posted 11 March 2014 - 05:17 PM

Most recipes are written at 100 grams or close to it. it is a straight conversion. Increasing the weight for the size of your container is approximately multiplying anywhere from 500/ gallon to 1000 grams per gallon depending on the density of the chemicals being weighed. A light fluffy chemical like ash or magnesium will take more space so that would be closer to 500 grams per gallon. Dense materials like Frits would have more weight per gallon. So underestimate so you don't overflow your container until you are fMiliar with your recipes.

Marcia

Marcia

Marcia Selsor

http://www.marciaselsorstudio.com

Professor Emerita Montana State University-Billings

Posted 11 March 2014 - 06:00 PM

Yep, if your recipe isn't normalized to 100, do so. Once you do this, SI is already base 10, so you'll have a 100 gram recipe which you can then multiply to your desired batch size.

You did ask how to convert from %, so the recipes would already be normalized to 100, but if not:

In order to normalize a recipe, ignore the unit or measurement, and total the amounts of all ingredients in the recipe (ignore colorants as these are applied outside of the base recipe). Divide each ingredient by the sum of all ingredients to determine what percent of the recipe each ingredient makes up. Multiply each of these decimals by 100. For example:

Flint 30

Gerstley Borate 25

Whiting 20

EPK 30

Soda Ash 10

total amount: 115

Flint 30/115*100= 26.09

Gerstley Borate 25/115*100= 21.74

Whiting 20/115*100= 17.39

EPK 30/115*100= 26.09

Soda Ash 10/115*100= 8.69

recipe total: 100.00

Take note this recipe is made up and is not a formulated glaze.

Good luck!

Posted 11 March 2014 - 08:11 PM

If you have glaze formulation software like Hyperglaze or others, you can put a recipe in and it will convert it to percentages, and whatever size batch you want. Most cone 6 recipes will take 8,000-9,000 grams to fill a 5 gallon bucket. Cone 10 recipes can often go as high as 10,000 grams due to their lower clay content.

Neil Estrick

Kiln Repair Tech

L&L Kilns Distributor

Owner, Neil Estrick Gallery, LLC

www.neilestrickgallery.com

neil@neilestrickgallery.com

Posted 11 March 2014 - 08:27 PM

You said your recipe is already in %, which means it adds to 100%. By convention, most recipes present the base materials as adding to 100% with the colorants (usually metal oxides or stains), opacifiers (typically zircopax or tin oxide), and suspenders (e.g., bentonite, CMC, or Veegum) as additions. Thus the grand total of the numbers may add to more than 100%. Rarely, you might find a recipe where everything, including the additives, are calculated to total 100%. That's okay as the proportions of all the materials within the recipe are still balanced relative to each other.

To make a batch recipe, simply forget that it is percentages and think of them as just numbers. Then you can treat each number as any unit of weight you want to use - grams, pounds, tons, doesn't matter so long as you use the same unit for the whole batch. If you use the numbers as is, you might have a 100 gram batch, a 100 pound batch, or a 100 ton batch (though that would be a pretty big batch...). If you need your batch to be a different size, simply multiply every number by the same multiplier.

So now we have taken care of the theoretical, let's get practical. A 100+/- gram batch makes about 1/2 cup of glaze (making a huge presumption now that you are USA or UK-based and imperial pounds/gallons are your usual frame of reference...) or enough for a small piece or test. A 1000 gram batch makes enough for a 1.5 gallon ice cream tub, so multiply all the numbers in the recipe by 10. A 5000 gram batch will make about a half-full five-gallon bucket of glaze, for which you would multiply all the numbers by 50. A "mathematical safety" hint - after you have multiplied each number by 50 (or whatever), add add up all the new multiplied numbers to make sure they now add up to 5000. Don't ask how I know how easy it is to multiply just one of the numbers wrong or write it down wrong and now the batch adds to 4,373 or 9,747 or something silly ;-) (and if actually mixed that way would probably fail in the firing).

Posted 11 March 2014 - 08:30 PM

To go from percentage to batch, first convert the percentage to a decimal. To do that, divide the percentage by 100, or just move the decimal point two places to the left. For example:

10% becomes .10

30% becomes .30

2% becomes .02

8.4% becomes .084

0.5% becomes .005

Then multiply that number by the batch size. Using the numbers above in a 9,000 gram batch:

.10 x 9000 = 900

.30 x 9000 = 2700

.02 x 9000 = 180

.084 x 9000 = 756

.005 x 9000 = 45

Kiln Repair Tech

L&L Kilns Distributor

Owner, Neil Estrick Gallery, LLC

www.neilestrickgallery.com

neil@neilestrickgallery.com

Posted 12 March 2014 - 10:38 PM

Thanks everyone!

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