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Glaze Testing—Triaxial Blends—Dry/wet Mix Question


Saki

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Hi

 

I want to do a blend test. I measured out 1000g of the base glaze and mixed the dry materials in a bucket. I intend to separate this dry mix into 10 cups of 100g each and then add the colorant I am testing in 1% increments (1%-10%).

 

My question is this: is the dry mix sufficient? that is, can I separate the dry mix of the base glaze into the cups or do I need to add water first, do a wet mix, and then separate it into the 10 cups? The advantage of separating the dry mix is that it will be easier to weigh it out (100g to each cup). However, I am not sure if mixing dry materials will sufficiently mix the ingredients so that each cup will have the same base glaze?

 

On the other hand, I am not sure if a wet mix is much better because the glaze might not be evenly suspended and some materials might settle between pouring it into cups, which would also result in different base glazes in each cup.

 

Any thoughts or suggestions would be greatly appreciated.

 

S

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Partitioning a dry mix is risky.  There is a very high probability that the ratio of ingredients will be significantly different in each part.  The reason is that the solids are of different density and size and tend to segregate when pouring and handling.

 

I always mix the base glaze to the "right consistency" and then partition the batch into separate containers. To make it easier to know what is going on, I weigh the amount of water I add to the total batch to reach the "right consistency" for testing.  This gives me a water to solids ratio and the solids to total solids plus water ratio for the well mixed batch.   

 

After making the partition, I get the net weight of glaze in each container to check that I made the partition equal.  I use the ratio of solids to the total of solids and water weight to adjust the amounts of "stuff" to add to the individual batches. 

 

This sounds confusing and tedious, but it really just tedious. 

 

LT

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You attached an image of a triaxial blend, but it sounds like you are just doing a simple line blend?

 

You should really try "volumetric blending" popularized by Ian Currie.  You'll need to mix two wet batches of glazes of equal volume, one for each end of the line.

Ian's original article:

 

http://ian.currie.to/original/line_blend.htm

 

More on line/triaxial blends using a syringe:

 

http://glazy.org/help/blending#lineblends

 

In my experience, volumetric blending is really accurate as long as you are careful and don't try to make too many intermediate blends.

 

To answer your original question, dry mixing is only the first step before you wet mix and then sieve.  Neither dry mixing nor wet mixing are going to give you an evenly dispersed, consistent glaze.

 

I would suggest hanging on to your 1000g of dry mix glaze.  Completely start over using volumetric blending to mix two new glaze batches (that have been sieved) and fire the tests.  Using the most promising test, add the necessary ingredients to your original 1000g dry mix, then try it out on a bowl or cup.

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Partitioning a dry mix is risky.  There is a very high probability that the ratio of ingredients will be significantly different in each part.  The reason is that the solids are of different density and size and tend to segregate when pouring and handling.

 

I always mix the base glaze to the "right consistency" and then partition the batch into separate containers. To make it easier to know what is going on, I weigh the amount of water I add to the total batch to reach the "right consistency" for testing.  This gives me a water to solids ratio and the solids to total solids plus water ratio for the well mixed batch.   

 

After making the partition, I get the net weight of glaze in each container to check that I made the partition equal.  I use the ratio of solids to the total of solids and water weight to adjust the amounts of "stuff" to add to the individual batches. 

 

This sounds confusing and tedious, but it really just tedious. 

 

LT

Thank you so much for your detailed reply. Your explanation of your partitioning process is not confusing at all! Rather, it is very clear and enormously helpful. I will give this method a try.

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You attached an image of a triaxial blend, but it sounds like you are just doing a simple line blend?

 

You should really try "volumetric blending" popularized by Ian Currie.  You'll need to mix two wet batches of glazes of equal volume, one for each end of the line.

 

Ian's original article:

 

http://ian.currie.to/original/line_blend.htm

 

More on line/triaxial blends using a syringe:

 

http://glazy.org/help/blending#lineblends

 

In my experience, volumetric blending is really accurate as long as you are careful and don't try to make too many intermediate blends.

 

To answer your original question, dry mixing is only the first step before you wet mix and then sieve.  Neither dry mixing nor wet mixing are going to give you an evenly dispersed, consistent glaze.

 

I would suggest hanging on to your 1000g of dry mix glaze.  Completely start over using volumetric blending to mix two new glaze batches (that have been sieved) and fire the tests.  Using the most promising test, add the necessary ingredients to your original 1000g dry mix, then try it out on a bowl or cup.

Sorry, my initial post was unclear. I am doing a triaxial blend test. I don't think the Currie method will work for a triaxial blend, but it looks like a useful model, and I hope to try it in future glaze tests. Thank you!

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Volumetric blending works just as well for triaxials.  The link I mentioned (http://glazy.org/help/blending#lineblends) has this information further down the page.

 

If you are mixing a 1000g base glaze, separating it into smaller batches, and then further adding materials to each separated batch, you will need to mix and sieve each separate batch again to get accurate results.

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Volumetric blending works just as well for triaxials.  The link I mentioned (http://glazy.org/help/blending#lineblends) has this information further down the page.

 

If you are mixing a 1000g base glaze, separating it into smaller batches, and then further adding materials to each separated batch, you will need to mix and sieve each separate batch again to get accurate results.

Ah, sorry, I hadn't realized the link had so many examples, including triaxials. Thanks for the clarification. Great information! 

 

I already went ahead with my original batch, but the next time I do a line blend, I think I will give this method a shot. I'll just need to find the syringes. Thank you again!

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It did a slightly different method which I have explained several time on this forum. 15 marked 1-15 tiles and 4 metallic oxides/carbonates for 15 resulting combinations of color. 

Mix 250 grams dry base. Add water. put equal amounts into plastic cups which results in 50 grams. Label 1,2,3,4,5 add dry oxides to wet glaze in cups and sieve.

Add into 2,3,4,5  colorants ex. #2 cup might hold 3 % rutile which is 1.5 grams added to base. #3 might have  1% cobalt carbonate. #4 2% copper carb. #5 red iron oxide. You can use whatever colorant you want and try stains too.

The first row would have full strength colorants. 

Row I   1 base ,2,3,4,5

Row II 1+2, 1+3, 1+4 1+5  results would be 1/2 the percentage of the full strength

Row III  2+3, 2+4, 2+5

Row IV 3+4 3+5

Row V  4+5

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