glaze flakes off bisqueware before firing

[Rita Mattson]

hello,

I'm a new potter who plans to make my own glazes following recipes I find online.  I'm firing them in my home studio at cone 6 in my electric kiln.

I love the Wright's Water Base Blue glaze I found in one of the Ceramics Art issues, but have trouble making this glaze adhere to the bisque piece before firing.  I have not had this problem with any of the other glazes I have made.  Here is the recipe I followed:

Copper carbonate 5%

Lithium carbonate 3%

Strontium carbonate 9%

Frit 3110 59%

Edgar Plastic Kaolin  12%

Flint 17%

Add: Bentonite 2%

Is there anything you can suggest I add to this already mixed glaze (I made up a large batch!).

Someone suggested coating my pieces with karo syrup to help it adhere, but didn't work.  I've tried the brushing medium, but again no success.  Would appreciate any advise on salvaging this glaze, and in addition, what is wrong with this recipe.

thank you,

Rita

[Norm Stuart]

The price of Bentone-EW is comparable at $11.50 for one pound, compared with Axner's price of $11.79 for VeeGum, or $10.99 for Macaloid.  But since this had to be shipped from Texas, rather than being included with our regular truck delivery from Laguna, there was an extra  $9.11 for shipping.

Low quality bentonite costs something like $1.50 a pound.  We have a very old 50 pound bag from when our studio was at a different location - and I don't really know what to do with it.  Suspending glazes with it changes their look significantly.  Most low-quality bentonite is used as a component of drilling mud, or used for sealing reservoirs.

Nadine Mercader said:

Norm, How does the Bentone W compare in price to bentonite?


Norm Stuart said:

Juli -- The sediments at the bottom of glaze buckets are an essential part of the glaze.  With Cone 6 glazes this sediment in primarily the frit (the ground glass which makes the other ingredients melt properly).

If your glaze doesn't have enough clay, I definitely recommend Bentone-EW which I bought from Trinity Ceramics in Texas. US Pigment will be stocking this item soon, and may already have it.  If a glaze requires 1.5% bentonite to suspend, you use only 0.1% Bentone-EW and it mixes well just adding it to the glaze or water - quite unlike common bentonite.

[Nadine Mercader]

Thank you Norm, I have not been happy with the bentonite that I have, I will ditch it and try the Bentone EW.