New Glazes Tiles

Doing glaze tests is a tedious thing....

I can see why people find one or two glazes they like and just do everything with those.

But that would be too easy......


Testing glazes means a lot of stirring, sieving, dipping, drying, labeling, shifting buckets around, making notations on my test record pages.

Some tests were about new glazes; some were just checking old ones that might have changed over time.

I used to make my tiles really small because I put a string through the hole in the top and tie the tile to the glaze bucket. If the glaze is in a jar, I fasten the tile to the side with a big piece of transparent package tape.

I also use a Sharpie to label the bucket or jar in big letters. Saves a lot of time when you're trying to hunt down a glaze.

Bigger tiles mean more room for notes. I use any underglaze to do this. Just a dot on a piece of paper or spare yogurt lid is fine and handy for the underglaze. I also like the fine limner brushes to do the lettering with.

So, I'm rather sloppy when it comes to making these. Speed is the thing here, not perfection......

----------Of course, just as soon as I wrote this and fired the kiln, the thing overfired. The thermocouple failed. Pots welded themselves to the shelves and the witness cones are beautiful,  pearly puddles. 

A trip to Clay Art Center is in order. New shelves, new thermocouple, and while I'm at it, some grinding stones. 

Pottery:  It teaches you how to deal with failure and move on.

ALL the time.

Being Loose

Sometimes, when it doesn't count, when there's no pressure, when it's "Let's just see what happens"....... wonderful things can happen.

That's just what happened with this little trivet.

I was busy teaching myself how to throw an upside-down trivet.

I made essentially a bowl with an exaggerated bottom that was thicker than usual. I extended bottom rim and brought up the sides and turned the top edge outward, making a convex shape.

I let it sit on the batt until it was dry enough to take off. I turned it over, trimmed the (now) top to recess the surface and create a slightly higher rolled edge.

Then I cut into the sides of the bowl to make 4 feet, rolled worms to support them and let the whole thing dry.

It warped slightly during the bisque firing, but I kept it for a test piece anyway.

I dipped it in white glaze, dipped a big brush into watered down cobalt stain and just let the brush dance. I was thinking Sandy Brown. http://www.sandybrownarts.com/sandybrownarts.htm

During the firing, the stain went nuts. It popped all over the place making a lightly dotted patterns all over the white glaze.

Lessons learned.

Give a piece strong enough legs so it won't warp in the bisque firing.

Don't use straight cobalt stain.

It's possible to throw a trivet upside down with little trimming and alteration.

Big brushes and a fast and loose application makes a piece that comes alive.

Record Keeping

I have an old 3-ring binder standing on a music stand in my studio. A pencil is tied to the stand with a string. (I can NEVER find a pencil or pen when I need it.)

The binder is divided in sections and one section says, Glaze Record. Another says, Firing Record. A third says Throwing Record (although handbuilt pieces are included).

I make blank pages for these sections so they are already formatted for my notes.

Here's what a sample looks like filled in:

The last page, the firing page, has a check-off box for the type of firing, a place to note the program number on the computer and one for noting how long the firing took. (Kilns change over time and you need to know about any changes in firing.)

The box in the corner is for quick notes on this firing I want to remember. The space at the bottom of the page is for more elaboration. This makes it easy to flip back through the pages and find what I'm looking for if I need to review a past firing.

The Throwing page is really just a blank grouping of sheets available for me to note down the measured diameter of a teapot lid, the beginning raw clay measurements of a piece so I can know the shrinkage rate, a place to diagram something--whatever you Think you'll remember, but Know you won't.

I find this works for me and I keep scanned copies of these pages in a file on my computer to print new ones quickly when I need them.

Test Tiles and Stamps

I'm in the process of making a lot of small test tiles for some new glazes.

I've just rolled out 1/4 inch thick, 1 inch by 3 inch tiles for drying.

These are previous test stamps.

I was doing just indentations across the bottom of the tiles to check for pooling and breaks, but when I looked at my great collection of stamps and these, I thought, "Why not use stamps on the new test tiles?".

Glaze Tests

I tried out some new Coyote glazes in the last firing.

I don't worry too much about how perfect my test tiles look.....They are cut out of trash clay with a hole punched in the top so I can string them onto a twist-tab loop. I turn up the bottoms to see how the glaze pools and lay a bamboo skewer over the lower part to see how the glaze breaks. Sometimes these little tiles get tied to the bail handle of the big glaze bucket for quick reference.

Five new glazes with extended combinations were tried. I marked the tiles with underglaze abbreviations, then went back after the firing and labeled them with a fine-point Sharpie. Also made note of the glaze that shouldn't be used with food vessels.

I also tested some little bowls to see how the glaze behaved on vertical surfaces.

As with most of these kinds of tests, there were a lot of things that just didn't work out. But there were also some intriguing results.

It's also a bit of a chore to photograph the glazes, process the pictures through a computer program and adjust the colors to mirror the true colors of the pieces. But now I can take the jpgs and print them off, file them as references for the next time I want to use these glazes.

Here's Fire Opal on a bowl. I've tried this one before, and I find it interesting, but I'm just not sure what to do with it.

There's another Coyote glaze called Rhubarb that is very much like it. You really have to be careful with a pink-ish glaze. It can come off as being frivolous. It will be interesting to combine it with eggplant or a tan glaze.

Eggplant is a very intriguing glaze. Here it is applied thickly to a bowl. The color is very rich. It turns out matt and pretty well covers everything.

Here is Eggplant applied to a small bowl. The green is the result of a thinner layer than the purple, which is two layers thick. This glaze will be one that will either wow you or drive you crazy.

Creamy Matt fires rather thickly, gives a uniform matt finish. It might be a good base to bounce other glazes off of. I will try some shiny transparent on it and see what happens. It holds it's own up against Copper Blue, which is runny.

The Iron Matt is also good covering and a pleasing brown, but cannot be used for food surfaces. I'll probably go back to the plain Iron Tan from Seattle Pottery Supply I have been using because of that.

Eggplant over Creamy Matt could be an interesting combination as well as Eggplant over Iron Matt.

And Copper Blue looks good over Tan Matt. Almost turns into lizard skin where it's thick.

I am really interested in the result of Eggplant over Copper Blue. That could be a real winner.

Three Clays; Two Glazes

I picked up three different clays from the supplier when I got the kiln. They're all Laguna clays. One is porcelain, the other two a red and a very dark, nearly black clay. It will be interesting to see how they handle and fire.

I also got a couple of fairly neutral glazes to experiment with. And I'll include some underglazes into the mix to test how they perform.

Sounds fairly simple? I began brainstorming about how I can find out the most with just these elements.

I think best with a pen in my hand and a piece of paper. And this is what I came up with and this is what I came up with. I make test tiles that are curved on the bottom so I can see how the glaze pools. I use a bamboo skewer to impress two lines to see how the glaze breaks. Later I'll make a hanging board so I can see all the glazes at a glance.

I'll bisque 3 samples for clay reference: On to remain bisqued, one to fire to cone 5 and one burnished.

Three will be a sample of one glaze: All three dipped two times with one dipped a third time and held as an example of just that glaze. The other two will be held in reserve for further tests of that glaze.



These test tiles are 4 inches long and two inches wide. The clay and cone are incised on the backside of the clay.

The same applies for the other glaze. With the third set of tiles, I'll dip an over/under test with one glaze, then reverse the test for the other glaze. The 2nd and 3rd tiles will be held in reserve to use with a third glaze in the future.

And I'll make sure I label the backs of these tiles, take notes and photograph the results.

I will also make one 6" square tile of each clay and do an underglaze test plus an over/under glaze test.

I toyed with the idea of making a square vessel that could show the two glazes and how they reacted on a vertical surface with indentations and with relief elements, yet integrated enough to make an inti grated piece. After I roll out all that I need for test pieces, I'll see if I have enough room.

Always nice to have two references for any glaze.