Fake Ash Glaze Testing Help

[Randy McCall]

Ron Roy has asked me to test some fake ash glazes to see if he can develop a fake ash that does not have pinholes or any bubbles.

 

If any one would like to test these and get back to the group with results I would be grateful as it will probably be a few weeks before I can fire again.

 

Here are the glazes.

 

Recipe Name:  Fake Ash Test 1

Cone:  6     Color:  Ash
Firing:  Oxidation     Surface:  Glossy

Amount     Ingredient
47          Red Art
22          Whiting
13          Nepheline Syenite
4          Frit--Ferro 3134
14          Dolomite

100         Total

Recipe Name:  Fake Ash Test 2

Cone:  6     Color:  Ash
Firing:  Oxidation     Surface:  Glossy

Amount     Ingredient
46.5          Red Art
22          Whiting
13          Nepheline Syenite
5.8          Frit--Ferro 3134
12.8          Dolomite

100         Total

 

Recipe Name:  Fake Ash Test 3

Cone:  6     Color:  Ash
Firing:  Oxidation     Surface:  Glossy

Amount     Ingredient
46          Red Art
22          Whiting
13          Nepheline Syenite
7.5          Frit--Ferro 3134
11.5          Dolomite

100         Total

Recipe Name:  Fake Ash Test 4

Cone:  6     Color:  Ash
Firing:  Oxidation     Surface:  Glossy

Amount     Ingredient
45.5          Red Art
22          Whiting
13          Nepheline Syenite
9.3          Frit--Ferro 3134
10.3          Dolomite

100         Total

Recipe Name:  Fake Ash Test 5

Cone:  6     Color:  ash
Firing:  Oxidation     Surface:  Glossy

Amount     Ingredient
45          Red Art
22          Whiting
13          Nepheline Syenite
11          Frit--Ferro 3134
9          Dolomite

100         Total

 

[susan claysmith]

I tested these 5 Fake Ash Glazes this week, and will post pictures of the results tomorrow.

[Randy McCall]

Susan

Thanks alot. Your results will be a big help in developing a fault free Fake Ash Glaze at Cone 6.

[susan claysmith]

Here are the fronts and backs of all the 5 tests seen together. Susan

[Randy McCall]

Susan I looked at the pictures and it appears from what I can see that #5 would be the best with fewer pinholes and more flow. But what do you think from seeing them directly.

[Randy McCall]

Looked at these again and maybe I like #4 better. You did great. Wonderful tests.

[Randy McCall]

It will be interesting to see where various oxides takes this glaze. I agree with you that I like #4. I am sure oxides will cause it to flux more. Can't wait to try this glaze. These tests were done to share them here and on ClayArt with other potters. Thanks to you and Ron Roy our Cone 6 glazers should have another good fake ash glaze in their palette minus the pinholes.

[susan claysmith]

Here are a few more details about the tests I did. They were all based on 100 gr batches and I sieved the samples after mixing. The clay body is Plainsman P300. My kiln holds the heat very well, it cools very slowly and I do not downfire. The glazes were brushed on and I applied more on one side of both the fronts and backs, however there is probably a reasonable amount of variation between the applications. Since they were brushed, the textured front sides picked up heavier amounts of glaze in the deeper areas. Somewhere I have a magnifying loupe, but I don't know where I put it! It would sure be nice to have a really close look.

#1 - very matte, some pinholing in areas where glaze is thicker, one tiny pinhole on back side where glaze is thicker.

#2 - a bit more sheen and more fluid than #1, less pinholing on front, no visible pinholing on back.

#3 - more sheen and more fluid than #2, no pinholing front or back. Where the glaze is pooling it appears to be crystalizing and where it is pooled and crystalized, takes on a rough texture.

#4 - more sheen and more fluid than 3, no pinholing front or back. Where the glaze is pooled, it takes on a glassier appearance and has less roughness than 3.

#5 - Most fluid of all five. Very glassy where it pools. Visible crazing in pooled areas.

I think that I prefer the look of #3, but #4 has less roughness in the glassy areas. I can see that I would need to factor in the flow, when chooosing where to apply this glaze. I am hoping to do another firing in a few days, so I will apply a couple of these to a couple of pieces and post the results. Susan
Susan

[susan claysmith]

I did another firing a few days ago and decided to try my test sample of #3 on a piece. Here are two pieces that I tested it on. On the first, it is on the outside of the piece with a bit of copper carbonate brushed on the relief areas. It ran like crazy, the firing was to cone 6 all the way on that shelf. I love the effect, but I would confine it to the upper part of a vertical piece.
The second example is a test of my first crack at single firing. I had made a bunch of sushi plates a few days prior to glaze firing and tested out different glazes I had that have a high clay content. I am pretty happy with the results. This piece was using one of the fake wood ash glazes as well.

[Nancy Gallagher]

I like this. I know I'm coming late to the party, but are these as green as they appear on my monitor? (olive clear color) and on the sushi plate and vase, did you also brush the pseudo ash on?

[susan claysmith]

Hi Nancy - The colour is very acurate to what I see on my monitor.  I brushed everything I tested with a 2" hake brush.  I would guess that there would be a bit less running on a stoneware body as the body would have less of a fluxing effect on the glaze.  Susan
Nancy Gallagher said:

I like this. I know I'm coming late to the party, but are these as green as they appear on my monitor? (olive clear color) and on the sushi plate and vase, did you also brush the pseudo ash on?

[Nancy Gallagher]

Thank you! I wasn't sure if you'd still be reading this. It's been some time. I will actually be testing it over a vitreous engobe which I know sounds strange, but I have an idea brewing.

[susan claysmith]

It will be intersting to see your results - make sure that you get a picture up on the site.  One of the nice functionalities of this site is that as soon as you add a comment, I get notification, so although I haven't spent a ton of time on the site recently, I knew right away tht you had added to the discussion.  Susan