New Troubles With Frit 3195

[CalliBlue]

About 12 years ago, I was using the following formula Transparent 06-04 with no problems. I do a short soak, 10 min, with C 05 firing.

 

Frit 3195 85

EPK 15

Bentonite 2

 

Went back to doing low-fire work last year, but when I finished my old supply of Frit 3195 and started on a new batch, I began to have major problems with Tiny Bubbles in the fired glaze. Smooth surface, but fizzy, foamy, bubbly appearance underneath. So odd. My first failure firing had a whole shelf of mugs glazed with "old" glaze---fired fine, no bubbles. Next shelf, mostly mugs glazed with a fresh batch of glaze with new frit 3195 --all fizzy/bubbly (but 2 mugs with old glaze on same shelf were fine).

 

I use red eathenware clay body, so a bubble-free glaze is important.

 

Solutions I've tried:

 

New formula with some 3195 replaced with F 3134. Helped, but tends to go boron blue. Not good for me.

Bought new F 3195. No change.

Apply thinner. Helps, but not much.

Tried using more or less 3195, adding Silica, trying different frits and combinations with 3195 (tried 3124, etc), using less Alumina in formula, etc. Still tends to fizzyness.

 

I now use a clear 05 with this formula: But I don't like it as well, and WISH I could get my old reliable Frit 3195 Clear Glaze working again!

 

F3124  47.5

F3269  37.5

EPK     15

Bentonite 2

 

Just wondering if anybody else has noticed Frit 3195 melting differently.

 

Thanks!

 

 

 

 

[enbarro]

Hi, I've read that frit manufacturers change formulas over. That might be a possible reason. Most probably some mixing/recipe detail you forgot. Cones bending temperatures also changed some years ago, maybe firing to cone 04 might help.

 

Your version of the recipe has quite a bit more Kaolin than what I've usually seen, which is 88-92% frit 3195 and 8-12% ball clay or Kaolin. So, you could try a line blend to see if you find the right combo. Frit 3195 is listed as being a well balanced formulation typically used as an all-fritted, cone 06/04 glossy glaze. As long you can keep it in suspension somehow you should be able lower the amount of EPK.

 

Normally adding clay to a low fire glaze raises the melting cone. This glazes is really high in Al and Boron, and I'm not sure how that changes the equation.

 

I've read several places that a thin coat is the key. That being said, I tried this recipe a few years ago with no luck. Don't remember what was problem or found the test tiles.

 

Have you tried any colorants with this recipe?

 

 

Also, why do you prefer it to the frit 3269 recipe? This recipe I haven't seen before. Does it craze? It reacts different to the colorants you use?

[CalliBlue]

I liked it because it was simple, fired clear, and the red clay underneath looked deep and rich. I use white slip on portions of my pots, and use underglaze colors on these parts. I was able to get a very stable, smooth coat of glaze, not runny, no crazing---"before" my troubles, that is. My new glaze, over colorants, doesn't reveal as deep a color, and the red clay doesn't look as red, either. So that's why I like it better than the F3269 glaze.

 

I have tried thin coats, and yes this helps, but it still has fizzy places. My "old" glaze wasn't so sensitive to thickness---I never remember having to fiddle with that so much.

 

I recently tested this:

F3195  90

EPK       5

Silica     5

Benton.  2

 

Results--still same fizzy problem.

 

I've mixed up multiple new batches while troubleshooting, so I don't think it's a mix or weigh error.

 

Thanks for your comments.

[enbarro]

HI,

I didn’t mean that you necessarily made a mixing error, rather that there’s little stuff like the amount of water, type of brush etc that can make a difference. Also since at some point your old batch of glaze also had the same problem it might be a good idea to check you firing schedule, kiln elements and if your are having voltage variations.

This links talks about adding aluminum hydroxide… and also lists some variation on the recipe.

http://www.potters.org/subject103127.htm

I’m going to experiment with this base soon because I still have #8 of frit 3195… but I’m firing cone 04-02 and I’m ok with bubbles I’m looking for craze free durable glazes and color response. Still, if you find a solution to the problems please post it here. There isn’t much information for people working with earthenware.

Thanks,