single firing ash glazes

It seems to me that you need to deflocculate your glazes so that they contain as little water as possible, and then apply them in stages over time -- in other words, first, the insides -- then let them dry Second, the rims -- let them. Third, the outsides, etc. If they get water in increments perhaps they'll be less inclined to crack.

Ceramics Monthly for December, 1994, has an article by Richard Aerni on "Single-Fired Ash Glazing." In it, he mentions that he sprays his ash glazes in stages onto raw pots, but doesn't say at what stage of dryness. He also says he prepares just enough glazes for the days work because his unwashed glazes flocculate over time.

Good luck -- Let us know how you solve this problem.

Marco

i guess in a weird way you could put wood in your bowls to burn, ash, and glaze in the same fire? or pile on raw ash with no water? or what about mixing ash in Elmer's Glue (that white water based glue) and glue the glaze to your pot?

i never tried any of this, but their must be a liquid carrier that could be used to add the ash to the pot without watering down the pot?

i mess around with "black fired" pots where i mix graphite with salad oil & apply this to bisque pots.

possibly a mix of salad oil & ash would head in your direction?

see ya

steve

I've mixed up "regular" (non-ash) glazes using canola oil instead of water for just this purpose. I wanted to single-fire some pieces that were bone dry, and may usual water-based glazes caused the pieces to crack from water re-absorption, even on a single application to just the inside of the piece. The oil-based glaze did the trick, but it was a problem to handle the pieces to get them into the kiln. The oil vanished into the interior of the clay, leaving the glaze as a powdery residue on the surface, sort of like the scales on butterfly wings... the slightest touch would mar it.

Perhaps straight ash in oil wouldn't have this problem.

I've been thinking of other bases instead of this oil, which might work better, but haven't tried any yet. If I were going to use this regularly, and not just as an experiment or "in a pinch", I'd want to find something that not only worked, but was inexpensive and readily available, and that didn't release noxious fumes when burning out in the kiln. There is also the issue of flammability during the application, if you try other organic sovents, etc. For example, gasoline might work, but I'm sure not going to try it! I'll probably try concentrated rubbing alcohol when I next get into a pinch, but it's too expensive for everyday use even if it works perfectly.

Anyone have any other suggestions for cheap non-aqueous bases to try?

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

This sounds interesting--what does it look like? How do you fire it, is it a pit firing type of thing? What kind of mix is it, and is it painted on or do you dip the pots?

Deb R.

i use about 1 quart of salad oil with 1 teaspoon of graphite. i apply to bisque pots.

the pots are placed in a metal can surounded with sawdust. i close the can, and put a brick on the top. in the kiln i fire to about "can red". ~ when the can turns red.

the pots are sort of pit fired, but VERY black from the concentration of sawdust & the graphite.

i 1st saw the use of graphite about 10 years ago via ceramics monthly magazine. the author claimed to get gun metal black results - and i get very similar.

i sometimes throw pots that look american indian & use this process to get "low budget" indian pots.

a mad scientist friend of mine says that graphite, as a special form of carbon, encourages regular carbon to convert to the graphite form in the firing & that is why the color is richer then usual carbon black.

see ya

steve

Thanks--this is great info. A couple more questions--do you burnish first? What claybody do you typically use?

I'm looking forward to trying this out sometime.

Deb R.

thanks for the suggestions, I think I'll try defloculating first, before mucking about with oil and glue and gasoline!!!??? I've got some sodium silicate in the workshop.

I'll let you know what happens.

All the best. Alistair.

sometimes i burnish, sometimes i don't.

i use typically soldate 60 cone 10 clay, but also porcelain sometimes.

the richness of the black is great no matter what the surface finish.

see ya

steve

Deborah M Riel wrote:

concentration

sometimes i burnish, sometimes i don't.

i use typically soldate 60 cone 10 clay, but also porcelain sometimes.

the richness of the black is great no matter what the surface finish.

see ya

steve

Deborah M Riel wrote:

concentration