recycling clay and old kilns

[mrpeders]

I'm learning so much from these postings. I'm hoping you can answer two questions from a experimenting newcomer.

1. I have some blocks of dried out clay. I covered one with distilled water in a small plastic bucket. After three weeks, it seemed completely sloppy wet to me, so I poured off the extra water and used a power drill with a drywall mixer to try to get the moisture the same throughout. After I thought it seemed fairly good, I scooped some out onto some greenboard to see if I could dry it out enough to use it. It seems there are still pieces of harder clay mixed in. Any suggestions? I hear talk of screening, but I haven't seen any examples anywhere. Will window screen work? I hate to throw out anything I can reuse, and I don't have access to a pug mill.

 

2. I also have a large older kiln with a kiln sitter. I'm firing to 04 - 05 with low fired glazes. I'm still trying to adjust the kiln setter. An 05 takes about 5 hours. A kiln repairman said I should adjust the "catch" so it just barely holds. All elements are blazing hot, and I'm not cooling too quickly. When I fire, the cone in the sitter is just slightly bent, and the 05 witness cone I set inside was also just slightly bent. The kiln does shut off, however. The load I just did was small tiles with a variety of glazes which I also inherited. I brushed two coats on each tile. Many of the tiles had small pitting. Does this mean the kiln is not reaching 05 temperatures? Would it be more effective to just watch the time and increase it by 30 minutes until I find a time when the pitting disappears. Even the brand new glaze (Amoco) tiles had small pitting.

 

Thank you so much for any help.

 

 

 

 

[Mark C.]

I'm learning so much from these postings. I'm hoping you can answer two questions from a experimenting newcomer.

1. I have some blocks of dried out clay. I covered one with distilled water in a small plastic bucket. After three weeks, it seemed completely sloppy wet to me, so I poured off the extra water and used a power drill with a drywall mixer to try to get the moisture the same throughout. After I thought it seemed fairly good, I scooped some out onto some greenboard to see if I could dry it out enough to use it. It seems there are still pieces of harder clay mixed in. Any suggestions? I hear talk of screening, but I haven't seen any examples anywhere. Will window screen work? I hate to throw out anything I can reuse, and I don't have access to a pug mill.

 

 

I have no idea on why distilled water as regular water will do fine

I also need more info on the"clay." Is it porcelain (white) ?low fire white? or low fire brown?Many low fire bodies are high in talc.

I would have smashed the "clay" when dry into smaller pieces then added some water

If you can power mix it with tools its way to wet.

You have not yet gotten it uniformly wet .

I would bag it in plastic bags with some water and let sit for more time.

Some low fire folks will add more I'm sure.

 

2. I also have a large older kiln with a kiln sitter. I'm firing to 04 - 05 with low fired glazes. I'm still trying to adjust the kiln setter. An 05 takes about 5 hours. A kiln repairman said I should adjust the "catch" so it just barely holds. All elements are blazing hot, and I'm not cooling too quickly. When I fire, the cone in the sitter is just slightly bent, and the 05 witness cone I set inside was also just slightly bent. The kiln does shut off, however. The load I just did was small tiles with a variety of glazes which I also inherited. I brushed two coats on each tile. Many of the tiles had small pitting. Does this mean the kiln is not reaching 05 temperatures? Would it be more effective to just watch the time and increase it by 30 minutes until I find a time when the pitting disappears. Even the brand new glaze (Amoco) tiles had small pitting.

 

Thank you so much for any help.

 

The witness cone needs to be a full size cone and should be bent even with base at shut off-adjust your kiln sitter rod as per the instructions (usually old kilns are Dawson controlled)Get ahold of them if you have none.

As far as pitting my guess is a fast fire with fast cooling maybe under fired as well. Make sure those tiles are clean (dust free) before glazing.

This is also an area for low fire experts which I'm not.

Mark

 

 

 

 

 

 

 

[Chris Campbell]

A lazy way to rehydrate dried out clay is to wrap it in a wet towel, put it in a plastic bag ... check after one week to see if you need to re wet the towel. By week two it will be soft enough to use or to cut in smaller pieces which go back in the wet towel for a while. Eventually it will be evenly hydrated.

[AmeriSwede]

A lazy way to rehydrate dried out clay is to wrap it in a wet towel, put it in a plastic bag ... check after one week to see if you need to re wet the towel. By week two it will be soft enough to use or to cut in smaller pieces which go back in the wet towel for a while. Eventually it will be evenly hydrated.

 

 

Thanks for posting that, Chris .... I've a few (10 kilo) blocks of terra-cotta that dried a bit during this last cold winter in the studio.... and your clarifying prefaced description of 'lazy way to rehydrate...' more than amply applies to my desire to spend time dealing with it.

 

-----Rick

[Jeri]

I have an old kiln (26years old) with a kiln sitter also. In order to know for sure if you're under firing, I'd suggest using a set of two, or three witness cones. If you're desired range and firing bar/cone (in the sitter) is ^05, use ^04, ^05, and ^06. This will give you a more accurate idea of where you're firing. I have to use a cone higher than the desired range, e.g. I want ^06, I use ^05 in the sitter.

 

When I need to add moisture to the clay, I usually cut it into smaller bricks, add the water and wedge it about a week later, and repeat if needed. (That's if the clay isn't completely dry)

 

Hope this helps a bit.

 

Jeri Lynne

[Denice]

It sounds like everyone gave you pretty good advice, I would like to suggest you take some pottery courses and volunteer to help load the kilns and unload them you will gain a lot of the knowledge you need to run your own kiln. If you don't have classes available to you the library usually has a good selection of books that covers all aspects of pottery production. Denice

[teardrop]

Youtube is also an excellent resource. Typing in "loading a kiln" brings up multiple vids...including vids from kiln manufacturers.

 

best of luck

 

teardrop

[TJR]

On glaze pitting-

1. Your tiles may be dirty. I wash all my bisque the day before I glaze fire. I know this is an extra step, but it has saved my work from pitting. I just use glaze tongs and dip in and out of a bucket of water.

2. You may be firing your glaze kiln too fast and not getting a good glaze development. Eight hours for a glaze is not out of line.

TJR.

[Arnold Howard]

2. I also have a large older kiln with a kiln sitter. I'm firing to 04 - 05 with low fired glazes. I'm still trying to adjust the kiln setter. An 05 takes about 5 hours. A kiln repairman said I should adjust the "catch" so it just barely holds.

 

You will need a firing gauge to adjust the Kiln Sitter. This manual covers Kiln Sitter adjustments, which start on page 5.

 

http://www.paragonwe...-Kilns-ver2.pdf

 

Sincerely,

 

Arnold Howard

Paragon Industries, L.P., Mesquite, Texas USA

ahoward@paragonweb.com / www.paragonweb.com

[mrpeders]

Thank you so much for the expert advice. The paragon info will be very helpful. The blocks of clay are sitting in wet towels as I write, and hopefully can be reused. Your advice about cleaning was probably the problem. I was so excited about seeing what the mystery glazes would do, that I forgot that step. I'm pretty homebound with the care of elderly blessings, but youtube has been a big help. Still not so sure about the kiln, but trying a 04 cone when I need a longer fire is something I'll try. Guess I need to study the sitter info first. Thank you again for your generous help.