Maurice Weitman on sat 4 oct 03
Howdy,
I'd appreciate any of your recent experiences with commercial clay
bodies at ^6 ox, and any recommendations for any other bodies for
throwing that are available on the left coast. (Aardvark, Claymaker,
Imco, and Laguna, and Quyle are commonly available here.)
In making the shift from cone 10 reduction to cone 6 ox, I've been
using MC6G as a guide. So, a bonus for me, if you've had any good
results with cone 6 bodies using the glazes in John and Ron's
Mastering Cone 6 Glazes, that'd be most helpful.
Unfortunately, the (Standard Ceramics) bodies they use in their tests
and samples are only available east of Ohio. (I quote Ron's response
to my query to him at the end of this message.)
Many folks around here have recommended Imco's Navajo Wheel as a good
throwing clay. But Bill Abright told me that Navajo Wheel was a
great throwing clay, but would bloat at cone 6. And in searching the
archives, I found one reference to Navajo Wheel bloating at cone 6.
Eric Struck, Imco's tech support told me that despite their online
catalog listing their Navajo Wheel bodies as being recommended for
cone 5, "... Navajo Wheel clays work well at cone 6. The shrinkage
and absorption should be just about the same but slightly higher
shrinkage and slightly
lower absorption. Navajo Wheel is a very red clay and at cone 6 it
will fire brown."
Some folks have had good things to say about Imco's cone 6 porcelain
body, and Craig Martell has kindly sent me his suggestions for
formulating my own cone 6 porcelain.
Thanks for your help.
Regards,
Maurice
Here's RR's response:
>Choosing a clay body is not easy - you must decide what is the most
>important thing - workability (includes drying), colour, and how it
>fits your glazes.
>
>Most clay manufactures don't test their clays - it would be a big
>help if they did because you could eliminate those that did not leak
>at whatever cone you decided to fire at.
>
>Ask on ClayArt - what bodies people who live near you have found
>that work well at cone 6 - make sure to ask if any of them have
>tested for shrinkage and absorbency.
>
>Buy a few different ones - that will mature at the temperature you
>decide to fire at - I assume that is cone 6.
>
>Start throwing them and make some test pieces to use with our glazes
>in chapter five - to test for expansion - you will then have a good
>idea which clays will work with our glazes.
>
>As soon as you get the clays make test bars of each - about 4. Let
>me know if you need my instructions for testing for shrinkage and
>absorbency.
>
>You decide - white stoneware - or buff or brown - with grog or
>without - maybe porcelain. Porcelain is harder to work with so maybe
>stoneware to start with.
>
>Take a close look at the glaze in our book - some work with
>stoneware better than porcelain and others will look better on
>porcelain.
>
>You want to start with a clay that will hold water - that is for
>sure - and there are many that don't so use that as a main criteria.
Thanks.
Regards,
Maurice
Cindy Hart on sun 5 oct 03
I use Miller (now Laguna) 66 for throwing and handbuilding. It is a white
clay and throws well. Shrinkage is around 12%. 65 has no sand so may be
better to throw with but I like 66. Floating Blue, Variegated Blue,(Ron and
Johns Book), Kemp 17, Randys Red and almost all glazes I have tried are
great on the white clay. No problems...
I also use Miller 50 and 55. Glazes don't look that great on 50, they tend
to be dull and/or pinhole but it is a nice "sandy" looking clay body and I
leave it unglazed on most of the pots I use it for. Again, I think the
shrinkage is around 12%. I tested absorption on both these clays and
forget the exact number but it was below 3% at cone 6.
I haven't used 55 for awhile but have recently tried Standard 112. Have
not tested for shrinkage or absorption but loved throwing with it and it
took glazes well..
Sid in SC
John Anthony on sun 5 oct 03
Hi - I have used Miller 55 cone 6 clay for a long time; it was the shop
cone 6 stoneware at The Clay Studio
in Philadelphia when I was there. It's a nice throwing clay, seems to
have a bit of iron in it, and trims nicely-
perhaps there's some larger particle fireclay- I'm not sure - but it
has a bit of texture when I use my regular
trimming tool ( which is a steel kanna like the one in the Cushing
handbook), and I like that. I don't do much porcelain,
but I have been using some Bmix5, testing glazes for a friend, and
that's a nice white firing claybody- also very easy to throw.
John A
http://www.redhillpottery.com
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