Will Mosher on tue 31 mar 98
I am not sure about some of the terms you use, but I have used sawdust
mixed into clay before, to great effect. So here's what I know, wether
you wanted it or not.
Due to the way sawdust burns out in the kiln, it leaves behind all these
spaces that help the steam escape from the clay body, and as a result
prevents disasterous blowouts on thick works. This is especially helpful
when doing clay sculpture, though I've never discovered exactly how thick
you could safely go.
When thrown, you have limitations on the thinness of your pot's walls,
since long fibers can catch on the outside of the pot and tear on the
inside. However, the physical structure of the fibers gives the clay much
more structural integrity, so I have found it easier to go larger, found
more support in precarious situations, and have been able to fiddle with
it longer without loss of strength. (i.e. use "too much" water)
The burning out process reduces the weight of your wares by a significant
amount, sometimes producing a very pleasant surprise when a heavy or
clunky looking pot is picked up and found to be much lighter. There is a
corresponding surface texture, though on thrown works it is not obvious
unless you have stretched the clay thin.
The presence of sawdust in clay does change some important factors,
though. It is very absorbant (duh), and promotes the growth of bacteria.
I mean, it stinks after a few days, especially as slip or in the waste
bucket. As I understand it, the organics given off by bacteria can help
make a clay "longer" as it ages, and I found the sawdust mix of mine was
a bit longer. I know that some of the sawdust I was using was from
plywood, and likely contained small amounts of formadahyde, so I was
hoping that some of the chemistry types on the list would comment on
that.
Btw, could you tell me what "terra sig" and "groats" are?
Eating peppermint-vanilla ice cream in MA
--Will
On Sun, 29 Mar 1998 13:42:34 EST Eleanora Eden writes:
>----------------------------Original
>So. Paperclay works a treat. Tiles fire easy and stay flat. What
>about using wood in the form of powder, dust, or tiny chips (let's call
them
>groats)? I have been clam-happy with paper clay using pulp except
>that the stuff is so hard to cut or smooth the edges......and for me
wood is
>far more easily available. I have just done tests using powder from
the
>sanderbag.....suggested to me by the post on using clay dust out of
>the filter for terra sig.....which has the extra positive of stiffening
up
>the clay slurry for immediate usability and also can be thrown....ya
call
>that throwing....and using these tiny wood groats also has made me a
nice
>tile with no drying or firing problems.
>
>Now for usage requiring dry strength I can appreciate the advantages
>of the longer paper fibers....but for tile-making can anybody see
drawbacks
>in using wood instead of paper? Anybody doing this?
>
>Eleanora....where the robins are mighty territorial this morning......
>
>.............
>Eleanora Eden 802 869-2003
>Paradise Hill
>Bellows Falls, VT 05101 eden@sover.net
>
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