Dave Finkelnburg on tue 9 may 00
Ron,
Thankyou! This is totally new information for me. I appreciate your
note!
I am using mainly EPK and OM #4, so you've given me information on the
right clays. I can sure see a difference between them in this parameter.
Thanks again!
Dave Finkelnburg
-----Original Message-----
From: Ron Roy
To: CLAYART@LSV.UKY.EDU
Date: Sunday, May 07, 2000 10:26 PM
Subject: Re: High-clay glaze help needed
----------------------------Original message----------------------------
Hi Dave - sorry this got by me - I don't know which way is up these days
I'm so busy.
Clay companies publish modulus of rupture numbers for all their clays -
you did not include a list but here are a few.
These are for 50% clay and 50% silica.
C&C - 715
New Foundry Hill cream - 700
Tenn #1 - SGP - 410
M7D - 1750
Kent Stn - 610
KTS-2 - 650
OM#4 - 850
EPK - 300 - see how low this is - glaze powders easily if no Bentonite
present.
Bell Dark - 690 - this is the one I use most.
Pioneer - 300-400
Tile 6 - unreliable info
The quick fix is to add some (2%) bentonite - or reformulate using at least
some of a clay with finer particle size.
RR
>----------------------------Original message----------------------------
>Ron,
> This is really interesting! What is MOR? How does one find out what
it
>is for a particular clay, or possibly just for types of clay in general?
> The water here is hard, not as bad as some, but generally high in
>calcium, etc. How would that affect which clay to use in a recipe?
> Right now I'm selecting clays mainly on iron content and size. Low
clay
>recipes where iron isn't an issue tend to get ball clays to aid suspension.
>EPK is the lowest iron clay I have, and I use it where I want a low-iron
>glaze. For high-iron glazes I have been using Redart, but not so much that
>it's been a problem in application. Anyway, these are the clays.
> Dave Finkelnburg
>-----Original Message-----
>From: Ron Roy
>To: CLAYART@LSV.UKY.EDU
>Date: Saturday, April 15, 2000 8:35 PM
>Subject: Re: High-clay glaze help needed
>
>
>----------------------------Original message----------------------------
>Hi Dave,
>
>Just how much clay and what kind are the questions - sometimes all that is
>needed is a change if clays - to ones which have a higher MOR - stronger
>dry strength.
>
>Finer particle clays will work some times. Much depends on you water.
>Calcining is one answer but not always the right one.
>
>Certainly don't start firing them until they are dry and dry em slow.
>
>RR
>
>>----------------------------Original message----------------------------
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
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