Tom Sawyer on mon 9 jun 03
I have been using a redart slip glaze under other cone 6 glazes with some
interesting results. The formula for this is:
Lithium 10
Spodumene 10
Redart 80
I've had no trouble until I used the following glaze over the above:
Ron and John's Teal Blue
NS 35
Silica 30
Whiting 18
3134 12
OM-4 5
Tin 8
CoCO3 4
Turns out this is really a beautiful glaze combination but I get shivering.
Which of the above should be modified? One? Both? Suggestions appreciated.
Thanks
Tom Sawyer
tsawyer@cfl.rr.com
John Britt on mon 9 jun 03
Tom,
Sounds to me like the lithium is the problem. Lithium 10 and Spodumene
(lithium feldspar) 10. This is probably too much.
John Britt
Penland
Craig Martell on mon 9 jun 03
Tom stated:
>I have been using a redart slip glaze under other cone 6 glazes with some
>interesting results. The formula for this is:
>Lithium 10
>Spodumene 10
>Redart 80
Hi:
Get real Tom. That's not a formula, it's a recipe. :>)
Yeah, I would bet this slip would give interesting results. But the
problem is, way too much lithium. I did convert this to formula using two
different material databases and got the same value for LiO in the Seger
Formula. It is 0.68 which is a couple of light years beyond the danger
zone when considering lithium. While this concoction may work just fine at
times, there is a great potential here for trouble.
regards, Craig Martell Hopewell, Oregon
John Post on mon 9 jun 03
Hi Tom,
It's the lithium that is most likely causing the shivering problems. 10% is
way too much in most glazes. Try cutting it down to 2% or eliminating it
completely. The glaze that is going over the top looks like it is well
fluxed enough to interact with your slip glaze and not need the addition of
the lithium.
I have no idea what your local clay is like, but if you have earthenware
clay available locally, it isn't too much work to make up a 5 gallon bucket
of the stuff to use as a slip.
Cheers,
John Post
I have been using a redart slip glaze under other cone 6 glazes with some
interesting results. The formula for this is:
Lithium 10
Spodumene 10
Redart 80
I've had no trouble until I used the following glaze over the above:
Ron and John's Teal Blue
NS 35
Silica 30
Whiting 18
3134 12
OM-4 5
Tin 8
CoCO3 4
Turns out this is really a beautiful glaze combination but I get shivering.
Which of the above should be modified? One? Both? Suggestions appreciated.
Thanks
Tom Sawyer
tsawyer@cfl.rr.com
tony@DIGITALFIRE.AB.CA on tue 10 jun 03
There is an article in the new American Ceramic Society
magazine on Lithium. It is written by someone from Tanco
in Manitoba. It is very informative and the author makes
one statement that I think sums up the predictability of
lithium in glaze formulas: It does not give \'straight-line
performance\'. Also, that is a lot of lithium, normally only
a couple of percent or less is used. This is going to be
shiver city I think.
-------8<--------
Tom stated:
>I have been using a redart slip glaze under other cone 6 glazes with some
>interesting results. The formula for this is:
>Lithium 10
>Spodumene 10
>Redart 80
Hi:
Get real Tom. That\'s not a formula, it\'s a recipe. :>)
Yeah, I would bet this slip would give interesting results. But the
problem is, way too much lithium. I did convert this to formula using two
different material databases and got the same value for LiO in the Seger
Formula. It is 0.68 which is a couple of light years beyond the danger
zone when considering lithium. While this concoction may work just fine at
times, there is a great potential here for trouble.
regards, Craig Martell Hopewell, Oregon
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--------
Tony Hansen, Digitalfire Corp.
John Hesselberth on tue 10 jun 03
Hi Tom,
Ron is down here in the US visiting me (and straightening me out--he
has to do that periodically) so I showed him your problem.
Here are 2 modified slip recipes that he guarantees will solve your
problem --which as others have pointed out is caused by the lithium.
Var 1
Li 2.0
Spod 14
Red Art 50
G200 25
Whiting 9
RIO 2
Total 102.0
Var 2
Li 1.5
Spod 16
Red Art 62.5
G200 10
Dolomite 10
RIO 1.5
Total 101.5
On Monday, June 9, 2003, at 09:12 AM, Tom Sawyer wrote:
> I have been using a redart slip glaze under other cone 6 glazes with
> some
> interesting results. The formula for this is:
> Lithium 10
> Spodumene 10
> Redart 80
>
> I've had no trouble until I used the following glaze over the above:
> Ron and John's Teal Blue
> NS 35
> Silica 30
> Whiting 18
> 3134 12
> OM-4 5
> Tin 8
> CoCO3 4
>
> Turns out this is really a beautiful glaze combination but I get
> shivering.
> Which of the above should be modified? One? Both? Suggestions
> appreciated.
> Thanks
> Tom Sawyer
> tsawyer@cfl.rr.com
>
> _______________________________________________________________________
> _______
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>
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