Val Cushing’s Vitreous White Stoneware ^6

[Marko]

Hi everyone, it’s been a while. So sorry, just so many things disrupting my pottery life, but slowly I am coming back in the game, as they say.   So I hope everyone is well.  And having Fun. 

So I have always wanted to make my own clay and found Val Cushing recipe in his book I bought online.  But I am having troubles with the quality of the finished mix.   I followed the recipe.  I even used Kona F-4 that my supplier just ran out of, so I will use Minspar 200,  unless someone has a better option.

One of the problems I have is in the throwing. It’s so plastic it is hard to throw even mugs, unless I throw thick and then trim.  I thought of add grog, but I don’t want to throw sandpaper, hehe.  Suggests?

Also, does the clay need to age?

Kona F-4..........30

C&C...................25

Grolleg..............25

Silica...................16

FF 3124.............4

Bentonite  2%

[Min]

 

I’m not really understanding the problem, is it that the walls are “flabby” and won’t support the weight of the clay unless thick?

Recipe looks okay, how did you mix the clay? Slurry then dried and wedged or ?  For sure clay typically throws better after aging, especially ones that aren’t slurry mixed.

Nice to see you back here.

[Marko]

Yes. And thank you for asking, Min. I have difficulty keeping the form from slogging unless I keep the wall at least 1/4". 

I do not have this problem with pre-made clay like B-mix. 

I was hoping someone could guild me to making this recipe less temperamental.  More user friendly.

I dry mix it in a 5 gal bucket and then shake the 5 gal aggressively till I feel it is a good mix. And then let it settle before I pug it.

[Marko]

26 minutes ago, Min said:

 

I’m not really understanding the problem, is it that the walls are “flabby” and won’t support the weight of the clay unless thick?

Recipe looks okay, how did you mix the clay? Slurry then dried and wedged or ?  For sure clay typically throws better after aging, especially ones that aren’t slurry mixed.

Nice to see you back here.

Yes. And thank you for asking, Min. I have difficulty keeping the form from slogging unless I keep the wall at least 1/4".  I do not have this problem with pre-made clay like B-mix.  I was hoping someone could guild me to making this recipe less temperamental.  More user friendly. I dry mix it in a 5 gal bucket and then shake the 5 gal aggressively till I feel it is a good mix. And then let it settle before I pug it. 

I want to avoid trimming as much as possible. 

Thanks for the welcome. I missed being here and the friendships.  

[Min]

Okay so looking at the recipe the plastic materials are the C&C ball plus the bentonite. To make it less plastic I would reduce the C&C and increase the Grolleg. Grolleg contains more flux  and less silica than the ball clay though so I would use a glaze calc program like Glazy to rebalance those by reducing the spar and increasing the silica as necessary.  I'm guessing the body is quite sticky as it is now? 

A Val Cushing recipe that I have used and really liked is below. Julia Galloway uses it for ^6 soda firing, I used it in electric firing. Throws and fires well, fairly easy to throw big pieces with it. Fired colour is slightly off white. Most of the clay component is kaolin. I did find using bentonite added some very fine specs to the body, if you want to avoid this use Bentone MA (aka macaloid) instead of benonite (1/2 as much Bentone MA needed as compared to bentonite), it is very expensive though so there is a trade off between specs vs cost. If you have a clean white  bentonite it probably is fine.

C6 Clay Body – from Val Cushing:
EPK Kaolin 35
Tile 6 Kaolin 15
Nepheline Syenite 23
Flint 22
XX Sagger Ball Clay 5
Bentonite 3

[Marko]

39 minutes ago, Min said:

Okay so looking at the recipe the plastic materials are the C&C ball plus the bentonite. To make it less plastic I would reduce the C&C and increase the Grolleg. Grolleg contains more flux  and less silica than the ball clay though so I would use a glaze calc program like Glazy to rebalance those by reducing the spar and increasing the silica as necessary.  I'm guessing the body is quite sticky as it is now? 

A Val Cushing recipe that I have used and really liked is below. Julia Galloway uses it for ^6 soda firing, I used it in electric firing. Throws and fires well, fairly easy to throw big pieces with it. Fired colour is slightly off white. Most of the clay component is kaolin. I did find using bentonite added some very fine specs to the body, if you want to avoid this use Bentone MA (aka macaloid) instead of benonite (1/2 as much Bentone MA needed as compared to bentonite), it is very expensive though so there is a trade off between specs vs cost. If you have a clean white  bentonite it probably is fine.

C6 Clay Body – from Val Cushing:
EPK Kaolin 35
Tile 6 Kaolin 15
Nepheline Syenite 23
Flint 22
XX Sagger Ball Clay 5
Bentonite 3

Thanks Min, I will probably go with your suggestions and do a test. 

I will use Glazy and try to balance the recipe. I haven't ever done this, but I can learn. 

If I can't get it right, I'll try a small test batch of your recipe.

I have some VC plugged clay I made in August, so I will try it again.  Maybe some aging has helped.  

Thanks again. I hope you and yours are well and happy. 

You're a peach. ❤