Slip cast adjustment suggestions

[Harriet15]

I’m looking to use the recipe for casting slip below that will include Mason stains to color the clay. I really like the slip but it doesn’t take color that well and I’m wondering if I can adjust it, maybe with a grolleg kaolin instead of the EPK or a whiter ball clay? My thinking is to make it whiter but I’m guessing. Any advice would be very welcome! This is cone 7

OM4 25%
EPK  18%
Tile 6 5%
Neph sy 35%
Custer 9%
Frit3110 1%
Flint 7%

[Min]

Hi Harriet and welcome to the forum!

Which Mason stains and at what percentage have you tried? We’re they body stains? 

[Jeff Longtin]

Having tested several combinations, over the last year, I'll offer this:

Mason suggests using "body stains" at 5%. After much trial and much error I find this to be a good percentage across the board.  This doesn't give you the greatest color saturation but it leaves you with color and a USABLE body. 

I found that using a slip, soon after mixing the colors into it, resulted in a decent workable slip BUT it wasn't until I let the slip sit a week or two that the higher percentages really showed their negative side affects.  Most of the stains, at higher percentages, resulted in the slip gelling. You can add more water to counter it...but that just creates other problems.

 

 

 

[Harriet15]

Hi Min and Jeff, thanks for your replies! I’m using stains a lot in an earthenware body and previously in bone china with great results and so my question is more about the recipe for the slip than the stains. I really like this casting slip but think it probably needs to be whiter to really get the best color but wanted suggestions. 

[Min]

If you want it whiter then I would get rid of the ball clay altogether and use a porcelain slip using kaolin(s). I don't do a lot of slip casting but I use 1/2 Grolleg and 1/2 EPK for the clay part of my recipe. I use gray, black and taupe stains with it and the slip takes them well.