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Alberta Slip:Ravenscrag Cone 10R Celadon

Code: GR10-E
Modification Date: 2016-09-30 22:49:24
Member of Group: RV10 AS10

A celadon recipe containing only two ingredients. It affords slurry and drying control because proportions of raw and calcined materials can be varied.

MaterialAmount
Alberta Slip47.5
Ravenscrag Slip47.5
Ferro Frit 31345.0
 100.00  

Notes

This is a celadon that you can tune to your needs. It works well on dark and light stonewares and porcelains. Adjust the proportions of Alberta Slip to Ravenscrag Slip to fine tune the color (more Ravenscrag for lighter color). Adjust the amount of frit to tune the amount of gloss and melt fluidity. Calcium carbonate also works, but may produce more bubbles floating in the matrix. If you fire to cone 11, then no flux may be needed.

You can fine tune the thermal expansion (e.g. frit 3134 for higher expansion, 3249 for lower, 3124 for nuetral).

Since this glaze is 90% clay, you will need to calcine half of the Alberta Slip complement to reduce the drying shrinkage if it will be applied to dry or bisque ware (if applied to leather hard ware it could be OK as is).

Ravenscrag GR10-E celadon glaze

Ravenscrag GR10-E celadon glaze

(50:50 Ravenscrag Slip:Alberta Slip) at cone 10R on porcelain (right) and stoneware (left).

GR10-E Ravenscrag:Alberta Slip with 10% calcium carbonate

GR10-E Ravenscrag:Alberta Slip with 10% calcium carbonate

At cone 10R this produces an overly melted glaze. It also crazes.

GR10-E 50:50 Alberta Slip:Ravenscrag Slip celadon at cone 10R

GR10-E 50:50 Alberta Slip:Ravenscrag Slip celadon at cone 10R

On a white stoneware and a porcelain. The glaze is transparent, it has depth and varies in shade according to thickness, breaking to a much lighter shade on the edges of contours.

Ravenscrag Celadon and silky matte glazed mug by Tony Hansen

Ravenscrag Celadon and silky matte glazed mug by Tony Hansen

The outside glaze on this cone 10R mug (made of Plainsman H550) is simply an Alberta Slip:Ravenscrag Slip 50:50 mix with 5% added Ferro Frit 3134 (the Alberta Slip is calcined). This produces a stunning celadon with great working and application properties. Inside glaze: Ravenscrag Slip 90%, talc 10% (a matte having an extra ordinary silky texture). Learn more at ravenscrag.com.

Calcining Alberta Slip

Calcining Alberta Slip

Calcined Alberta Slip (right) and raw powder (left). These are just 5 inch cast bowls, I fire them to cone 020 and hold it for 30 minutes. Why calcine? Because for glazes having 50% or more Alberta Slip, cracking on drying can occur, especially if it is applied thick (Alberta Slip is a clay, it shrinks). I mix 50:50 raw:calcine for use in recipes. However, Alberta Slip has an LOI of 9%, so I need to use 9% less of the calcine powder (just multiply the amount by 0.91). Suppose, I needed 1000 grams: I would use 500 raw and 500*.91=455.


By Tony Hansen

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