Oct 22, 2026: We are working on protecting our servers against the PHP2Shell vulnerability just discovered. The CDN download server is back online. The digitalfire and insight-live servers were patched on Oct 21.
At various thicknesses on M340, M370, P300. Fired at cone 6 oxidation using the C6PLST firing schedule.
For speckle add granular manganese (adjust the percentage to get the desired speckle density, start at 0.25%). Since the manganese particles are very heavy, and thus want to settle out, the glaze slurry should be thixotropic and stirred before each dip.

This picture has its own page with more detail, click here to see it.
The underglaze is the 20x5 cone 6 base transparent glaze (G1214M with 5% Mason 6666 black stain). Overglaze left: GR6-H Ravenscrag Oatmeal. Overglaze right: GA6-F Alberta Slip oatmeal. Both produce a pleasant silky matte texture. Double layering using typical dipping glazes is prone to crawling (because of shrinking and cracking during drying). By keeping layers fairly thin, it is possible to achieve success, but with glazes high in clay content (as these are), more is needed. A mix of raw and roasted Alberta and Ravenscrag Slips is the answer here. Start with a 50:50 ratio and adjust to establish a balance between drying hardness and drying shrinkage. For more assurance in production situations, mix the underlayer black as a base-coat dipping glaze.
There are enough variables that a record-keeping system is needed. Start now, and you won't regret it.

This picture has its own page with more detail, click here to see it.
The black recipe was made using G1214M with 5% Mason 6666 stain. The oatmeal overlayer is 50% the thickness of the black. The more fluid under-black comes through leaving islands and vertical rivulets of the stiffer oatmeal. Good control of the glazing process is needed to get consistent results using this approach.

This picture has its own page with more detail, click here to see it.
This is GR6-H Ravenscrag Slip oatmeal over G1214M black on porcelain at cone 6 oxidation to create an oil-spot effect. Both were dipped quickly.
| Recipes |
GR6-H - Ravenscrag Cone 6 Oatmeal Matte
Plainsman Cone 6 Ravenscrag Slip glaze. See more at ravenscrag.com. |
![]() PayPal | No tracking, No ads, No paywall, No transient content! Just organized, concise information constantly updated and improved. Was this helpful? Consider supporting me. |
Buy me a coffee and we can talk