A black engobe transforms the floating blue glaze over it
M340 stoneware fired to cone 6 (drop-and-hold schedule). The L3954B engobe fires deep black (it has 10% Mason 6600 black stain instead of the normal 10% Zircopax). It was applied inside and partway down the outside (a much less messy process than using a black clay body). They were bisque fired and glazed inside using the base GA6A Alberta Slip amber clear (using Frit 3195). The outside glaze is Alberta Slip Rutile Blue (you are seeing it on the bare buff body near the bottoms and over the black clay surface on the uppers). To learn more about how to make the engobe and start making black pots click "Product Data Sheets" at PlainsmanClays.com and go to the section on Medium Temperature.
Context: L3954B - White Cone 6 Engobe for Plainsman M390, M340, Cone 6 Drop-and-Soak Firing Schedule
Monday 2nd October 2017
Dark Umber-Stained Engobes on M340 at cone 6
This is the standard Plainsman L3954D white engobe recipe with the 10% Zircopax switched for Burnt Umber. The result is a dark, rich, ultra-gloss brown (almost black). The engobe is applied inside and half-way down the outside. The mug on the left is glazed inside and out with the base GA6A Alberta Slip cone 6 recipe (but uses Ferro Frit 3195 instead of 3134). The one on the right has the same glaze on the outside but the G2926B clear transparent on the inside (it is micro-bubbling). This engobe works even better with a black stain.
Context: L3954B - White Cone 6 Engobe for Plainsman M390, M340, GA6-A - Alberta Slip Cone 6 Amber Base Glaze
Monday 2nd October 2017
Making ceramic tile shapes by 3D printing your own cookie cutters
This was done on an affordable RepRap printer. The shapes were drawn in Illustrator, extruded in Fusion 360 and sliced and printed using Simplify3D (which took about 30 minutes each). The round wooden block was used to press them into the clay. The plastic wrap made sticking a non issue (and rounds the corners nicely). The clay is a low fire, buff burning talc body (Plainsman L212). Commercial bottled glazes were applied by brushing (in three coats) after bisque. The tiles were fired at cone 03. This is an old classic design that I discovered when researching Damascus tile. The toughest obstacle was learning how to use Fusion 360. It turns out that cookie cutters are a starter project for many 3D software packages, there are lots of videos on making them.
Context: 3D Printing Ceramics
Wednesday 20th September 2017
Deep, deep blue without any cobalt. How?
These have to be seen to be believed, it is the deepest, richest blue we have ever produced. This is Plainsman M340 fired to cone 6. Black-firing L3954B engobe (having 10% Burnt (not raw) Umber instead of the normal 10% Zircopax) was applied inside and partway down the outsides (at the stiff leather hard stage). The incising was done after the engobe dried enough to be able to handle the piece. The glaze is Alberta Slip rutile blue. Firing schedule: Cone 6 drop-and-soak.
Context: GA6-C - Alberta Slip Rutile Blue Cone 6, Cone 6 Drop-and-Soak Firing Schedule
Wednesday 20th September 2017
Vintage boxes of Plainsman Clay found. From 1966!
M20 was for forerunner of M340. M22. We are not actually sure. Does anyone know? Would it still be good? Definitely. Just smash it up and put the dried pieces in a bucket of water to slake.
Tuesday 12th September 2017
Kiln wash that really works. How?
The shelf on the right in the traditional kaolin:silica kiln wash. Flaking constantly. Sticking on the feet of ware. A real aggravation. The one on the left: perfectly even. Yet thin. Much more refractory so it has not hardened or become brittle. Or cracked. And it paints on beautifully. The secret? Zircon. Zircopax, to be precise. Zircopax is among the most refractory materials in ceramics. We mixed it with some calcined, rather than raw kaolin. That greatly reduces drying and firing shrinkage and helps densify and stabilize the coverage (by its flat particle shape). Laguna gum solution was added to harden the dry layer and slow down the drying (their gum solution has a higher percentage of CMC than achievable using common mixing methods). Click the link below to get the recipe.
Context: Plainsman Super Kiln Wash, Kiln Wash
Thursday 7th September 2017
Common dipping glazes converted to jars of brushing glazes
These are cone 6 Alberta Slip recipes that have been brushed onto the outsides of these mugs (three coats). Recipes are GA6C Rutile Blue on the outside of the left mug, GA6F Alberta Slip Oatmeal on the outside of the center mug and GA6F Oatmeal over G2926B black on the outside of the right mug). One-pint jars were made using 500g of glaze powder, 75g of Laguna CMC gum solution (equivalent to 1 gram gum per 100 glaze powder) and 280g of water. Using a good mixer you can produce a silky smooth slurry of 1.6 specific gravity, it works just like the commercial bottled glazes. The presence of the gum makes it unnecessary to calcine the Alberta Slip.
Context: CMC Gum, Where Do I Start?, Brush-on commercial pottery glazes are perfect? Not quite!, Glaze Layering, Brushing Glazes
Thursday 7th September 2017
Polymer plates. Great for stamping into clay.
These are samples made by Boxcar Press. They make different depths, you need the 0.047 relief depth. While the others will press a crisp design into the clay, the shallow depth will make it difficult to avoid rubbing out the color from the recesses when you a sponging it off the top. Traditionally polymer plates have had metal backing and were expensive, but these are plastic and inexpensive. When designing them create a border around the outside of the design to contain it. This is needed because when the stamp is pressed hard into the clay, it smears away from all outer edges of the design, that containment-line keeps those edges clean. Also, they do not actually need to be stuck to a piece of wood, it is often better to lay them face down on the clay and use a wooden block and hammer to press them in to stiff clay. Use spray cooking oil as a parting agent if needed. They are flexible and peel off easily.
Context: Example of a logo done using a polymer plate
Thursday 17th August 2017