A gunmetal glaze I have wanted for decades!
After 40+ years of making pottery I finally have a perfect gunmetal black. It has an incredible silky surface. It does not cutlery mark. It does not craze
on anything. It is easy to clean. This is G2934Y
with 6% Mason 6600 black stain firing using the PLC6DS
schedule. I had to tune it a bit, adding about 15% glossy G2926B
, because it was a little too matte on initial firings. But now it is perfect. These are heavy mugs made using the M340
casting recipe (and the casting-jiggering
process). The speckled mug was made by casting a thin layer of the speckled version of the slip first, then filling the mold with the regular slip. I used a 40-minute cast to get walls nice and thick!
Context: Cooling rate drastically affects the appearance of this glaze, Gunmetal glaze
Sunday 2nd February 2020
Red burning, customer-found terra cotta clays tested
We tested four different clays (brought in by customers). One is from BC and three from Alberta. These fired sample bars show rich color, low soluble salts
and high density and strength at very low temperatures. L4233 (left): Cone 06 to 3 (bottom to top). Reaches stoneware-density at cone 02 (middle bar). Plasticity
is very low (drying shrinkage is only 4.5%). But, it is stable even if over-fired. L4254 (center bottom): Cone 04,02,3,4 (bottom to top). Very fine particled but contains an organic that is gassing and bloating the middle two bars. L4243: Fires lighter and looks stable here (cone 02,01,1,2 shown) but melts suddenly less than a cone above the top bar (well before vitrification
is reached). L4242 (right): Hyper-plastic (12% drying shrinkage!). Already melting by cone 02 (third from top). Achieves almost zero porosity
(porcelain density) at cone 04 (#2 bar). Even when mixed with 20% kaolin and 20% silica it still hits zero porosity
by cone 1. What next? I'll mix L4233 (left) and L4242 (right), that should produce stoneware density at cone 02 (about 1% porosity).
Context: Terra cotta, Soluble Salts, Drying Shrinkage, Vitrification, Bloating
Saturday 1st February 2020
New dealer showroom clay sample boards almost ready (not available retail)
We have new boards for high temperature oxidation and reduction, medium temperature and low temperature. These feature QRCodes for each of the bodies (they go to the information pages for that product on our website, these pages are getting more and more detailed with how-to information). Each body is shown with two glazes. Those glazes have QRCodes at the bottom that will take you to a page with everything you need to know about how to use and get or mix them.
Friday 20th December 2019
Hand-tooling a mug model vs. 3D-printing a mold to cast it
I am creating molds for a 2019 casting-jiggering
project to reproduce heavy stoneware mugs manufactured here 50 years ago. I have a profile drawing I want to match (upper left). The solid plaster model on the left was my first attempt at manual tooling. The metal template was time-consuming to hand-make, its contour was difficult-to-match to the drawing and the plaster surface turned out rough and difficult-to-smooth. To make the plaster model on the right I printed a shell (using my 3D printer
), poured the plaster in, extracted it after set and then smoothed it on the wheel using a metal rib and trimming tool. It matches the drawing perfectly and the round is very true. 3D-printing
is revolutionary for this type of thing! The drawings: I hired someone on Upwork.com to make them for me (using Fusion 360
). The shell-mold (to cast the model) on the upper right: I printed that too, in two pieces.
Context: 3D-Printing, Casting-Jiggering, 2019 Jiggering-Casting Project
Friday 13th December 2019
Cooling rate drastically affects the appearance of this glaze
This is G2934Y
satin matte with Mason 6600 black stain. The piece on the left was fired using a slow-cool firing schedule (C6DHSC
). The schedule for the one on the right turned the kiln off at 2100F (after a half hour drop-from-2200F-and-hold), then it free-fell. The slow cool gives the glaze on the left time to crystallize, thus it is now a stony matte (rather than a satin matte). It is interesting that to this mix of the glaze I added 20% glossy clear, yet it still matted on the slow cool.
Context: G2934Y - Cone 6 Magnesia Matte Low LOI Version, A gunmetal glaze I have wanted for decades!, Matte Glaze
Tuesday 26th November 2019
What we see in the park beside the Plainsman plant
The Plainsman Clays factory is right beside a baseball park. A beautiful place in the summer where children play and teams compete. But in the afternoon and evenings the deer move in. And mow the grass! The deer stay around all winter, in this residential area they are away from the coyotes and occasional mountain lion in the nearby river valleys.
Sunday 24th November 2019
This is how much casting slip 10,000 grams of powder makes
To-the-brim the bucket holds 8.8 liters (2.43 Canadian gal, 1.9 US gal). The slip itself weighs 14 kg (30 lb). It has a specific gravity
of between 1.75 and 1.8. The slurry was power-mixed in a larger bucket.
Context: Slip Casting, Deflocculation
Friday 22nd November 2019
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: Cobalt Oxide, GA6-C - Alberta Slip Rutile Blue Cone 6
Wednesday 20th November 2019
G2934Y glaze on Standard #112 body at cone 6
Produces an appearance very similar to dolomite-matte-glazed ware fired in cone 10 reduction. The effect would be similar using speckled bodies made by other manufacturers. Pieces made by Tom Friedman.
Context: G2934Y - Cone 6 Magnesia Matte Low LOI Version
Thursday 7th November 2019
Find thousands more like the following: Use the search field at the top of the page at the Digitalfire Reference Library.