Greenbarn Potter's Supply Ltd.

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Normal Hours of Operation

Open Mo-Fr 8:30-5PM, closed Sat, Sun and long weekends.

Next closure for stat holiday is for Victoria Day, closed on May 20, and re-open on May 21.





Ordering Information


Plainsman Products


  Low Temperature Clays
  Medium Temperature Clays
  High Temperature Clays
  Other Clays
  Native Clays
  Casting Slips


  Dry Materials
  Encapsulated Stains


  Spectrum Opaque Gloss Low Fire Glazes
  Spectrum Semi-Transparent Low Fire Glazes
  Spectrum Satin Matte Low Fire Glazes
  Spectrum Crackle Glazes
  Spectrum Metallic Glazes
  Spectrum Raku Glazes
  Plainsman Dry Glazes
  Potter's Choice Cone 5/6 Glazes
  Celadon Cone 5/6 Glazes
  Moroccan Sand Glazes
  Spectrum Hi Fire Cone 6 Glazes
  Spectrum Shino Glazes Cone 6
  Spectrum Celadon Glazes Cone 6
  Liquid Brights


  Spectrum 500 Underglazes
  Underglaze Tools
  Amaco Velvet Underglazes


  Enamelling Supplies
  Enamelling Tools


  Electric Pottery Kilns
  Electric Glass Kilns
  Kiln Furniture
  Kiln Parts, Accessories
  Exhaust Systems
  Potter's Wheels
  Slab Rollers
  Hand Extruders
  Banding Wheels
  Air Brushes


  Throwing Tools
  Trimming, Turning, Cutting Tools
  Wood/Bamboo Tools
  Wire and Wood Tools
  Decorating Tools
  Glazing Tools
  Ribs & Scrapers
  Ribbon/Wire Tools
  Knives, Needle Tools, Cutters
  Sculpture Tools
  Tool Kits


  Miscellaneous Accesories
  Cork Pads
  Oil Lamp Accessories
  Dispenser Pumps
  Teapot Handles
  Bisque Tiles

Western Canada's largest distributor of pottery materials and supplies. Clays, raw materials, tools, wheels, kilns, slabrollers, books & much more.

Our continuing goal is to supply artists, potters and crafts people with great quality products, knowledge and customer service. Our staff is familiar with all the items we stock and can help you through the selection and ordering process. We will also see that your order is shipped according to your directions, or put together for pick up at our retail store in Surrey, BC.

Kilns for Sale at 60% off - oddballs need good homes!

The following two kilns are in stock, brand new in the box, and are now discounted until each are sold!

1. Skutt Scarab, Flameworking Glass Kiln, 27x16x12" inside, 240volt/1phase. $8335 reg.

- now on sale at 60% less. $3334 + tax

2. Skutt Scarab Mini, Flameworking Glass Kiln, 12x16x12" inside, 240volt/1phase. $6055 reg.

- now on sale at 60% less. $2422 + tax

Sculpture Materials on Sale!

The following items are now discounted while stock remains!

1. Roma Plastilina, Grey/Green, oil based clay, offered in soft/med/firm

- now at 25% discount. Sale priced at $19.19/2Lb block + tax

2. Armature Wire (not intended for firing within a kiln):

- 1/16" by 32' roll: now at 25% discount. Sale priced at $6.19/roll + tax

- 3/16" by 10' roll: now at 25% discount. Sale priced at $11.49/roll + tax

- 3/8" by 10' roll: now at 25% discount. Sale priced at $17.89/roll + tax

Technical Tips Blog

At what point is a self-supporting cone bent to the correct degree?

A self supporting cone in an Orton guide

Orton says “90 angular degrees is considered the endpoint of cone bending”. First, let's assume the normal: Examination of cones on kiln-opening to verify controller operation. Consider the cone on the left: The tip is touching. But it is also beginning to buckle, which means it was touching for a while before the firing ended. Who knows how long! The second one is not touching but has still fallen a little too far. Why do we say that? The third one, positioned on the Orton guide, has reached the recommended 90 degrees. This demonstrates a good reason why self-supporting cones are much better than standard ones: They are not touching when considered done. And standard cones, when sent in a 3/4" plaque, have a less consistent bending behaviour.

Context: The bending of an.., Cones bending badly, Are you using your.., Manually programming a Bartlett.., What temperature do Orton.., Program your firings manually.., Cones bending theoretically cones.., Pyrometric Cone, Make Your Own Pyrometric..

Saturday 20th April 2024

What causes a clay to split after throwing like this?

Splitting during throwing

These cracks have been drawn because we were unable to get this to happen in our studio - likely because one condition was not met. This is M340, it is made from minimally processed natural mined clay. While inherently very fine it does have some sand particles. Consider the combination of conditions we created to try to make this happen:
-An unstable bowl shape (flared out to the edge of the clay's ability to support itself).
-Cutting the rim off with a needle tool and leaving that flat surface uncompressed and with water on it.
-Applying slip just after throwing the piece (rather than waiting until leather-hard).
-Not wedging the clay (or wedging it well).
Had all these been true and the clay was also soft and thrown using a lot of water (rather than slip) it could have split. Clays made from 200 mesh industrial minerals can even endure all of that. But to make this very unlikely just do the opposite of the above: Stable shapes, thrown rims, slipping later, wedging well and stiffness matching the shape being made.

Monday 15th April 2024

First mug in my newly created mold

Slip cast mug

This test mold is thin-walled yet I can cast three thick-walled mugs in three hours. This clay is L2596G, a buff burning cone 10 stoneware - the mug on the lower right has been fired to cone 10 oxidation. Achieving 4-5mm thick walls is not a problem if the casting slip employs a large particle kaolin intended for this purpose (e.g. Opticast). The flared lip works as expected, keeping the rim nice and round. No cracks have appeared at handle joins, even for pieces left in the mold overnight. The mold halves mate with each other very well and the seam is easy to remove. The seam on the base is an issue - I have to be careful to line up the halves well before clamping the mold strap - this is a warning for accuracy during the mold production stage. And the possible motive for a three-piece mold.

Context: AI-imagined mug I chose.., Coffee Mug Slip Casting..

Wednesday 10th April 2024

3D printed plaster filled case mold ready for pouring block mold

3D printed mug mold

This is part of a project to make a slip-casting mold for a coffee mug. In the slicer, I split the print into two pieces 22mm up from the base. This enabled doing the bottom section right side up and the top one upside down. That drastically cut the amount of support generated (and thus printing time). I scotch-taped the two halves together and filled it with plaster to produce a rigid block mold. The two halves fit so precisely it is difficult to tell where they join. The big benefit of printing it upright like this is that the all-important front face is very flat (there is some warpage on other parts but that does not matter).

Context: Coffee Mug Slip Casting..

Wednesday 20th March 2024

A better cone 6 oatmeal glaze using Ravenscrag Slip

Ravenscrag oatmeal glazed mug

Left: G3933EF oatmeal based on Ravenscrag Slip.
Right: G3933 oatmeal based on a mix of G2934 matte and G2926B glossy base glazes.
Both have the same added colorants. The Ravenscrag version features several advantages. Most importantly much less tendency to crawl. It has better application properties, the slurry needs less water and it is naturally thixotropic. It has an extra option for adjusting properties: Changing the ratio of roast-to-raw Ravenscrag clay. It is responsive to cooling differences - more matte on slow cool versions of the C6DHSC schedule (e.g. 150F/hr), more glossy on faster cools (e.g. 250F/hr). And, its recipe is adjustable (e.g. raising the MgO if a more persistent matte is needed). And, it looks and feels way better, interacting with dark bodies for richer color and varying in tone more for thinner and thicker sections.

Context: Ravenscrag Slip, Sometimes it is better..

Wednesday 13th March 2024

Use the same runny glaze as its own catch glaze

As runny glaze as its own catcher

This is G3948A, a super runny cone 6 iron red glaze. The clay body is M340. This glaze has to be runny, applied thickly enough, be held at temperature and cooled slowly to achieve this visual effect. When applied at the needed thickness it will run off the ware onto the kiln shelf during firing. Why has that not happened? A catcher glaze on the lower section. In this case, the catcher is the same glaze. On the left, the bottom half of the mug has just been dipped into the glaze quickly, giving a layer that is too thin to achieve the red effect. That dried within a few seconds and enabled pushing the top half down into the dipping glaze for twice as long (the inside has a liner glaze and is waxed up to the rim). The upper section glaze is guaranteed to run and the bottom is not thick enough to run. The result is complete blurring of the dividing line and coverage that looks natural and flawless.

Context: Stop a runny glaze.., Catch Glaze

Tuesday 5th March 2024

Paint another layer onto a fired glaze? Yes. With CMC gum.

The cone 6 mug on the left has the G3933A glaze, applied as a dipping glaze. It turned out poorly - crawling from corners and looking thin and washed out. I made a brushing glaze version of this (which adds 1.5% CMC gum), I keep it around for this very purpose. It has a high specific gravity (unlike commercial ones that have high water contents - they will run and go on too thin if you try this). Because of the gum it dries hard, there is no shrinkage or cracking. On a second firing, using the C6DHSC schedule again, (mug on the right) the surface is transformed - thicker, more vibrant color (being picked up from the underlying body).

Context: CMC Gum, Six layers 85 Alberta.., Control gel using Veegum.., Convert a pint of..

Wednesday 28th February 2024

Iron red glaze fired at cones 6, 5 and 4

Iron red glaze at cone 6, 5, 4

These mugs are Plainsman Coffee Clay. The glaze on all three is G3948A iron red. They were fired at cone 6, 5 and 4 using the C6DHSC schedule (adjusted for top temperature). As can be seen, the red color depends on the melt fluidity achieved at cone 6.

Context: Same glaze on black.., Iron Red Glaze

Sunday 25th February 2024

Finished cast v1 stoneware beer bottles

Cast ceramic beer bottles

The center bottle is a standard glass one, the other two are ceramic, cast out of the version 1 plaster mold. The stopper fits perfectly. The clay is Plainsman M370 + 10% raw umber, it fires black. The glaze is GA6-B. They were fired using the C6DHSC firing schedule. The slightly larger size will enable inserts at the bases to inlay a logo or other info. These bottles are a testament to how 3D printing and 3D design now make it possible for even casual potters to make pieces never before practical or even possible.

Context: Slip cast leather-hard full-sized.., Ceramic beer bottles with.., Beer Bottle Master Mold..

Saturday 24th February 2024

The incredible plasticity of bentonite. It is the secret to win the ThrowDown!

Two dissected vases showing the comparison in wall thickness

The 20cm vase on the left is thrown from what I thought was a very plastic body, M370. I achieved close to the same thickness top-to-bottom (5mm). The one on the right was the same original height, 20cm. But it has dried down to only 18cm high, it shrinks 14% (vs. 6% for the other). The thinnest part of the wall is near the bottom, only 2mm thick! How is it possible to throw that thin? The body is 50% ball clay and 50% bentonite. Bentonite, by itself, cannot be mixed with water, but dry-blended with fine-particled ball clay it can. That bentonite is what produces this magic plasticity. But it comes at a cost. It took about four days to dewater the slurry on our plaster table. And one month under cloth and plastic to dry it without cracks.

Context: Bentonite, Drying Ceramics Without Cracks.., Plasticity

Friday 23rd February 2024

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Greenbarn Potter's Supply Ltd., 9548 - 192nd Street, SURREY, BC V4N 3R9
Phone: 604-888-3411, FAX: 604-888-4247, Email: