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 Easter Weekend, closed on Mar 29, 30, 31, April 1, and re-open on Apr 2.





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

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

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: First slip cast leather-hard.., Version 2 beer bottle.., 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

Coarse body fires with smoother glaze

Glaze fires better on coarse body

On the left is Plainsman M332, a sandy and coarse body dry ground at 42 mesh. On the right on a wet-processed body, sieved at 80 mesh and then filter pressed - it is porcelain smooth. Yet that glaze, GA6-C, on the smooth body is covered with blister remnants while the same glaze on the coarse body is glassy smooth (they were in the same firing). That smooth glaze is courtesy of the C6DHSC slow cool firing schedule. But why does it perform so poorly on the finer body? That body is being overfired. Pieces are warping. Although not bloating, it is beginning to decompose and generate gases, they are producing the blisters.

Context: Melt flow test demonstrates.., Glaze Blisters

Tuesday 20th February 2024

Control gel using Veegum, brushing properties with CMC gum

Mixing a brushing glaze

This is G1214Z1 brushing glaze (with 5% titanium added). For a 340g powder batch (to get a pint) my initial target is 5g CMC gum and 5g Veegum. CMC controls drying speed and Veegum the amount of gelling. I first mix the CMC with the powder and shake the whole batch in a plastic bag. Then I add it all to 440g of water in the blender jar and mix it well (making sure no agglomerates remain (stage 1). Stage 2 is adding the VeeGum slowly, while high-speed blender-mixing, this is important because it enables tuning the degree of gel (which cannot be predicted). Because this recipe has little clay, it took all 5g of Veegum without overgelling (the entire mass moved freely in the mixer jar). But it did gel overnight (so 4g would be better next time). By contrast, it is the brushing behavior that demonstrates whether the amount of CMC is right. Not enough and coats dry too fast and go on too thick. Too much and it dries too slowly and too many coats are needed.

Context: Veegum, CMC Gum, Here is my setup.., Paint another layer onto.., Micro Organisms, Rheology, Brushing Glaze

Sunday 11th February 2024

4-7% tin oxide in a clear glaze - is this better than Zircopax?

These samples illustrate 4, 5, 6 & 7% tin oxide added to a transparent. Tin is super expensive (Zircopax is five times less expensive at time of writing). But consider some advantages of tin. It creates a whiter glaze. A tin-opacified glaze may only need to be half as thick as a zircon-opacified one. Only half the percentage is required in recipes. Tin does not reduce the glaze's thermal expansion as much. On these samples, the higher percentages of tin seem to produce an even better glossy surface. Tin is less likely to cause crawling, a classic issue with high-zircon glazes (it impedes melt fluidity, that is what holds super thickly applied majolica glazes on the ware). Tin is the opposite; even though this recipe is high in strontium, and thus has a high surface tension, there is no indication of crawling with the tin addition. A final issue is cutlery marking, a common problem with zircon-opacified glazes. But not with tin oxide.

Context: Tin Oxide

Sunday 11th February 2024

This pottery glaze is not flaking off - the underglaze is.

Orange underglaze is flaking off

Pure ceramic stain powders don't melt at typical pottery temperatures so they cannot bond with clay body surfaces. They don't suspend in water and don't harden on drying. Pure stains contribute only one ceramic property: Color! Commercial underglazes sold in jars dilute stains into a recipe of materials, a 'base medium', designed to impart the missing properties. Unfortunately, consider a problem: Blue stains are fluxes and potent at low percentages. Orange stains (and others) are refractory and require much higher percentages. But for convenience underglaze manufacturers will want to use the same medium and percentage pigment to make an entire line of underglazes. That causes the problem seen here - flaking is happening at the interface between the body and orange underglaze. This underglaze recipe needs more frit (or a more potent one) so that enough melting occurs to create a better bond. For some colors it can thus be an advantage to make your own underglazes.

Context: Creating a Non-Glaze Ceramic.., An engobe is shivering.., Underglaze, Body glaze Interface

Sunday 11th February 2024

First slip cast leather-hard full-sized beer bottle!

Slip cast beer bottle

Left is our M370 + 10% raw umber, it is leather hard, just out of the mold. By the time it is fired it will be 12% smaller and will match the glass one. The pads are positioned firmly and correctly for the swing-top stoppers. The narrow neck can cause issues while draining the clay slurry from the mold, the flow creates suction that can pull the soft walls away from the mold face (a slower pour is thus needed). A large 3D printed pour spout is also needed to provide enough of a reservoir for the slurry during casting.

Context: Finished cast v1 stoneware.., Beer Bottle Master Mold..

Tuesday 6th February 2024

Here is why porcelain engobe does not fit stoneware

Porcelain engobe misfit on stoneware

This is how bad the fit can actually be. In the front is a bi-clay EBCT test strip of a grogged cone 10R sculpture clay sandwiched with a porcelain. After drying this bar was relatively straight. The back bar bent quite a bit even after bisque. But the bend on the front bar really shows the misfit. But this is not a thermal expansion issue where volume changes are measured in 100ths of a mm - these plastic bodies shrink 5-8% during firing, that is up to 8mm change in these 10cm long cars, that is the kind of volume change needed to make this happen. The porcelain has the higher fired shrinkage so it pulls the bar toward itself. The internal stress makes this bar a time bomb, waiting for a mechanical or thermal trigger to burst it into a hundred pieces. Admittedly, putting a thin layer of this porcelain onto a piece of heavy ware is not going to bend it - but the stresses of the porcelain being stretched-bonded will still be there, seeking relief (likely exhibited by cracking or flaking).

Context: Engobe Body Compatibility Test.., Absolutely jet-black cone 6.., Engobe

Monday 5th February 2024

Replace Custer Feldspar in a cone 10R glaze recipe in 2 minutes

Replacing custer feldspar for another in a glaze recipe

Our G2571A and G1947U cone 10R glaze recipes are both in use in Ecuador. One user has been importing Custer feldspar, but cannot get it and needs to substitute a local feldspar. That material is much higher in SiO2 and much lower in Al2O3 and KNaO (so a pound-for-pound substitution is not going to work). Here is how I used my account at to figure out what to do. It turned out to be a matter of increasing the new feldspar to match the KNaO matched (which also matched the Al2O3) and then reducing the silica to match the SiO2 match. The amount by which I had to change the feldspar is a testament to how different the chemistry of these materials can be from country to country.

Context: Custer Feldspar, Substituting Custer Feldspar for..

Thursday 1st 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: