Monthly Tech-Tip | No tracking! No ads! |
Your studio or workshop can save a lot of money making and even selling your own glazes to students (at least for common colors and types). The supplies shown here enable printing quality labels on ordinary paper and applying them to jars that cost about $2. What about the glazes themselves? Just do what glaze companies do: Add stains to a base transparent glossy or matte glaze (for example G1916Q for cone 04 or G2926B for cone 6). Each 16oz jar needs 350g powder, 450g water, 5g CMC gum and 5g Veegum (leave out the Veegum and use less water for thicker coats). Stains are expensive (5-20 cents/gm here in 2024), at 7.5% (25g) that is $1-5 per jar. The materials for the G1916Q base cost $10/kg, and for G2926B $4/kg. Thus each jar costs $3.33 and $1.33 respectively. Making recipes of 5000g at a time would enable making 15 jars. A best-case is thus about $5/jar, worst case about $10/jar (compare that with commercials that are about $15-70). Of course, you can save money by looking for deals on materials and stains and recycling jars. Consider other advantages of making your own: You can tune the rheology, you know what is in it, you can adjust recipes to fit your clay bodies (to prevent crazing or shivering).
Are you worried about labelled, testing and SDSs? Take a look at ASTM D-4236 and see if you still need to worry.
To make a low SG version of G2934BL I have already weighed out a 340g batch (it contains 5g each of Veegum and CMC gum to gel the slurry and slow the drying). I use 440g of water initially (adjusting that according to experience in brushing behaviour). After shake-mixing all the powder in the plastic bag I pour it into the water on low speed and finish with 20 seconds on high speed. This produces a low specific gravity brushing glaze, it just fills this 500ml jar. In subsequent batches, I adjust the Veegum for more or less gel and the CMC for slower or faster drying. Later I also assess whether the CMC gum is being degraded by microbial attack - often evident if the slurry thins and loses its gel. Since each glaze recipe responds differently and changes differently over time, good notes are essential. We are working on dozens of these at any given time, each is code-numbered in our group account at Insight-live.com. This is so worthwhile doing that I make quality custom labels for each jar!
URLs |
https://www.uline.ca/BL_6409/3M-Label-Protection-Tape
3M Label Protection tape |
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URLs |
https://www.uline.ca/BL_7304/Label-Protection-Tape-Dispensers
3M Label Protection Dispenser |
URLs |
https://www.uline.ca/Product/Detail/S-14510/Jars/White-Round-Wide-Mouth-Plastic-Jars-16-oz-White-Cap
White 16oz 500ml plaster jars |
URLs |
https://plainsmanclays.com/store/index.php?find=stain&pictureflow=1&iframe=0
An example of ceramic stains sold at a supplier |
URLs |
https://www.astm.org/d4236-94r21.html
ASTM D-4236 - Standard Practice for Labeling Art Materials for Chronic Health Hazards - It is not what you think! |
Glossary |
Food Safe
Be skeptical of claims of food safety from potters who cannot explain or demonstrate why. Investigate the basis of manufacturer claims and labelling and the actual use to which their products are put. |
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