Introduction
If you’re a ceramic artist looking to experiment with glaze colors, it’s essential to have a solid testing process in place. This guide walks you through the steps to create tiles, prepare glazes, and test different colorants such as oxides and stains to find your perfect finish. Whether you’re a professional potter or a hobbyist, mastering glaze color testing can help you achieve consistent, vibrant results.
Materials Needed for Glaze Color Testing
Before you begin, gather the necessary materials for testing glazes on porcelain tiles.
Materials to Create Tiles:
- Porcelain clay
- 75 1″ x 3″ x 1″ tiles
- 4 “T” stands
- Deli cups (one for each stain or oxide)
- Immersion blender
- NIOSH-approved respirator (for safety)
Colorants for Glaze Testing:
- Cobalt Carbonate
- Chrome Oxide
- Copper Carbonate
- Red Iron Oxide
- Manganese Dioxide
- Nickel Oxide
- Titanium Dioxide
- Silicon Carbide
- Various Stains
How to Make the Test Tiles
Step 1: Prepare the Slabs
- Purchase porcelain clay and roll it into a 1-inch-thick slab.
- Cut the slab into 75 tiles, each measuring 1″ x 3″ x 1″.
- Bisque fire the tiles to prepare them for glaze application.
Step 2: Make “T” Stands
Create stands to hold the tiles upright during glaze testing.
- Roll out four slabs of porcelain, each 10″ long by 4″ wide.
- Roll another set of four slabs, 10″ long by 5.5″ wide.
- In the middle of the 5.5″ x 10″ slab, score and slip it, then attach the 4″ wide slab upright.
- Create 8 coils, each 10″ long, and slip and score them to the base of the larger slabs.
- Bisque fire the “T” stands.
Glaze Mixing Instructions
Before applying the glazes, it’s essential to mix them accurately for each colorant.
Step 1: Label Your Test Tiles
- Count the number of different colorants you’ll test.
- Multiply that number by two (for duplicate tests) and label each test tile with a number using the Black Mayco Designer Liner.
Step 2: Select and Mix Base Glaze
- Choose a base glaze without any colorant.
- Mix 100 grams of the base glaze for each colorant or oxide you plan to test, adding an extra 100 grams for safety. For example, if you are testing 15 colorants, prepare a 1600-gram batch (1500 grams for the test, 100 grams extra).
Step 3: Water-to-Dry Ingredient Ratio
- Weigh the appropriate amount of water and pour it into a separate bucket.
- Slowly add the dry glaze ingredients to the water.
- Sieve the mixture back into the bucket to ensure smooth consistency.
For example: If you add 60 grams of water for every 100 grams of dry glaze, and you’re testing 15 colorants, you’ll need to mix 900 grams (or milliliters) of water for 1500 grams of dry ingredients.
Step 4: Measure and Distribute Wet Glaze
- Using the calculated water-to-dry ratio, measure the wet glaze into deli cups. For example, if you added 60 grams of water per 100 grams of glaze, you’ll need to add 160 grams of wet glaze to each deli cup.
Testing the Colorants
Step 1: Add Oxides or Stains
- Measure out the oxides or stains based on your glaze test requirements. You’ll only need up to 15 grams of each colorant.
- Thoroughly mix the oxides or stains into the deli cups containing the wet glaze.
Step 2: Apply the Glaze
- Hold the tile between your index finger and thumb. Dip the test tile into the deli cup to apply the glaze evenly.
- Repeat the process with the second set of tiles using a different amount of colorant, as indicated by your test plan.
Final Thoughts on Glaze Testing
Testing glazes is an essential process for achieving consistent and beautiful results in ceramics. By following these steps, you can efficiently test a wide range of oxides, stains, and colorants on porcelain tiles, ensuring your final pottery pieces are glazed to perfection.
Additional Tips for Successful Glaze Testing
- Wear Proper Safety Gear: Always wear a NIOSH-approved respirator when working with powdered oxides and stains to avoid inhaling harmful particles.
- Document Results: Keep detailed notes on the glaze recipe, firing schedule, and results for each colorant. This will help you replicate successful outcomes.
- Experiment Gradually: Start with smaller batches to avoid wasting materials and gradually scale up once you’ve achieved the desired results.
By optimizing your glaze testing process, you’ll be able to explore a wide range of color variations, leading to more creative and visually stunning ceramic pieces.
| Cobalt Carbonate .5g | Chrome Oxide 5g | Copper Carb 1g | Red Iron Oxide 3g | Manganese Dioxide 1g | Nickle Oxide 1 g | Titanium Dioxide 3g | Silicon Carbide 3g | Stain 5g | ||
| Cobalt Carbonate 2% (+1.5) | Chrome Ox 2% (+1.5) | Copper Carb 4% (+3) | Red Iron Oxide 9% (+6) | Manganese Dioxide 4% (+3) | Nickle Oxide 4% (+3) | Titanium Dioxide 9% (+6) | Silicon Carbide 9% (+6) | Stain 10% (+5) |
“This page contains affiliate links. As an Amazon Associate, I earn from qualifying purchases. If you choose to purchase after clicking a link, I may receive a small commission at no extra cost to you.”