Glaze Line Blend Calculator
Enter the two measured stock glaze batches and the percentage range you want to test. The calculator returns a cup-by-cup blend table, reserve-adjusted stock needs, and a check against the stock volume you prepared.
Stock required with reserveA: 72.6 mL; B: 72.6 mL
- Blend increment
- 10%
- Stock A required with reserve (mL)
- 72.6
- Stock B required with reserve (mL)
- 72.6
- Dry glaze A used (g)
- 55
- Dry glaze B used (g)
- 55
- Stock sufficiency
- Stock A has 47.4 mL remaining; Stock B has 47.4 mL remaining.
Test-cup mixing table
| Test | Glaze A % | Glaze B % | Stock A (mL) | Stock B (mL) | Total wet (mL) | Dry A (g) | Dry B (g) | Measuring note |
|---|---|---|---|---|---|---|---|---|
| 1 | 100% | 0% | 12 | 0 | 12 | 10 | 0 | |
| 2 | 90% | 10% | 10.8 | 1.2 | 12 | 9 | 1 | |
| 3 | 80% | 20% | 9.6 | 2.4 | 12 | 8 | 2 | |
| 4 | 70% | 30% | 8.4 | 3.6 | 12 | 7 | 3 | |
| 5 | 60% | 40% | 7.2 | 4.8 | 12 | 6 | 4 | |
| 6 | 50% | 50% | 6 | 6 | 12 | 5 | 5 | |
| 7 | 40% | 60% | 4.8 | 7.2 | 12 | 4 | 6 | |
| 8 | 30% | 70% | 3.6 | 8.4 | 12 | 3 | 7 | |
| 9 | 20% | 80% | 2.4 | 9.6 | 12 | 2 | 8 | |
| 10 | 10% | 90% | 1.2 | 10.8 | 12 | 1 | 9 | |
| 11 | 0% | 100% | 0 | 12 | 12 | 0 | 10 |
The table proportions are based on dry-solids mass, then converted to wet stock volume from each measured stock concentration.
How to use this calculator
- Prepare each stock glaze, then enter the dry recipe weight and measured final wet volume for each one.
- Choose the number of test cups and the dry glaze mass you want in each cup.
- Enter the first and last glaze B percentages; reversed ranges are allowed.
- Use the table to measure each cup while keeping both stocks fully suspended.
How the line blend is calculated
A glaze line blend mixes two endpoint glazes in a controlled series. The traditional volumetric method works cleanly when both stocks are made from the same dry weight and diluted to the same final volume. This calculator uses the same idea, but it calculates from the measured dry-solids concentration of each stock so the two wet volumes do not have to match.
Let n be the number of tests, m the dry glaze grams per cup, p0 and p1 the starting and ending glaze B percentages, WA and WB the dry weights used for the two stocks, VA and VB their final stock volumes, and r the reserve percentage.
cA = WA / VA and cB = WB / VB
f_i = (p0 + (p1 - p0) x i / (n - 1)) / 100
dA_i = m x (1 - f_i) and dB_i = m x f_i
vA_i = dA_i / cA and vB_i = dB_i / cB
The test table lists those values for every cup. The reserve-adjusted stock requirement is (1 + r / 100) times the sum of the cup volumes for that stock. The blend increment is the absolute difference between the first and last glaze B percentages divided by n - 1.
What moves the numbers most
The dry glaze per test scales every dry contribution and every stock volume. The prepared-stock concentration changes the wet amount needed to deliver a given dry mass: a thinner stock needs more milliliters, while a denser stock needs fewer. The endpoint percentages set the range; a 0% to 100% run includes pure A and pure B, while a narrower range omits one or both endpoints.
Equal wet volumes only produce equal dry proportions when the two stocks have the same dry grams per milliliter. If one stock was topped up to a different final volume, the calculator corrects each transfer so the dry recipe proportions remain the intended blend.
What this calculator leaves out
The table controls mixing proportions only. It does not predict fired color, melt, fit, durability, leaching, or food-contact suitability. Keep each stock stirred while measuring, because settling changes the dry solids delivered by a syringe or graduated cylinder. Test the blends on the clay body and firing schedule you actually plan to use.
Worked example
Suppose you want 11 cups, each with 10 g of dry glaze, from stock A and stock B that were each made from 100 g dry material and topped up to 120 mL. The concentration of each stock is 100 / 120 = 0.8333 g/mL. A 0% to 100% glaze B run gives a 10 percentage point increment.
Cup 1 is 100% A and 0% B, so it uses 10 / 0.8333 = 12.00 mL of stock A and no stock B. Cup 6 is 50% A and 50% B, so it uses 6.00 mL of each stock. Cup 11 is 0% A and 100% B, so it uses no stock A and 12.00 mL of stock B. Across the full series, the calculator sums 55.00 g dry A and 55.00 g dry B, or 66.00 mL of each stock before reserve. With a 10% reserve, each stock requirement is 72.60 mL.
Common questions
What is a glaze line blend?
A glaze line blend is a row of tests that mixes two endpoint glazes in changing proportions. It is useful when you want to see a gradual shift between two recipes, two colorant additions, or two versions of a base glaze.
Why do equal stock concentrations matter?
If both stocks contain the same dry grams per milliliter, equal wet volumes also represent equal dry recipe portions. If the stocks have different concentrations, equal wet volumes no longer equal equal dry mass. This calculator corrects the wet transfer volumes from the dry weight and final volume of each stock.
Can I omit the pure A and pure B endpoints?
Yes. Set the first and last glaze B percentages to the range you actually want to test, such as 20% to 80%. The number of cups is still spread evenly across that selected range.
How many steps should a line blend contain?
Eleven cups gives 10 percentage point steps across a full 0% to 100% blend and is a practical starting point. Use more cups when a small addition has a strong effect, or use a narrower percentage range after a first screening test.
Can I use commercial wet glazes?
Only if you know the dry-solids mass represented by a measured final volume of each glaze. Specific gravity alone is not enough to identify dry recipe concentration unless you also know the material density relationship for that exact glaze.
Why do the total wet volumes differ between cups?
The dry mass per cup is constant, but stock A and stock B may have different dry grams per milliliter. Cups with more of the thinner stock need more wet volume to deliver the same dry mass.