How Much Epoxy for Jewelry? (Pendants, Cabochons and Bezels)
Updated 2026-10-26
Jewelry pours are tiny - often 1 to 10 ml per piece - so the usual gallon tables are the wrong scale. What matters is the volume of each cavity (bezel, silicone mold or cabochon dome), how many pieces you cast in one session, and a generous waste allowance because cup and stick residue eats a large share of a small batch.
Use the mold volume calculator after measuring a cavity with the water method, or the epoxy resin calculator for simple cylinder and rectangle shapes. For coaster-scale pieces see how much resin for coasters.
The formulas
Cylinder / round cabochon: V (in3) = pi x (diameter / 2)^2 x depth
Bezel (approx rectangle): V = length x width x fill depth
ml = in3 x 16.387 Fl oz = in3 / 1.8047
Or measure: grams of water is about ml of volume
Jewelry molds are rarely perfect cylinders. When the shape is irregular, fill with water, weigh in grams (about ml), dry completely, then use that measured volume. Full steps: measure mold volume with the water method.
Typical jewelry volumes
| Piece | Approx volume | Fl oz | ml |
|---|---|---|---|
| 12 mm round cabochon, 3 mm deep | 0.021 in3 | 0.012 | 0.34 |
| 25 mm round cabochon, 5 mm deep | 0.150 in3 | 0.083 | 2.45 |
| 30 x 40 mm oval bezel, 2 mm fill | 0.146 in3 | 0.081 | 2.40 |
| 1 in round pendant mold, 1/4 in thick | 0.196 in3 | 0.109 | 3.22 |
| Small earring pair (2 x 1 ml) | - | 0.068 | 2.0 |
Individual pieces use almost nothing. A full curing session of 10-20 pendants is where the batch size becomes meaningful.
Worked example: 12 pendant molds
- Each mold holds about 3.2 ml (a 1 inch round, 1/4 inch deep cavity is about 3.22 ml).
- Twelve pieces: 3.22 x 12 = 38.6 ml.
- Convert: 38.6 / 29.5735 is about 1.31 fl oz (or 38.6 x 0.061024 is about 2.36 in3; 2.36 / 1.8047 is about 1.31 fl oz).
- Small-batch waste 20%: 1.31 x 1.20 is about 1.57 fl oz (about 46 ml).
- 1:1 epoxy by volume: about 0.79 fl oz A + 0.79 fl oz B. 2:1 by volume: about 1.05 fl oz A + 0.52 fl oz B.
Many jewelry resins list a minimum mix amount so the ratio stays accurate. If your kit says "do not mix less than 20 ml," mix at least that much even if the molds need less - leftover can fill a scrap mold rather than throw off the stoichiometry.
Why waste percent is higher for jewelry
On a gallon tabletop pour, 10% waste is often enough. On a 40 ml jewelry batch, the film left in a mixing cup and on a stick can be 5-10 ml by itself. Planning 15-25% extra for tiny pours is normal. Related discussion of waste allowances: epoxy waste percentage: how much extra to mix.
Inclusions and open bezels
Dried flowers, foil flakes, stone chips and wood slices displace resin. If an inclusion fills roughly one-third of a bezel's depth, resin volume drops by about that fraction - but you still need enough liquid to wet and cover the inclusion. Calculate the empty cavity first, then treat displaced volume as a buffer rather than reducing the mix below what you can reliably ratio.
Cure and demold notes
Thin jewelry pieces cool quickly and may take longer to reach demold hardness than a thick casting in the same room. Follow the TDS for demold time and temperature; a general overview is in epoxy cure time and temperature. Always work with ventilation and PPE per the product SDS.
Weighing vs volume for tiny batches
Kitchen measuring spoons are inaccurate under 5 ml. A digital scale that reads 0.01 g is usually more reliable for jewelry. Convert your target milliliters to grams using the product density from the TDS (many epoxies are near 1.05-1.15 g/ml; do not assume 1.0 unless the TDS says so):
Mass (g) = volume (ml) x density (g/ml)
Then split mass by the TDS weight ratio for Part A and Part B
Example: 46 ml total at density 1.10 g/ml = 50.6 g mixed. At a 1:1 by weight ratio that is 25.3 g A + 25.3 g B. At 100:45 by weight, A = 50.6 x 100/145 is about 34.9 g and B is about 15.7 g. Details: mix ratio volume vs weight.
Doming bezels without a mold volume
Open bezels are filled until the resin domes slightly above the rim. A practical estimate is bezel opening area x fill height to the rim, plus 10-20% for the dome. Example: a 20 x 20 mm square bezel filled 2 mm to the rim: 2.0 cm x 2.0 cm x 0.2 cm = 0.8 ml, plus 15% dome = about 0.92 ml per piece.
Batch planning worksheet
- List each mold or bezel and its measured ml.
- Sum the cavities for this session.
- Multiply by 1.15-1.25 for waste.
- Raise to the kit's minimum mix size if needed.
- Split A/B by ratio; write both masses on the cup before you pour.
Coverage context for larger crafts: epoxy coverage per gallon. Bubble tips for clear jewelry: how to fix epoxy bubbles.
Summary
Most single jewelry cavities hold 0.3-3 ml. Multiply by piece count, add 15-25% for small-batch waste, respect any minimum mix size on the TDS, and split Part A/B by the kit's stated ratio. Measure odd molds with water rather than guessing.