How much resin for a set of 4 coasters?
Four 4 inch round coasters poured 3/8 inch deep need about 11.5 fluid ounces (340 milliliters) of mixed resin, including 10% extra — 2.61 fluid ounces per coaster, or about 2.86 oz each on a scale.
How to work it out
- π × (4 in ÷ 2)² × 3/8 in = 4.7 cu in = 2.61 fl oz each (≈ 2.86 oz on a kitchen scale)
- × 4 + 10% = 11.5 fl oz (≈ 12.6 oz on a scale)
- Mix ratio 1 : 1 by volume, SG A 1.15 / B 0.95 (typical, not published by the maker — type your data sheet’s SGs for exact weights) → Part A 5.74 fl oz (6.89 oz) + Part B 5.74 fl oz (5.69 oz)
A set of four round coasters is the classic first resin project, and four-cavity silicone molds are one of the most common kits. At under 12 fl oz in total, the whole set comes out of one 16 fl oz resin kit, with a little left for a test cup or a small trinket mold.
Adjust for your project
More options: waste · ratio · SG A …
- Per coaster (no waste)
- 2.61 fl oz (77.2 ml)
- Per coaster on a kitchen scale (pour to this)
- 2.86 oz (81.1 g)
- Whole set by weight, incl. waste (kitchen scale)
- 12.6 oz (357 g)
- Kits to buy
- 1 kit
- When mixing — Part A (resin)
- 5.74 fl oz (170 ml)
- When mixing — Part B (hardener)
- 5.74 fl oz (170 ml)
- Part A by weight
- 6.89 oz (195 g)
- Part B by weight
- 5.69 oz (161 g)
- Left over from the last kit
- 4.51 fl oz (133 ml)
- What to buy: 1 × 16 fl oz casting resin kit. Each kit has both bottles (resin + hardener) — you don’t buy them separately. Looking at a different kit size? Change Kit size above.
- At this depth, use a casting resin whose label covers it — coating (art) resins are made to go on only about 1/8 in (3 mm) per layer.
Resin by pour depth (four 4 in round coasters)
| Pour depth | Per coaster (no waste) | Casting resin to buy (whole set) | Kits to buy |
|---|---|---|---|
| 1/4 in | 1.74 fl oz | 7.66 fl oz | 1 kit |
| 3/8 in | 2.61 fl oz | 11.5 fl oz | 1 kit |
| 1/2 in | 3.48 fl oz | 15.3 fl oz | 1 kit |
What to know about a set of 4 resin coasters
Kit fit first: a 16 fl oz kit covers the set with about 4.5 fl oz left over — handy for a colour test before you commit, not enough for a second set. A 32 fl oz kit does two sets of four (about 23 fl oz with 10% extra) with roughly 9 fl oz to spare. Going to 1/2 in deep uses almost all of a 16 fl oz kit (the table shows it), so buy the bigger kit if you like thick coasters.
Depth decides the resin. At 3/8 in, a coating resin that levels in 1/8 in layers means three pours, waiting each time for the last layer to thicken to a soft gel. A casting resin rated for 3/8 in or more fills each cavity in one go, which is why many coaster kits ship with one. Whichever you use, pour all four from one cup so the colour and cure match.
Pour to weight: each coaster takes about 81 g (2.86 oz) of mixed resin. Put the empty mold on the scale, zero it, and fill each cavity to that number rather than to the brim — a brim-full cavity sheds resin over the edge as soon as you torch it.
The most common mistake is measuring the outside of the mold. A “4 inch” mold often means the outside of the silicone, and the cavity can be noticeably smaller; at 3.5 in across the set needs about 8.8 fl oz instead of 11.5 (see below). Measure the cavity itself.
For squares or hexagons, see how much resin for 6 square coasters and how much resin for 6 hexagon coasters.
Different size? Use the full Coaster Resin Calculator.
What you’ll need
- Silicone coaster & tray moldsBudget price
Flexible molds release cured resin without mold release. Measure the inside to calculate volume.
See options on Amazon (opens in a new tab) - Casting resin for molds & coastersMid-range price
Thinner and slower than coating resin, so it fills mold detail and handles thicker pours — check the label’s maximum depth.
See options on Amazon (opens in a new tab) - Digital scale (0.1 g)Budget price
For mixing by weight. Far more accurate than cup lines for small batches — and it doubles for the water method on molds.
See options on Amazon (opens in a new tab)
As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.
Frequently asked questions
How much resin for 4 coasters poured 1/4 inch thick?
About 7.66 fluid ounces with 10% extra — 1.74 fl oz per coaster, poured in one go with a casting resin.
How much resin for 4 round coasters 3.5 inches across?
About 8.8 fluid ounces at 3/8 inch deep with 10% extra — 2 fl oz per coaster, or about 2.19 oz each on a scale.
Other common sizes
- How much resin for 6 square coasters — 14.6 fl oz
- How much resin for 6 hexagon coasters — 457 ml
Sources
- ArtResin — How thick can you pour epoxy? (opens in a new tab) — Pour in layers of about 1/8 in; wet-on-wet after about 3–5 hours at the gel stage, or after a full cure
- ArtResin — FAQ (opens in a new tab) — Heat tolerance of cured resin (about 120°F); working time and temperature
- Epoxyworks — Controlling exotherm (opens in a new tab) — Thick masses of epoxy trap heat; large castings can overheat and crack