How much resin for 6 square coasters?
Six 4 inch square coasters poured 1/4 inch deep need about 14.6 fluid ounces (433 milliliters) of mixed resin, including 10% extra — 2.22 fluid ounces per coaster. One 16 fl oz kit covers the set with 1.37 fl oz to spare.
How to work it out
- 4 in × 4 in × 1/4 in = 4 cu in = 2.22 fl oz each (≈ 2.43 oz on a kitchen scale)
- × 6 + 10% = 14.6 fl oz (≈ 16 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 7.31 fl oz (8.77 oz) + Part B 7.31 fl oz (7.25 oz)
Square coasters hold about 27% more resin than round ones of the same width, because they keep the corners. Pouring them 1/4 in deep instead of 3/8 in claws most of that back, and a 1/4 in pour is within the single-layer limit of more resins.
Adjust for your project
More options: waste · ratio · SG A …
- Per coaster (no waste)
- 2.22 fl oz (65.5 ml)
- Per coaster on a kitchen scale (pour to this)
- 2.43 oz (68.8 g)
- Whole set by weight, incl. waste (kitchen scale)
- 16 oz (454 g)
- Kits to buy
- 1 kit
- When mixing — Part A (resin)
- 7.31 fl oz (216 ml)
- When mixing — Part B (hardener)
- 7.31 fl oz (216 ml)
- Part A by weight
- 8.77 oz (249 g)
- Part B by weight
- 7.25 oz (205 g)
- Left over from the last kit
- 1.37 fl oz (40.6 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.
- Tight fit: only 1.37 fl oz spare. Resin left in the cup and on the stir stick can use that up — buy one more kit if you’re adding pigment or want a test pour.
Resin by coaster width (six squares at 1/4 in)
| Square size | Per coaster (no waste) | Casting resin to buy (whole set) | Kits to buy |
|---|---|---|---|
| 3.5 in square | 1.7 fl oz | 11.2 fl oz | 1 kit |
| 4 in square | 2.22 fl oz | 14.6 fl oz | 1 kit |
| 4.5 in square | 2.81 fl oz | 18.5 fl oz | 2 kits |
What to know about 6 square coasters
Six is where one 16 fl oz kit gets tight. The set needs about 14.6 fl oz with 10% extra, which leaves only about 1.4 fl oz in the kit — the allowance is doing all the work. If you plan to test a colour first, add mica powder, or pour a seventh coaster “while you’re at it”, buy a 32 fl oz kit instead. Size matters just as much: at 4.5 in square the same six need about 18.5 fl oz, two 16 fl oz kits (table above).
Corners are the difficult part of a square mold. Bubbles collect in them and the resin can stop short of a sharp inside corner. Pour into the centre of each cavity and let it run outward, then nudge resin into the corners with a stir stick before a quick pass with a heat gun. After demolding, the top edge can be sharp; a few strokes with fine sandpaper or a file take it off.
At 1/4 in, one pour of casting resin fills each cavity — the same resin the calculator assumes for every coaster. Each coaster takes about 69 g (2.43 oz) by weight. With six cavities to fill from one cup, work in order and keep the cup moving — the last cavity gets resin that has been mixed the longest.
For a set of rounds, see how much resin for 4 coasters; for a honeycomb set, 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) - Heat gun or small torchMid-range price
A quick pass over the fresh pour pops surface bubbles. Keep it moving — lingering scorches the resin.
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 6 square coasters at 3/8 inch deep?
About 21.9 fluid ounces with 10% extra — 3.32 fl oz per coaster and 2 kits of 16 fl oz.
How much resin for 4 square coasters at 1/4 inch?
About 9.75 fluid ounces for four 4 inch squares with 10% extra — one 16 fl oz kit, with 6.25 fl oz left over.
Other common sizes
- How much resin for 4 coasters — 11.5 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