How much epoxy for a 20 oz skinny tumbler?
You need about 32 milliliters (1.07 fluid ounces) of mixed epoxy per coat for a 20 oz skinny tumbler, including what stays in the mixing cup — 16 ml each of Part A and Part B for a 1:1 epoxy. Two coats is about 64 ml, so a 16 fl oz kit does 7 tumblers coated one at a time, or 8 coated together.
How to work it out
- π × 2.9 in × 8.25 in = 75.2 sq in per tumbler
- × 0.02 in = 24.6 ml on the tumbler; × (1 + 5%) + 5.91 ml left in the cup = 1.07 fl oz per coat (one batch) × 2 = 2.15 fl oz
- (473 ml kit ÷ 2 coats − 5.91 ml cup loss) ÷ 25.9 ml per tumbler per coat = 8 tumblers mixed together
- Per coat: 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 0.54 fl oz (0.64 oz) + Part B 0.54 fl oz (0.53 oz)
The 20 oz skinny is the most common tumbler blank: straight-sided, about 2.9 in across, with around 8¼ in of coated height once you leave a bare band at the rim. Because the sides don’t taper, one diameter measurement is enough.
Adjust for your project
More options: waste · cup loss · ratio …
- Per coat when mixing — Part A (resin)
- 0.54 fl oz (15.9 ml)
- Per coat when mixing — Part B (hardener)
- 0.54 fl oz (15.9 ml)
- All coats
- 2.15 fl oz (63.6 ml)
- Tumblers per kit (all coats, mixed together)
- 8 tumblers
- Coated area (per tumbler)
- 75.2 sq in
- How it batches: you mix one batch per coat for the tumbler in the batch, and about 0.2 fl oz stays in the cup each time — so coating several at once wastes less per tumbler. Tumblers per kit assumes every tumbler the kit covers is coated from one batch per coat (8); coating them one at a time, the kit does 7.
- KS Resin’s rule of thumb is 1–1.5 ml of epoxy per ounce of tumbler capacity — 20–30 ml for a 20 oz. Real use depends on viscosity, room temperature and how long you spread, so weigh what’s left in your cup after the first tumbler and adjust the thickness to match.
Epoxy for a 20 oz skinny tumbler, by coat thickness
| Coat | Tumbler epoxy to mix per coat | All coats | Tumblers per kit (all coats, mixed together) |
|---|---|---|---|
| Thin (≈1/80 in) | 0.75 fl oz | 1.49 fl oz | 14 tumblers |
| Typical (≈1/50 in) | 1.07 fl oz | 2.15 fl oz | 8 tumblers |
| Heavy (1/32 in) | 1.57 fl oz | 3.13 fl oz | 5 tumblers |
What to know about coating a 20 oz skinny tumbler
The 32 ml figure sits just above KS Resin’s rule of thumb (1–1.5 ml per ounce of capacity, so 20–30 ml for this cup). That is deliberate: only about 25 ml actually ends up on the steel, and the rest is about 6 ml left in the mixing cup plus a 5% allowance for the stick and gloves. If your cup scrapes cleaner than that, lower the cup loss under More options; pick the thin coat and the figure drops to about 22 ml.
Mix for two or three cups at once if you can. Thirty-two milliliters is a small batch — about a tablespoon of each part — and small batches are the easiest to get off-ratio, which shows up later as soft or tacky patches. Medicine cups marked in milliliters, or a scale that reads to 0.1 g, make 16 ml of each part easy to hit. Coating three skinnies from one mix takes about 84 ml (2.82 fl oz) per coat — 28 ml a tumbler instead of 32, because they share one cup’s worth of loss.
Leave the top half inch or so bare. Most makers tape a clean band at the rim so the lid seals on steel and lips touch the cup, not the coating, and a matching band at the base keeps drips off the turner. Measure the coated height between the tapes, not the full height of the blank.
The first coat usually locks down glitter or vinyl and comes out uneven; the second is the smooth, glossy one. If you are working through a bulk order, compare this with how much epoxy for a 30 oz tumbler — the bigger cup uses barely more epoxy.
Different size? Use the full Tumbler Epoxy Calculator.
What you’ll need
- Tumbler epoxy (1:1 thin-coat)Mid-range price
Made to be spread thin on a cup turner, with a working time long enough to even out the coat.
See options on Amazon (opens in a new tab) - Cup turner for tumblersMid-range price
Slowly rotates a coated tumbler so the epoxy cures evenly instead of sagging to one side.
See options on Amazon (opens in a new tab) - Graduated mixing cups & stir sticksBudget price
Small cups marked in ounces and ml for art, coasters and tumblers. Use a fresh cup when you transfer to a second container.
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 epoxy for three coats on a 20 oz skinny tumbler?
About 95 milliliters in total (3.22 fl oz) — 32 ml a coat — so a 16 fl oz kit covers 4 tumblers coated one at a time, or 5 coated together.
How much epoxy to coat three 20 oz skinny tumblers in one batch?
About 84 milliliters (2.82 fl oz) per coat for all three, or 167 ml for two coats.
How much epoxy for a thin coat on a 20 oz skinny tumbler?
About 22 milliliters per coat at a thin coat of about 1/80 in, cup loss and allowance included — enough for 10 tumblers per 16 fl oz kit at two coats one at a time, or 14 tumblers coated together.
Other common sizes
- How much epoxy for a 30 oz tumbler — 1.1 fl oz
Sources
- KS Resin — How much epoxy resin do I need for a tumbler? (opens in a new tab) — Manufacturer rule of thumb: 1–1.5 ml of epoxy per ounce of tumbler capacity (20–30 ml for a 20 oz, 30–45 ml for a 30 oz)
- ArtResin — FAQ (opens in a new tab) — Work at about 75–85°F (24–30°C); cured resin tolerates heat only up to about 120°F
- Epoxyworks — The Basics of WEST SYSTEM Epoxy Resin and Hardener (opens in a new tab) — Temperature drives working time and cure; pot life vs working time