Enrichment · Arts and Creativity · Maker projects

Mix enough resin
for every mould,
and not a cup more.

List your moulds and the resin's mix ratio. The calculator adds up what they hold, allows for what stays in the cup, and tells you exactly how much part A and part B to measure.

Plan a pourWhat you get

The resin calculator

The worked example is a made-up set of four coasters, six keychain bars and a leaf dish with a 1 : 1 epoxy. Nothing you type leaves this browser.

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What you get

Enrichment · Arts & CreativityFree

What you finish with
The volume of each mould, the resin to mix, and the amounts of part A and part B in millilitres or grams. It prints as a summary and downloads as a spreadsheet.
Who it is for
Students in art and maker classes, craft clubs, and families making resin pieces.
Format
Browser calculator for a phone, tablet or computer, by touch or keyboard. Up to 30 moulds. Prints a summary; downloads a spreadsheet (.csv); export and import a file.
Access
Free. No account, no sign-in and nothing to install. Everything you type stays in this browser; nothing is sent to Caveat.
Where it lives
The Arts & Creativity space in Caveat Enrichment.
Support
Questions, a correction or a request: team@caveatacademic.com.

How to use it

  1. Type the mix ratio from the label and whether it is by volume or weight.
  2. Add each mould with its shape and size, or the water it holds.
  3. Set the extra for the cup.
  4. Read the amounts of part A and part B.
  5. Print the summary and keep it by the scale.

Plan a pour

How the resin is worked out

Volume in centimetres, then the ratio.

The worked example: a coaster set4 coasters188.5 mL4 × π × 5² × 0.6All moulds268.5 mL+ 45 keychains + 35 dish+ 10%295 mLleft in the cup1 : 1147.7 + 147.7mL of A and BThe worked example: a coaster set4 coasters188.5 mL4 × π × 5² × 0.6All moulds268.5 mL+ 45 keychains + 35 dish+ 10%295 mLleft in the cup1 : 1147.7 + 147.7mL of A and B
A cubic centimetre holds a millilitre, so a mould measured in centimetres gives its volume in millilitres directly.

The arithmetic

A round mould holds π × (diameter ÷ 2)² × depth and a rectangular one length × width × depth; in centimetres the answer is millilitres. Odd shapes are easiest measured with water: fill, pour into a measuring cup and read it, then dry the mould completely. The total is raised by the extra, then split in the ratio. For a ratio by weight, millilitres are turned into grams with the mixed density.

Safety and curing

Epoxy and other casting resins give off fumes and can irritate or sensitise skin. Work in a ventilated space with nitrile gloves and eye protection, keep resin away from food areas, and follow the label for mixing time, pour depth and cure. Mixing more than the product allows at once can overheat.

Sources

  1. Occupational Safety and Health Administration. Epoxy resin hazards and safe handling (osha.gov).
  2. U.S. Environmental Protection Agency. Volatile organic compounds' impact on indoor air quality (epa.gov).
  3. National Institute of Standards and Technology. SI units: 1 cm³ = 1 mL (nist.gov/pml/owm/metric-si).
  4. OpenStax. Prealgebra 2e, section 9.6: volume of rectangular solids and cylinders (openstax.org).

The worked example is made up. Follow your resin's label and data sheet. Your figures stay in this browser. Support: team@caveatacademic.com.