About

Epoxy resin is an unforgiving medium. Precision is not optional; it is a chemical requirement. This tool is designed for professional woodworkers, jewelers, and resin artists who demand exactitude in their pours. Unlike generic calculators, this system accounts for complex geometries (from river tables to hexagonal coasters) and critical density variations between resin and hardener.

Mixing by volume is standard, but mixing by weight offers superior accuracy. This calculator supports both, applying specific gravity coefficients to ensure your stoichiometry is correct. It also addresses the logistical challenges of the workshop: tracking financial costs per pour and managing the Pot Life - the critical window before the resin begins to gel and becomes unworkable. Use the integrated safety buffer to account for cup residue, ensuring you never run short mid-pour.

Formulas

The core volume determination relies on geometric integration. For a standard cylindrical coaster, we use:

V = π ⋅ r² ⋅ h

For hexagonal prism casting, the area of the base is calculated as:

V = 3√32 ⋅ s² ⋅ h

When converting to weight (Gravimetric Mixing), we apply the density (ρ) of each component:

Mass_Total = {

V_A ⋅ ρ_A for Part AV_B ⋅ ρ_B for Part B

Reference Data

Resin Brand / Type	Typical Ratio (Vol)	Typical Ratio (Weight)	Pot Life (min)	Cure Time (hr)	Density A (g/ml)	Density B (g/ml)
Standard Tabletop Epoxy	1:1	100:83	20-30	24	1.15	0.96
Deep Pour (Casting)	2:1	100:45	45-60	48-72	1.12	0.94
Fast Set / Laminating	1:1	100:85	10-15	12	1.16	0.98
Art / Coating Resin	1:1	100:83	45	24	1.14	0.95
Marine Epoxy (Standard)	3:1 or 5:1	Varies	15-25	24	1.18	0.99
Urethane Casting Resin	1:1	100:90	2-5	0.5-1	1.05	1.02
Silicone (Mold Making)	10:1 or 1:1	10:1	30-45	6-24	1.10	1.10
Polyester Resin	~100:1 (Drops)	Weight Only	15	4-6	1.20	N/A

Frequently Asked Questions

Resin (Part A) is typically much denser and heavier than Hardener (Part B). A 1:1 volume ratio might actually be a 100:83 weight ratio. If you mix 100g of A and 100g of B for a 1:1 volume resin, you will have too much hardener, which can cause overheating, yellowing, or brittleness.

Resin clings to the sides of your mixing cup and stirring stick. We recommend a 5-10% buffer to account for this "cling loss". It is far cheaper to throw away 10ml of excess resin than to ruin a project because you were 5ml short.

Use the "Irregular / Displacement" tab. Alternatively, approximate the river as a series of rectangles: measure the width at 5-10 different points along the river, take the average width, and multiply by the total length and depth.

The timer indicates the working time before the resin begins to gel (exotherm). Once it gels, it cannot be poured or self-level. You should aim to have your pour completed and torched (for bubbles) at least 5-10 minutes before the pot life expires.