A resin data sheet tells you how a particular resin is meant to be measured, mixed, and used. The density, mixing ratio, and maximum pour depth help you calculate material quantities and avoid mistakes that can affect the finished piece.
If you are estimating material for a project, an epoxy resin calculator can help you work out the required volume. Read the product's data sheet first, because a calculator cannot determine the correct specifications for an unidentified resin.
What does a resin data sheet tell you?
A technical data sheet, often called a TDS, describes a product's properties and recommended working conditions. For a two-part epoxy system, it may list the mixing ratio, density, working time, curing time, and permitted casting depth.
The sheet may also distinguish between resin and hardener specifications. These are separate components, so do not assume that a value listed for one applies to the other or to the combined mixture.
Three details are especially useful when planning a project. Density helps convert volume into mass, the mixing ratio tells you how much of each component to combine, and the pour-depth limit describes how deeply the product can be poured under its stated conditions.
How do you read density on a resin data sheet?
Density describes how much mass fits into a given volume. It is commonly written in grams per milliliter (g/mL) or kilograms per liter (kg/L).
For example, a density of 1.1 g/mL means that 1 mL of the stated material has a mass of 1.1 g under the stated measurement conditions. The equivalent density is 1.1 kg/L.
Density is useful when a project plan gives a volume but you need an estimated mass. Multiply the volume by the matching density, using compatible units.
| Step | Example calculation |
|---|---|
| Required volume | 500 mL (16.9 US fl oz) |
| Example density | 1.1 g/mL |
| Mass calculation | 500 mL × 1.1 g/mL = 550 g |
| Approximate US mass | 550 g = 19.4 oz |
Check the arithmetic another way: 1.1 g/mL is 1,100 g/L, and 0.5 L × 1,100 g/L equals 550 g. Both calculations give the same result.
This example assumes that the stated density applies to the material being measured. If the sheet lists separate densities for resin and hardener, use the relevant value for each component rather than treating them as identical.
What does the mixing ratio mean?
The mixing ratio states how much resin and hardener must be combined. It may be given by volume or by weight, and those methods are not automatically interchangeable.
For example, a product with a 2:1 ratio by volume requires two volume parts of resin for every one volume part of hardener. If the instructions instead specify a weight ratio, the amounts must be measured by mass.
For a worked example, suppose the data sheet specifies a 2:1 volume ratio and you want 300 mL (10.1 US fl oz) of mixed material. Add the ratio parts, divide the target volume by that total, and multiply by each component's share.
| Step | Example calculation |
|---|---|
| Total ratio parts | 2 + 1 = 3 |
| Volume per part | 300 mL ÷ 3 = 100 mL |
| Resin amount | 2 × 100 mL = 200 mL |
| Hardener amount | 1 × 100 mL = 100 mL |
| Total check | 200 mL + 100 mL = 300 mL |
Check the ratio by dividing 200 mL by 100 mL. The result is 2, confirming the required 2:1 proportion. These are example quantities, not a recommendation for an unspecified product.
One detail matters when working from a weight ratio: the total mass of the mixture is not the same as its volume. Do not use a volume calculator to convert between them unless the required density information and measurement method are known.
What does maximum pour depth mean?
Pour depth is the height of resin in the mold, measured vertically from the bottom of the resin layer to its surface. It is different from the total volume needed to fill a mold.
The maximum pour depth is a product-specific limit under stated conditions. A deeper layer may retain more heat during curing, and the allowed depth can change with the formulation, mold, batch size, and working conditions.
Do not assume that every epoxy can be poured to the same depth. A coating resin and a casting resin may have different intended uses, even if both are sold as epoxy.
For a rectangular mold, you can estimate the required volume from its internal dimensions. Multiply the inside length by the inside width and by the intended resin depth. Keep all three measurements in the same units.
| Measurement | Example value |
|---|---|
| Inside length | 30 cm (11.81 in) |
| Inside width | 20 cm (7.87 in) |
| Intended depth | 2 cm (0.79 in) |
| Volume calculation | 30 × 20 × 2 = 1,200 cm³ |
| Equivalent volume | 1,200 mL (40.6 US fl oz) |
The reverse check is 1,200 cm³ ÷ (30 cm × 20 cm) = 2 cm of depth. The arithmetic is consistent, but the calculated volume does not prove that the product can be poured at that depth.
Check the manufacturer's stated maximum depth before using the result. If the product requires several layers, calculate each layer separately and follow its recoat instructions.
How to use an epoxy resin calculator with a data sheet
A calculator can help with the arithmetic once you have identified the product's specifications. Use the data sheet to supply the correct values rather than guessing the ratio or permitted depth.
- Find the mixing ratio on the data sheet and note whether it is by volume or weight.
- Measure the mold's internal length, width, and intended fill depth, using consistent units.
- Enter the dimensions or target volume into the calculator, matching its measurement units.
- Enter the correct mixing ratio if the calculator provides ratio inputs.
- Review the calculated amount and compare the planned pour depth with the product's stated limit.
- Check whether the calculator estimates volume, mass, or both before using its result to measure material.
If the calculator does not support the ratio method listed on the data sheet, calculate the mixture by hand. A correct calculation still depends on accurate measurements and the right product specifications.
Which mistakes cause the biggest calculation errors?
- Confusing volume with mass: A 500 mL volume is not automatically 500 g. At the illustrative density of 1.1 g/mL, it corresponds to 550 g, a difference of 50 g.
- Using the wrong ratio method: A volume ratio cannot be treated as a weight ratio without suitable product data. The resulting component amounts may be wrong even when the ratio arithmetic looks correct.
- Measuring external mold dimensions: A mold's outer dimensions may overstate its internal capacity. The error depends on wall thickness and shape, so measure the cavity that will hold the resin.
- Ignoring the depth limit: A mold may have enough capacity for a deep pour, but the resin may not be designed for that depth. Extra material can be wasted if the project must be divided into layers.
- Rounding too early: Rounding each component before finishing the calculation can introduce avoidable measurement errors. Keep the working figures until the final amount, then round to match the measuring equipment.
When handling or disposing of resin components, follow the manufacturer's instructions and safety data sheet for the specific product.
When are these calculations less reliable?
Density calculations depend on the stated material and measurement conditions. Temperature can affect density, and a value for one component may not describe the combined mixture exactly.
Mold-volume calculations also assume a regular shape with known internal dimensions. Curved molds, sloped walls, embedded objects, and uneven surfaces can change the amount required.
Finally, a calculated volume cannot predict every curing result. The arithmetic does not establish the correct pour depth, working time, curing time, or suitability of a product for a particular project.
When the data sheet gives a range or a condition for a stated value, use that information rather than treating the number as universal. The product's own instructions determine which density, ratio, and depth limits apply.