Mold Resin Volume Calculator
Estimate resin volume, mixed weight, Part A and Part B amounts, displacement from inserts, fill percentage, shrinkage allowance, and waste for common casting molds.
Load a realistic mold setup, then adjust dimensions, density, fill level, shrinkage, waste, and ratio for your actual resin system.
| Resin profile | Typical density | Ratio example | Use note |
|---|---|---|---|
| Art epoxy | 1.08-1.14 g/mL | 1:1 | Coasters, trays, shallow molds |
| Deep pour epoxy | 1.05-1.12 g/mL | 2:1 | River pours and thick blanks |
| Clear polyurethane | 1.04-1.12 g/mL | 1:1 | Fast small castings and parts |
| Casting polyester | 1.10-1.20 g/mL | 100:2 | Hard clear casts with more shrink |
| Mold shape | Formula basis | Main fields | Best fit |
|---|---|---|---|
| Rectangle | L x W x D | Length, width, depth | Trays, slabs, blanks |
| Cylinder | pi x r2 x D | Diameter, depth | Coasters and round pucks |
| Oval | pi x L/2 x W/2 x D | Length, width, depth | Pendants and oval trays |
| Half sphere | 2/3 x pi x r3 | Diameter only | Domes and cabochons |
| Pyramid | L x W x D / 3 | Base length, width, height | Paperweights and display molds |
| Ratio type | Calculator entry | Part A share | Part B share |
|---|---|---|---|
| Equal parts | 1 and 1 | 50.0% | 50.0% |
| Deep pour epoxy | 2 and 1 | 66.7% | 33.3% |
| Urethane set | 1 and 0.9 | 52.6% | 47.4% |
| Polyester catalyst | 100 and 2 | 98.0% | 2.0% |
| Casting preset | Typical mold | Suggested waste | Spec cue |
|---|---|---|---|
| Round coaster set | Four shallow cylinders | 8% | Use headroom for doming |
| River board channel | Long rectangle | 12% | Subtract wood islands |
| Jewelry pendant | Small oval cavities | 15% | Cup loss matters most |
| Dice blank block | Rectangular block | 10% | Degas or pressure cast |
| Pyramid paperweight | Square pyramid | 12% | Fill slowly at the tip |
Calculating the amount of resin that you will need before you begin your pour are a necesary step in the resin pouring process. The amount of resin that you use will determine if your project are succesful or not. Using too little resin will lead to the situation of running out of resin before you have poured your mold filled with resin.
Using too much resin will waste the expensive resin, or the resin may have began to gel prior to the completion of your resin pour. In order to calculate the amount of resin that is needed for your mold, you must account for the volume of the mold, the volume of the objects that is to be placed within that mold, and the volume of the resin that will be lost during the process of mixing and pouring the resin. To calculate the amount of resin that will be needed, you must first measure the dimensions of the mold in order to calculate the total mold volume.
How Much Resin Do You Need
However, molds of different shapes will have different mathematical calculation that are required to determine the volume of the mold. Furthermore, you must subtract the volume of any objects that are to be placed into the mold from the total mold volume, as these objects will take up the resin volume within the mold. Beyond measuring the mold and accounting for the objects within the mold, there are additional factors that must be considered in the calculation of the amount of resin that is needed.
One factor is the density of the resin; resin is more denser than water. Furthermore, you must mix the resin according to the specified ratio of Part A and Part B to resin; different types of resin utilize different ratios of Part A and Part B. Additionally, other factors that will change the amount of resin that is needed are the shrinkage of the resin as it sets and cures, and the loss of resin during the mixing of the resin and pouring of the resin. These factors require the addition of percentages to the total volume that is calculated for the mold.
Small molds lose a more higher percentage of the resin due to waste when you use the resin for small molds. You must also account for headroom. Headroom is the space between the poured resin and the top of the mold.
If you want the poured resin to have a flat top, you will need to pour the resin to the rim of the mold. However, if you would like the resin poured into the mold to have a domed top, you will need to add additional resin to ensure that the resin reaches the desired height when the resin has set. Thus, you must account for the headroom by adjusting the calculations for the resin that will be poured into the mold.
Furthermore, another factor to consider is the batch size of the resin pour. If you calculate the total weight of the resin that will be poured into the mold is very heavy, you may not be able to pour all of the resin at once due to the resin setting prior to all of the resin being poured. Therefore, you may have to split the resin batch into multiple batch of resin.
However, each batch must utilize the same ratio of Part A and Part B to the resin to maintain the resin quality. Furthermore, utilizing multiple batches will allow you to manage the resins working time, and prevent you from racing against the resins curing time. Finally, environmental factor such as the humidity and the temperature of the room can affect the resin’s cure times.
As a result, you should use the resin volume calculator prior to the pouring of the resin to determine a reliable amount of resin to use. Furthermore, you should measure the amount of resin that is to be used twice to ensure accuracy. By calculating the amount of resin that is needed prior to beginning the pouring of the resin, you gain control over the resin pour.
By calculating the resin prior to mixing, you can plan the placement and the addition of any objects to the mold, and you can plan the resin pour in a way that prevents the guessing of the amount of resin that is needed to complete the mold pour. Thus, planning the resin pour will lead to more consistent and succesful resin projects.
