How the calculation works
Subtract the master volume from the internal box volume up to your pour level. The space left over is what the silicone fills.
Silicone volume = box volume − master volume. Then convert it to mass: mass in kg = volume in mL / 1000 × density in kg/L. With the example values, 450 − 120 = 330 mL, or 0.363 kg at 1.1 kg/L.
The cost uses the total volume including your selected allowance. Include channels in the box volume and adjust the allowance for losses in the cup and on your tools. Enter your price in USD per kilogram. The sample price is illustrative; no currency conversion is performed.
Volume to mass
| Volume | Mass at 1.1 kg/L |
|---|---|
| 100 mL | 0.11 kg |
| 250 mL | 0.28 kg |
| 500 mL | 0.55 kg |
| 1000 mL | 1.1 kg |
Where do I get the STL volume?
Use the enclosed volume of a closed master mesh from CAD or a slicer. Do not use filament consumption: infill changes that number without changing the volume displaced by a sealed master. In CraftMold, check the STL and select its bottom plane before generating the formwork.
A few common questions
Why is this only an estimate?
The calculation uses geometry. Measurements can be off, and some silicone stays in the cup and on your tools. It gives you a starting point, not a guaranteed batch size.
How much extra should I mix?
With 330 mL of net silicone, a 10% allowance adds 33 mL. At 1.1 kg/L, the total is 399.3 g. Choose 0%, 5%, 10%, or enter your own percentage. The right allowance depends on your process.
Does this give me the amount of each component?
No. The result is the total mixed mass. Split it into A and B using the ratio on your product data sheet. A ratio by weight is not interchangeable with a ratio by volume.