How to Calculate Ingot Mold Capacity Before Pouring
Quick answer
Estimate ingot mold capacity by converting usable cavity volume into metal mass, then subtracting freeboard and process losses. The simple formula is: usable mass equals usable cavity volume multiplied by metal density. Do not use the same mold-weight expectation for aluminum, copper, silver, and gold.
Calculation steps
| Step | Record |
|---|---|
| Measure cavity dimensions | Length, width, depth, taper |
| Estimate usable volume | Leave approved freeboard |
| Select metal density | Use the actual alloy where possible |
| Account for loss | Dross, heel, spill margin |
| Match crucible charge | Do not overfill the mold or crucible |
What real users ask
Buyers often ask why a mold advertised for one metal does not make the same weight in another metal. Density is the main reason, with fill level and shrinkage adding variation.
Safety and setup
The mold must be dry, stable, compatible with the alloy, and placed in a controlled pour path. A math estimate does not make an unsafe mold safe.
Frequently asked questions
Can I fill a mold to the rim?
Do not assume so. Use supplier freeboard and pour-control guidance.
Why is my aluminum bar lighter than expected?
Aluminum has much lower density than copper, silver, or gold.
Should mold capacity match crucible capacity?
Match usable volumes and handling limits, not marketing kilograms.
Bottom line
Mold capacity is a volume-and-density problem. Calculate before charging the furnace so the pour has a prepared destination and a safe margin.
