Casting Weight Calculator
Estimate finished casting volume, pattern shrink allowance, machining stock volume, net metal weight, and total pour metal with sprue, runner, riser, and melt loss factors.
Pick a common foundry scenario. Each preset loads a material, shape, gating plan, shrink setting, machining stock, and quantity.
⚖ Casting Weight Results
Calculation Breakdown
| Material preset | Density lb/in³ | Density g/cm³ | Typical shrink | Default stock |
|---|---|---|---|---|
| Gray iron class 30 | 0.260 | 7.20 | 0.95% | 0.060 in |
| Ductile iron 65-45-12 | 0.256 | 7.09 | 1.00% | 0.070 in |
| Carbon steel casting | 0.283 | 7.83 | 2.00% | 0.100 in |
| Stainless steel CF8M | 0.289 | 8.00 | 2.10% | 0.100 in |
| A356 aluminum | 0.097 | 2.68 | 1.30% | 0.060 in |
| Tin bronze bearing alloy | 0.318 | 8.80 | 1.50% | 0.080 in |
| Yellow brass | 0.307 | 8.50 | 1.55% | 0.070 in |
| Zamak 3 zinc alloy | 0.241 | 6.68 | 0.70% | 0.025 in |
| AZ91 magnesium | 0.066 | 1.82 | 1.20% | 0.050 in |
| Ti-6Al-4V titanium | 0.160 | 4.43 | 1.60% | 0.080 in |
| Process | Sprue factor | Runner factor | Riser factor | Best use |
|---|---|---|---|---|
| Green sand with riser | 8% | 10% | 22% | General jobbing castings |
| No-bake heavy section | 10% | 12% | 35% | Thick iron or steel work |
| Shell mold | 6% | 8% | 18% | Medium detail parts |
| Investment casting | 5% | 7% | 12% | Small precise parts |
| Permanent mold | 5% | 6% | 10% | Aluminum and brass repeat work |
| Pressure die casting | 4% | 8% | 0% | Zinc, aluminum, magnesium |
| Centrifugal casting | 3% | 3% | 4% | Rings, sleeves, and bushings |
| Feature | Light casting | Medium casting | Heavy casting | Calculator note |
|---|---|---|---|---|
| Aluminum machined face | 0.030 in | 0.060 in | 0.100 in | Use lower stock for good molds |
| Iron machined face | 0.060 in | 0.090 in | 0.125 in | Allow for draft and shakeout |
| Steel machined face | 0.080 in | 0.125 in | 0.188 in | Use more on flame-cut gates |
| Cylindrical boss | 0.040 in | 0.075 in | 0.125 in | Stock adds to diameter envelope |
| Bushing bore | 0.030 in | 0.060 in | 0.100 in | Stock reduces as-cast bore size |
When you are preparing to cast a metal part, it is important to understand the difference between the weight of the finished part (also referred to as the net weight) and the total weight of the liquid metal that must be poured into a mold (the total pour weight). The net weight of the part will be the weight of that part after it are machined and polished to its final specifications. However, the total pour weight is the amount of metal that will be poured into the mold to create a part that has the correct net weights.
If you do not calculate the total pour weight correctly, you may experience a short pour of the metal into the mold, which will result in a part of scrap metal. Additionally, if you calculate the amount of metal that must be poured into the mold to create the finished part incorrectly by adding too much metal to the calculation, you will waste both energy and metal in the creation of the part, which will also reduce your profit margin for that metal part. Beyond considering the weight of the finished part alone, the weight of the part that the casting process will create include the weight of the sprue, the runners, and the risers.
Net Weight and Total Pour Weight in Metal Casting
Beyond the part that will eventually solidify into the finished metal part, these components of the mold will be necessary in the creation of a quality metal part. However, these component will not be included in the weight of the part that is created by the metal cooling and solidifying. Thus, the weight of the sprue, the runners, and the risers must be included in the calculations of the total pour weight for the metal that must be poured into the mold.
In addition to the weight of the finished part and the components of the mold, another consideration in calculating the total pour weight is the weight of the machining stock. Metal parts is almost never created in its finished state after casting; the sand molds and the metal are never perfect in there castings. Thus, some metal parts will be left as machining stock to be removed by milling or turning processes after the metal has solidified; the amount of machining stock that is required to be included in the calculations of the total pour weight will depend upon the size of the part that the mold will create and the type of metal that is being used to create that part.
For instance, more machining stock will be required for large steel parts than for small aluminum parts. If the machining stock is not accounted for in the calculations of the total pour weight, the total pour weight will be too low. Another factor to consider in calculating the total pour weight of the metal parts is the shrinkage of the metal as it solidifies.
Metals contain liquids and shrink as they solidify into metal parts. Thus, patterns will need to be created for the molds that are slightly larger than the size of the finished part; the volume of the part will need to be scaled to account for the shrinkage of the metal. Additionally, because the shrinkage of the metal is not the same for each metal, different shrinkage rates will be applied for different metal alloys.
For instance, steel will have a different shrinkage rate than aluminum. Additionally, the shrinkage rate will be cubed to calculate the volume of metal parts; if not cubed, the parts may end up being too small once they have solidified. The molding processes that the user will use to create the metal parts will impact the requirements for the gating system of the molds.
For instance, investment casting processes will be efficient for small metal parts; but large no-bake sand molds may require large risers to allow for even metal solidifications. Thus, different molding processes will have different requirements for the amount of extra metal that will be poured into the molds; low yields of metal parts are common in heavy industrial metal foundries. Low yields for metal parts mean that a great deal of metal will be poured into the molds during the creation of the parts; however, high yields are required for the solidification of metal parts to maintain their structural integrity.
Another factor to account for in the creation of metal parts is the potential for melt loss during the heating of the metal for melting. During heating, the metal will react with the sand and other materials to create dross and slag; these materials are removed from the melted metal. Thus, the amount of metal that is heated will be less than that which will be used to fill the molds; melt loss will be accounted for in the calculations of the total pour weight.
The extra metal that will be poured into the molds will ensure that the metal part will not be insufficient of metal during the pouring of metal into the molds; having more extra metal than is required is better than the potential for insufficient metal. In short, while the net weight will determine if the metal part that is created is of the correct weight for the use of that part, the total pour weight will determine how much metal should be poured into the molds. The weight of the finished metal part, the machining stock, the sprue, runners and risers, and the shrinkage allowance will all need to be calculated.
Additionally, the amount of metal that will melt during the melting process will need to be accounted for. Thus, if the difference between the net weight and the total pour weight is understood, the metal furnace can be effectively managed to minimize the amount of metal waste created during the metal casting process.
