PTFE Ball Weight Chart
Weights for solid virgin PTFE balls, calculated from sphere volume and a density of 2.16 g/cm³. Use these for freight estimates, check-valve spring sizing and float calculations.
Solid virgin PTFE — weight by diameter
| Diameter | Inch | Volume (cm³) | Weight (g) |
|---|---|---|---|
| 3 mm | 0.014 | 0.031 | |
| 4 mm | 0.034 | 0.072 | |
| 5 mm | 0.065 | 0.141 | |
| 6 mm | 0.113 | 0.244 | |
| 8 mm | 0.268 | 0.579 | |
| 9.525 mm | 0.375” | 0.452 | 0.977 |
| 10 mm | 0.524 | 1.13 | |
| 12 mm | 0.905 | 1.95 | |
| 12.7 mm | 0.5” | 1.073 | 2.32 |
| 15 mm | 1.767 | 3.82 | |
| 19.05 mm | 0.75” | 3.620 | 7.82 |
| 20 mm | 4.189 | 9.05 | |
| 25 mm | 8.181 | 17.67 | |
| 25.4 mm | 1” | 8.580 | 18.53 |
| 30 mm | 14.137 | 30.54 | |
| 38.1 mm | 1.5” | 28.958 | 62.55 |
| 40 mm | 33.510 | 72.38 | |
| 50 mm | 65.450 | 141.37 |
Weight scales with the cube of diameter, so doubling the diameter multiplies weight by eight. That is why a check ball two sizes up can need a completely different spring.
Adjusting for filled grades
Multiply the virgin weight above by the ratio of densities:
| Grade | Approx. density (g/cm³) | Multiplier vs virgin |
|---|---|---|
| Virgin PTFE | 2.16 | 1.00 |
| 25% glass-filled | 2.24 | 1.04 |
| 25% carbon-filled | 2.10 | 0.97 |
| 60% bronze-filled | 3.90 | 1.81 |
A bronze-filled ball weighs close to twice its virgin equivalent, which changes cracking pressure in a check valve significantly. If you are substituting grade, recheck the valve behaviour rather than assuming a like-for-like swap.
Hollow balls
A hollow ball’s weight depends on wall thickness and cannot be read from this chart. For float applications, buoyancy rather than weight is usually the governing requirement — send the fluid density and the required float force.
What to send with an enquiry
Diameter and tolerance, grade, sphericity requirement, and quantity. If the ball is for a check valve, the seat bore and the cracking pressure matter more than the ball weight itself.
Related references
Diameter tolerance and sphericity are covered on the ball size and tolerance grade chart — for a check valve, sphericity governs shutoff more than diameter does.
Grade affects both weight and behaviour: see virgin PTFE balls for the standard, and the PTFE ball for check valve page for how ball mass interacts with cracking pressure. Where the duty is steam or cryogenic, grade selection changes again — see PTFE ball for steam service.
Send your seat bore, cracking pressure and media to HEMSUN for a size and grade recommendation.