Metal densities and underwater weight for lure parts
Density of the metals used for sinkers, lure weights, eyes and rings, and how much of the weight is left once the part is under water. Use it to choose a material or to work out whether a lure floats or sinks.
| Material | Density (g/cm³) | Volume of 10 g (cm³) | Size vs lead, same weight | Weight in fresh water | Weight in sea water |
|---|---|---|---|---|---|
| Stainless steel SUS304 | 7.93 | 1.26 | 143% | 87.4% | 87.1% |
| Stainless steel SUS316 | 7.98 | 1.25 | 142% | 87.5% | 87.2% |
| Lead | 11.34 | 0.88 | 100% | 91.2% | 91.0% |
| Tungsten (pure) | 19.25 | 0.52 | 59% | 94.8% | 94.7% |
| Tungsten alloy | 18.00 | 0.56 | 63% | 94.4% | 94.3% |
| Bismuth | 9.78 | 1.02 | 116% | 89.8% | 89.5% |
| Brass C3604 | 8.50 | 1.18 | 133% | 88.2% | 87.9% |
| Copper | 8.96 | 1.12 | 127% | 88.8% | 88.6% |
| Steel | 7.85 | 1.27 | 144% | 87.3% | 86.9% |
| Zinc | 7.13 | 1.40 | 159% | 86.0% | 85.6% |
| Tin | 7.29 | 1.37 | 156% | 86.3% | 85.9% |
| Titanium | 4.51 | 2.22 | 251% | 77.8% | 77.3% |
| Aluminium A5052 | 2.68 | 3.73 | 423% | 62.7% | 61.8% |
"Size vs lead" is the volume of a part of the same weight (lead = 100%). Underwater weight is the share of the dry weight that remains in water. Alloy densities are typical values; check your supplier's specification for exact figures.
How underwater weight is calculated
A submerged part is pushed up by the weight of the water it displaces, so its weight in water is:
Weight in water = mass − volume × water density = mass × (1 − water density ÷ metal density)
Water density: fresh 1.000 g/cm³, sea about 1.025 g/cm³
For a 10 g part:
- Lead: 9.12 g in fresh water, 9.10 g in sea water
- Tungsten alloy: 9.44 g fresh, 9.43 g sea
- Stainless steel SUS304: 8.74 g fresh, 8.71 g sea
- Titanium: 7.78 g fresh, 7.73 g sea
- Aluminium: 6.27 g fresh, 6.18 g sea
The denser the metal, the less weight it loses in water. Light metals such as titanium and aluminium lose much of their weight, so they make poor sinkers.
Materials at a glance
- Lead: cheap and easy to cast, the standard sinker material. Some waters and regions restrict or discourage it for environmental reasons.
- Tungsten: about 1.6 times as dense as lead, so the same weight is much smaller. Hard to machine and expensive.
- Bismuth and tin: lead substitutes. They are less dense, so the same weight is larger (about 1.2× for bismuth, 1.6× for tin).
- Brass and copper: beads, sinkers and blades. Easy to machine, with a distinctive color.
- Stainless steel: corrosion resistant; the usual choice for split rings, eight rings and wire. SUS316 (AISI 316) resists salt water better.
- Titanium and aluminium: light and strong, for parts that should not add weight.
Whether a lure floats or sinks
A lure floats when the total weight of body, weights, eyes, rings and hooks is less than its volume × the water density, and sinks when it is more. Knowing the volume and mass of each metal part makes this calculation exact.
Make it in Lure Parts Modeler →Enter the dimensions and get the volume, mass, weight in fresh and sea water and center of mass of a metal part, plus a 3D model to download.