ArtCalcs.uk
Bronze Weight Calculator — Wax to Bronze Conversion
Estimate the weight and cost of a bronze casting from wax model dimensions.
How We Calculate This
How Bronze Weight Calculation Works
Bronze weight = (Wax weight ÷ Wax density) × Bronze density
In lost-wax casting the bronze occupies exactly the space the wax pattern held, so weighing the wax gives the true casting weight directly — no guessing at solid volume. The wax weight is divided by wax density (~0.9 g/cm³) to get the cast volume, then multiplied by bronze density (~8.8 g/cm³). Because the wax pattern is itself a hollow 5-8 mm shell (which becomes the 5-8 mm bronze wall), this volume-replacement method correctly captures hollow art bronze rather than overweighting it as a solid block. Bronze is roughly 9.8× heavier than the same volume of wax.
Default density is 8.8 g/cm³ (phosphor bronze). Silicon bronze (Everdur), the most common UK sculpture alloy, is a touch lighter at ~8.5-8.75 g/cm³ — adjust it under Advanced Options for a tighter figure.
Frequently Asked Questions
Use a digital kitchen scale. Weigh the complete wax model including sprues if already attached. For hollow wax shells, the weight is typically 60-80% less than a solid equivalent.
Bronze density is 8.8 g/cm³ compared to wax at 0.9 g/cm³ — nearly 10 times heavier. A 500 g wax model becomes approximately 4.9 kg in bronze. This significant weight difference affects handling, shipping and display.
Bronze ingot for art casting (silicon bronze / Everdur is the usual sculpture alloy; phosphor bronze is also used) costs roughly £12-20 per kg at retail in small quantities — a UK foundry supplier listed an 8.5 kg silicon-bronze ingot at £158.95 in mid-2026 (~£18.71/kg). Buying in bulk is cheaper. Either way the raw metal is a small fraction of the total casting cost, which is dominated by labour, shell building and finishing.
Professional bronze casting in the UK typically costs £30-60 per kg of finished bronze, all-inclusive. A 5 kg casting might cost £150-300. This includes shell building, burnout, pouring, fettling and basic patina.
Home bronze casting requires specialist equipment: a furnace reaching 1100°C, crucibles, investment materials and safety gear. Most artists use professional foundries. However, aluminium casting at lower temperatures is feasible for home workshops.
Related Calculators
Casting Calculator
Calculate resin, plaster, concrete or jesmonite volume and weight for sculpture casting. Includes waste allowance and cost estimate.
Armature Wire Calculator
Calculate wire armature requirements for sculptures including total wire length, weight, base plate size, support rod height and material cost estimate.
Clay Weight Calculator
Estimate clay weight for solid or hollow sculptures. Covers earthenware, stoneware, porcelain and air-dry clay with shrinkage.
Mould Volume Calculator
Calculate the volume of silicone, plaster, alginate or jesmonite needed to make a sculpture mould. Includes weight and cost estimates.
Plaster Mix Calculator
Work out the correct plaster-to-water ratio by weight for casting and mould making. Covers Plaster of Paris, Herculite and more.
Was this calculator helpful?
Last updated: February 2026
All calculations are estimates. Always verify quantities before purchasing materials.