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Anticipate metal loss during smelting and adjust your buying price to maintain profitability.
💡 Typical losses: Gold 0.5–1.5% · Silver 1–3% · Platinum 0.8–2%
Melt loss (merma), is the fraction of metal lost during the smelting process. It is caused by surface oxidation, volatility of certain copper alloys at high temperatures, and metal splatter. In standard workshops, the loss ranges from 0.3% to 2% depending on the type of gold and equipment used.
To factor melt loss into your buying price: Corrected purchase price = Theoretical value × (1 − Loss rate). If the theoretical value is CHF 1,000 and the loss rate is 1%, you should pay a maximum of CHF 990 to avoid a loss after smelting.
Modern induction furnaces with controlled argon atmospheres reduce loss to less than 0.1% for fine gold. Traditional flame furnaces can reach 3% or more for alloys containing zinc or tin.
Typical melt loss for gold is 0.3–2% depending on alloy and equipment. Fine gold (999‰) in an induction furnace under argon loses less than 0.1%. Alloys containing zinc can lose up to 3%.
To reduce melt loss: use an induction furnace with argon atmosphere, clean non-porous crucibles, add borax as a protective flux, and systematically recover slag (it contains 20–50% precious metal).
Prices shown are indicative (LBMA mid-market). They do not constitute investment advice.