Metal loss calculator: how much metal each technique costs you
Enter how much metal goes into the process and tick the techniques it goes through. You get the net weight out, the grams lost and what they are worth at today's gold or silver price. The percentages are starting values: adjust them to what you measure at your bench.
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Metal loss calculator
Losses apply in order, each on what the previous one leaves.
47.77 g
Of 50.00 g going in, 47.77 g comes out: you lose 2.23 g (4.45 %).
- Loss
- 2.23 g
- Total loss
- 4.45 %
- Pure metal lost
- 1.298 g
- Money in the loss
- USD 172.50
How to work out the loss on a piece
- 1.Enter the weight of metal going into the process.
- 2.Choose the metal and its karat or fineness, to put a price on the loss.
- 3.Tick the techniques the metal goes through and adjust each percentage if you know yours.
- 4.Read the net weight, the loss in grams and what it is worth.
Where metal loss comes from
Every time metal is melted, filed or polished, some stays in the crucible, the investment, the dust or the water. The gap between what goes in and what comes out is the loss, and in a workshop it is money leaving every day.
Losses compound: melt and then sandblast, and the sandblasting percentage applies to what came out of the melt, not the starting weight. That is why the calculator applies them one after another.
The starting values are typical workshop figures: ingot melting around 1 %, lost-wax casting 2 to 5 %, sandblasting 0.5 %, polishing 1 % and dirty scrap —with solder, stones or grit— 5 to 15 %. Measure yours by weighing before and after for a few weeks.
Part of the loss can be recovered: filings, polishing dust and rags can be sent for refining. What cannot be recovered is the real loss.
Frequently asked questions
How much loss is normal in lost-wax casting?
Between 2 and 5 % per pour in a well-run workshop, counting what stays in the investment and crucible. The button and sprues are not loss: they are recovered and remelted.
How do I work out my workshop's real loss?
Weigh the metal you issue to each process and what comes back, pieces plus offcuts. The difference divided by what you issued is your loss percentage. Enter it in the calculator.
Why does dirty scrap lose so much?
Because part of its weight is not precious metal: lower-karat solder, bits of stones, abrasive and grit. In the melt that part leaves with the slag.
Are losses applied one after another?
Yes. Each technique loses a percentage of the metal that reaches it, so the total loss is slightly less than the plain sum of the percentages.
How much should I charge a customer for loss?
Many workshops charge loss separately, in grams of metal or in money. The calculator gives you both figures for your quote.