Metallurgist's Tools, Variant (5e Equipment)
From D&D Wiki
This kit contains all the tools such as metal shavers, a tiny-size smelter, and tiny-size crucibles, needed to obtain metal shavings and create alloys. It does not include any metal besides what makes up some of the shavers and such. For every 4 ounces of metal put into an alloy, you get 3 ounces of that alloy, and 1 ounce of slag, which can not be used as part of this process again.
Cost: 100 gp
Weight: 10 lbs.