Lemel is the jewellery trade term for the small shavings of precious metals such as gold and silver (and sometimes platinum) that are left from filing and sawing, techniques which the handmade jewellery pieces require.Think of it as the wood workshop equivalent of sawdust. Except in the jewellery trade, our filings are caught in a tray or a canopy of leather under our benches, then swept up and placed in a "lemel jar". This is then sent to a refinery to be melted down and refined into separate metal elements and then precious metal alloys which are used in jewellery manufacture. Most refineries have a minimum weight of metal for processing in order for you to get the most out of the refining fee and for it to be a cost effective process for the refining company.
The same goes for what we call "scrap". This is a collection of all the pieces of clean bar and plate and chenier which are left over from production which are saved in a separate jar in case the jeweller needs to use them later. When the pieces get too small to use, they are melted down (doing it yourself, rather than sending it to the bullion company is cheaper) and then poured into cast iron moulds in the shape of bar or plate to be used again.
When I say "clean" bar and plate, I mean without any solder on its surface. The reason for this is that solder is designed to have a lower melting point than the actual metal you are soldering (you don't want to melt your job when you are trying to solder two pieces together!) and so once you've melted down your scrap and it has cooled, the solder will show up as a dark spots in your metal.
The way to avoid this is:
- only use as much solder as is required (you can always add more solder later)
- remove any excess solder by filing in the case that you've used too much
- simply cut off the portion of the scrap piece with solder on it and toss it in the lemel to be refined, keeping the clean piece in the scrap jar
Now the important thing is, that you must keep your alloys separate!!!
At the end of the day and when switching between different alloys, pick out your scrap and sweep up your lemel. Keep two jars for each of the precious alloys you use (sterling silver, 9 carat gold, 14 carat gold, platinum, etc) with clear labels. You don't want to have to test each piece of scrap metal before you melt it in order to make sure each of the alloys remain pure. If different alloys are melted together you will have to send it to the refinery in order to separate the element metals and create the correct alloys needed for jewellery.
What are your thoughts, fellow jewellers? I'd like to hear your tips on melting down scrap or your stories and experiences with refineries.
Until then,
-Kristina.
