Melting scrap gold

[Jimbo]

Hi, I am looking for some guidance regarding melting scrap gold for re-use in a ring that I am constructing.

I have about 22g of 9ct yellow gold that I have melted down and will be rolling the ingots down into the various thickness's required for the ring construction. Will there be any issue in terms of assay quality of the final piece if I melt and re-melt the gold to get the various components. Should I be adding casting grain to the melt at any point to pull the gold back to 9ct assay quality.

The gold that I started with was all provided by my client and hallmarked as 9ct. Part of the design introduces a new component of white gold, the finished product therefore will have to be hall marked - hence my concern regarding maintainng assay quality of the yellow gold.

Kind Regards Jim

[Dennis]

To be sure of passing the assay it is customary to add a proportion of fine metal to the melt. I don't use recycled metal, so I'm not sure how much, but in the case of 9ct, about 5% is my guess. Someone will be along shortly with a more authoritative reply. Dennis.

[enigma]

I do melt my scrap gold and silver down quite a lot without adding casting grain in and have not had any problem with having it assayed.
As long as no other metal gets mixed in I don't see why there should be a problem?

[Unhindered]

if I know im having it hallmarked I add a tiny bit of 18ct to a 9ct melt just incase, but it may not be needed its just habit from a previous job! They weren't exactly the best goldsmiths though so it could be wrong!

[Jimbo]

Thank you all for your responses. Sounds like I should add a small amount of casting grain to be on the safe side. Some of the scrap only had '375' marks and not full hall marks, so will err on the side of caution..

Thanks again.

[TeeDee]

I do melt my scrap gold and silver down quite a lot without adding casting grain in and have not had any problem with having it assayed.
As long as no other metal gets mixed in I don't see why there should be a problem?

Sarah,
Do you ever have a problem with hard solder? I did a melt of 9ct mixed scrap and when I went to solder with hard, I managed to get the parent metal to slump. It seemed that the resultant alloy was very close to the melting range of the hard solder. (See pic) Had to re melt and use medium solder.

Also the alloy was streaky as though the copper had seperated. Looked quite nice though but I wonder how it would stand assay
Tim

[Dennis]

Yes, not Sarah, but I had that experience many years back and now always start with 9ct medium. Dennis.

[Nick martin]

As Dennis has said, add a bit of a higher purity gold to ensure it meets the 9ct hallmark standard.

Also before beginning to melt the scrap gold down, if I were you I'd try my best to get rid of any obvious bits of solder before hand as this lowers the purity.

Nick

[Tabby66]

I always add a 'bit' of higher purity gold, to take account of solder, etc,.....I also warn the client that it will be assayed and carat cannot be guaranteed (explaining that a fraction below will give a lower or no assay mark).....I generally speak with the assay office so know (verbally) exactly what it has been assayed at. You can get an assay report at extra cost, but I don't generally offer this to customers.

[enigma]

Hi Tim

So far Ive only had that with white, not yellow or red, I always use hard solder but then again I haven't masses of experience so could just have been lucky.