I am making a piece from a project that prescribes 14K yellow gold. I have 10K yellow gold and am wondering if there are any cautions in the substitution of 10K for 14K? This is my second real project using gold, the first was a piece that used both gold and silver in the design. Is there a distinct difference in the workability of 10k vs 14k? This project will require quite a bit of bending flattened wire (5mm x 1.2mm) along the width (as opposed to the way a ring shank is bent). Can I use 14K solder with 10K gold?
Thanks in advance 
Dan,
Generally, 10k gold is not as malleable as 14k. Which means it’s harder to work, and would require more annealing to achieve the same results. 10k is composed of 41.7% gold and 58.3% alloy, which is approximately the reverse of 14k. It also would not be a good idea to use 14k solder with 10k gold. The 10k has a lower melting temp. and would be a different color.
Tjones
Goldsmith
Thank you Tjones. I appreciate your guidance on this. I’m considering melting the 10K with an equal weight of 18K. I hope I’m correct in my assumption that I will end up with 14K?
Dan
Dan,
I’m not sure of the formula for raising the karat of gold. There is a formula, but it’s been a very long time since I used it. I think it is in one of the major jewelry making books, but I ‘m not sure where I put it, I think most of my books are up in my attic. You could probably search the net to get the correct formula.
I bigger concern for me is what shape your gold is. Is it fresh casting grain, sheet stock, or are you using finished jewelry. Old gold was the term that was used for any material that was used and turned into jewelry, vs. that which is coming directly from a refiner. If you are using just old gold, then you run the risk of porosity and brittleness, not a good thing to use to fabricate new jewelry.
Tjones
Thank you. it is old gold, a couple of rings marked 10k. I had good luck melting and using old rings for my first gold project, but they were 14k and I may have been lucky.