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  1. #1
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    Default Bright cutting white gold

    Hi All,
    I been working on a white gold pendant that is cast out of 14k.
    This is from Au in Michigan. Their alloy is 14KP 930, which they tell me is a
    low nickel alloy. They are a induction casting firm rather than using a
    centrifuge. They use vacuum assist.

    What I normally use for white gold bright cutting is a 120 with a very small heal.
    With this particular alloy, I find myself plunging into the metal.
    For now I using the gravers that I normally use for pewter with a very long heal.

    This alloy seems to have the consistency of oatmeal, and acts more like a lead based
    metal.

    I was wondering if any other jewellers have been plagued with this on a recent job?

    Jim
    Last edited by jimzim75; 04-17-2008 at 02:01 PM.
    I never get tired of talking, joking, arguing, discussing, a subject that holds our attention most of the day. Engraving.

    Jim Zimmermn
    Hand Engraving Canada ~-~-~-www.handengravingcanada.com

  2. #2
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    Default

    Jim I've been using carbide for the precious metals. I put a mirror finish on the face and heel w/ 200,000 mesh. I spray it on my ceramic wheel then wipe it off with a tissue before polishing. It seems to work very well for me it might work for you also.
    I used a white alloy from United that was #930 and didn't like it very much. It was supposed to be for torch melts but I didn't have much success with it. I was getting very porous castings with hard spots. It's probably the casting and not your gravers, but a polish carbide may help burnish over the porosity while cutting.

  3. #3
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    Default

    Hi Mike,
    Same here, as far the carbide and mirror polish.

    This is a issue that has been going on for years.
    What's best to set in vs. what best to cast with. Since I don't own Au and a lot of jewellers in Detroit
    use them. I don't think things are going to change much. So it's going to have to come down to having
    a separate set of bright cut gravers to deal with the mushy/hard alloy. Oh boy.

    You could get palladium white gold but the a whole other can of worms. Plus the customers are getting
    nervois enough about the cost of the standard white gold. Let allone a premeum alloy cost.

    I though about burnishing the sufface but this is a deep bright cut and I don't think it would help that
    much.

    I don't know, maybe annealing it a couple of times might even it out.

    I'll let ya know.
    Talk to ya later,
    Jim
    Last edited by jimzim75; 04-17-2008 at 02:03 PM.
    I never get tired of talking, joking, arguing, discussing, a subject that holds our attention most of the day. Engraving.

    Jim Zimmermn
    Hand Engraving Canada ~-~-~-www.handengravingcanada.com

  4. #4
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    Default

    I don't know Jim annealing may make it worse by making the grain structure even more loose. If you could compress the area to be engraved maybe with a hammer it may tighten up the grain structure but not very likely because you would be addressing the surface more than anything else. Heat treating may work, like 600 degrees for so many hours or something like that. Maybe the maker of the alloy can tell you the temps needed to harden the metal. Do you notice any hard spots in the metal especially when you polish?

  5. #5
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    Default

    Hi Mike,
    This stuff polishes to easy. It more like polishing yellow gold. I found out the first time I set it, the
    hard way. So that means setting the diamonds and polishing the tips lightly. Then once it's been
    bright cut never touching it with a buff again. I had to re-brite cut the last peace because of it's soft
    nature.

    The thing about it, is that when your bright cutting it. Areas go frosty and then go back to high brite
    polish again. This has to be the erratic form of the alloy distribution. I think Au uses a magnetic
    stirring unit on the induction machine. I think this alloy just has a tendency to migrate into different
    zones. That's why my comment that it seems like oatmeal.

    I have a feeling that if you rolled it to half it's thickness and change the molecular structure enough, it
    would be a bad gold to set in. This was a CNC wax so they could save time on the bench.

    Unfortunately I think this is the type of process that is fast becoming the rule.
    So I'm just going to have to deal with it. I think I'll make that my new motto.

    Talk to ya later
    Jim
    "I just have to deal with it".
    Last edited by jimzim75; 04-17-2008 at 02:04 PM.
    I never get tired of talking, joking, arguing, discussing, a subject that holds our attention most of the day. Engraving.

    Jim Zimmermn
    Hand Engraving Canada ~-~-~-www.handengravingcanada.com

  6. #6
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    Default

    TRy a 25 degree heel,and try polishing it on a leather strop with diamond dust,slightly rounding out the heel angle.

  7. #7
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    Default

    Thanks for the suggestion, Silverchip. I will try it.

    Jim
    I never get tired of talking, joking, arguing, discussing, a subject that holds our attention most of the day. Engraving.

    Jim Zimmermn
    Hand Engraving Canada ~-~-~-www.handengravingcanada.com

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