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Thread: Platinum Alloy Help

  1. #1
    Join Date
    Jun 2020
    Posts
    8

    Default Platinum Alloy Help

    So I had the wise idea of making a platinum engagement ring and a couple of wedding bands... I've never done any jewellery making before, but I do work in electronics and am an amateur blacksmith, so the world of small metallic things is hopefully not all too alien to me!

    One very deep rabbit hole later and I'm getting close to giving it a go, however I do have a big problem and that's the material itself. I could read forever and not get an answer, so I thought I'd ask on here to try and expedite things...

    From what I can gather I like the sound of a 90/10 Pt/Ir mix, I can buy pure Platinum easy enough, but where on earth can I get my hands on 3g or so of Iridium?

    I don't really like the idea of the Pt/Co on Cooksongold, as that seems to be more of a casting mix, and about 25% more expensive than buying the constituent metals.

    Another cost is having to buy a sheet of solder, but I've read just a thin piece of the alloy heated in the joint will work with Pt/Ir?

    I don't know, I despair, I hope someone can help, I understand the complexity of this craft, but it surely shouldn't be this hard to find information, there don't even seem to be relevant books to buy.

    Also the fear of carbon contamination, but I'll leave that for another thread I think!

    Cheers in advance.

  2. #2
    Join Date
    Dec 2009
    Location
    Central London
    Posts
    8,845

    Default

    Hi, Beer and welcome to the forum.
    There are members who can help you with this (not me), but keep on looking. Dennis.

  3. #3
    Join Date
    Feb 2011
    Location
    Scotland
    Posts
    3,392

    Default

    Hi from me too
    Can’t help either.Most of us buy sheet or wire to make rings, it makes life much easier. No doubt someone will take up the challenge.

  4. #4
    Join Date
    Mar 2011
    Location
    Manchester UK
    Posts
    937

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    Usually platinum is hallmarked 950 so you will need to meet that assay. I'm not sure you mix will. Platinum cobalt is nice to work in its very malleable, you can also tell its coolt because it magnetic. I like to cast with Platinum Ruthenium its nice and white. You can fuse platinum without solder but it requires a bit of practice. I've never worked with Iridium but I guess you can buy it from bullion dealers as stated above I usually buy my metals ready made so I don't need to worry about assay

  5. #5
    Join Date
    Jul 2009
    Location
    Romsey
    Posts
    5,256

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    Iridium has a melting point of 2466C. Pt90Ir10 has a MP of 1800C.
    Yes, you can weld platinum rather than solder it; it's a different technique and takes some practice to get right.
    Johnson Matthey published an extensive book - available as a PDF - on working with Pt. It's still around but it'll take some locating.
    https://www.amazon.co.uk/MJSA-Press-.../dp/0971349509 - again, if you can locate it.

    There's a number of reasons why platinum is not a beginner metal.

  6. #6
    Join Date
    Aug 2019
    Location
    Oxfordshire
    Posts
    231

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    I haven't worked with platinum but I'm also interested.
    I haven't been able to locate the book but there are a few articles by the same author:

    https://jtf.it/images/pdf_archive/JurgenMaerz_EN.pdf

    https://www.ganoksin.com/article/pla...ation-factors/

    And one from Johnson Mathey:

    https://johnson-matthey.ch/pdfs/prep...bench_work.pdf

  7. #7
    Join Date
    Jun 2020
    Posts
    8

    Default

    Thanks all for the input, really nice to not be alone on this! I'll have a good read from those suggestions.

    Josef, as I won't be selling the pieces I didn't mind not reaching the 95% purity, and I quite liked the idea of Iridium as I'm a bit of a materials nerd and it's rarity and density holds a bit more of an allure to me than Cobalt! But it seems I will only reasonably be able to buy it by the ounce while I only want 3g, so perhaps I just have to scrap the idea and use Pt/Co. From what I've read it is not as easy to work with and doesn't harden to the same level, but maybe I'm nitpicking.

    The plan is to mainly forge one of the rings (the others simple milled bands) and they'll all only have one joint just where I close the band, I'm hoping if it's straightforward simple joint I'll be able to use a bit of the Pt rolled flat...

    I know it's really not ideal, perhaps I need someone local to hold my hand through the process, but I can't really afford to spend 6 months researching and practising and I've made my mind up to give it a go now!

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