A Disappointing Purchase

It’s been a while since I posted anything. I do have several partly written, but I just haven’t had the motivation to finish them. So I thought I’d just put up a quick one today.

I bought this aluminum plate with a thin layer of green resin on the surface, which was claimed to contain “12000 grit diamond,” from AliExpress. I did some testing with it on my S110V Spyderco Para Military 2 and was surprised and disappointed to find that the hone wasn’t cutting the vanadium carbides in the way I would expect.

To investigate, I sawed off a small piece of the hone for analysis. A cross section through the resin layer shows that there is plenty of abrasive, although they are too large to call “12k grit.” Also, these are some very unusual shapes for diamond particles…

SEM image of the resin cross sectioned and polished by focused ion beam.

Next, I did elemental mapping on that surface, to see what the various materials are.

Elemental maps of the resin cross section.

There are three distinct materials in the cross section. The sharp-edge particles are revealed to be silicon carbide. The dark region between them shows carbon and oxygen, as expected for polymer resin. The small, bright particles are chromium oxide, explaining the green colour of the resin. I don’t see any diamonds.

  18 comments for “A Disappointing Purchase

  1. Tobias
    February 3, 2021 at 11:06 am

    is it a DMD?

    Like

    • February 3, 2021 at 11:09 am

      That’s the problem. Is it a genuine DMD, or did I get a counterfeit knock-off?

      Like

      • lim chuan huat
        February 4, 2021 at 10:48 am

        there shld be some lettering on one of the sides

        I have an extra piece and will ship to you a piece that I bought from DMD direct. do give yr address

        Like

        • February 4, 2021 at 11:22 am

          I think you mean like this:

          As with all of my posts, there are more images and analysis than I discuss, as I am cautious to confirm the results I present. In fact, I purchased 3 DMD diamond resin hones from two different AliExpress stores nearly a year apart. All three are composed of silicon carbide with little or no diamond.

          Like

          • TOGITOGI
            February 7, 2021 at 6:17 pm

            In Japan, there are several such kind of sintered diamond sharpening stones and which costs more than USD150 any one.

            I searched and found a sharpeningstone with such print. It was cheap, seemed to be made in China, and I couldn’t figure out what manufacturer made it.
            There are many fake products in the world.
            I think investigating for such products is a waste of time and effort.
            I hope you will investigate about the grindstones that are highly regarded by carpenters.
            https://www.naniwa-kenma.co.jp/sharpening_stone/diamond/

            But unfortunately these products are not found in the lineup for the market in EU/USA/CANADA/AUSTRALIA
            https://www.naniwa-abrasive.com/product/sharpening_stone/index1.html

            Like

  2. Josh
    February 3, 2021 at 11:06 am

    Wow, so cool to be able to verify these things. Hope you are doing well Todd!

    Like

  3. Mark Stump
    February 3, 2021 at 11:07 am

    China?

    Like

  4. Eric Sprehe
    February 3, 2021 at 11:11 am

    I’d act surprised, but… Well, you know…

    Sorry that happened to you Todd. I hope it was cheap at least. Too bad you can’t return it at high velocity through their car window. =)

    –Eric

    Like

  5. Andr3w
    February 3, 2021 at 11:12 am

    You should post a review on the purchase site with this link. It will go down in history as the most in depth review of all time.

    Liked by 1 person

  6. keyresults
    February 3, 2021 at 11:41 am

    Hoping it was isolated incident or counterfeit prod. A real bummer in any case. Sorry u got burned. Many thanks for the heads up Todd.

    Like

    • February 3, 2021 at 12:12 pm

      I purchased the 3k version too and it is also mostly silicon carbide; however, I did find a couple of diamonds in that one.

      Like

  7. February 3, 2021 at 2:07 pm

    No one expects the SEM-EDX!

    Like

  8. Leith Murray
    February 3, 2021 at 8:00 pm

    As consumers I believe we are being lied to on many fronts.
    If a product states that it’s a diamond sharpener, I believe it is expected
    That the majority of the product (excepting the base which it is applied to)
    Is Diamond, not glue or a b c d e.

    Like

  9. D M Dave
    February 4, 2021 at 2:46 am

    There is a store on aliexpress which sells only DMD items. Maybe you can contact them.

    aliexpress.com/store/5023099?

    Like

  10. February 7, 2021 at 5:59 pm

    Thanks for sharing, much appreciated.
    There is a lot of information about a lot of things ‘out there’.
    Finding good information is like finding 12000 grit diamond in a Chinese stone claiming it.
    Thanks again

    Like

  11. Philipp rein-e-art
    February 9, 2021 at 8:27 am

    Thanks for sharing, happy to see you got active again πŸ™‚

    Like

  12. elguy
    February 13, 2021 at 9:15 pm

    Hi,
    Any “household” tests for diamond detection?

    Also, FWIW, grey text on grey background is greeey πŸ˜‰

    Like

    • February 14, 2021 at 10:50 am

      Not that I can think of, other than perhaps the performance on high vanadium carbide steel.

      Interesting, I hadn’t noticed that the body text had switched to dark grey from black. I made the mistake of subscribing to wordpress.com for 3 years, so I am stuck with their awful editor for a bit longer.

      Like

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