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  1. #61
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    sag, can you say more about your solution?

  2. #62
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    Quote Originally Posted by dian View Post
    sag, can you say more about your solution?

    Sure thing: It's not enough to just heat mineral oil and dissolve raw sulphur into the solution, that only stays in solution for two weeks before crystallising out again due to poor solubility. It does work and has active sulphur evidenced by blackening copper, I then found a patent (US patent 2549525) for sulphurised cutting oil made from rapeseed oil (canola). I substituted Hexamine with it's six methyl molecules for the original dicyclohexylamine with it's ten methyl molecules.

    It's turns out that hexamine is a crosslinker for making phenolic resin and in my experiment it worked too well: the canola and sulphur is a liquid when warm but cools to a rubbery solid. It dissolves in all mineral oils to form an excellent sulphurized cutting oil. The oil turns copper black from active sulphur and reams stainless beautifully as a slightly blunt squealing reamer goes quiet and reams easily. It does however, condense back into a rubbery solid over six months or so (commercial products do this too). I then made a second batch ( recipe in the second video) with the changed formula of less sulphur which remains a liquid at room temps and doesn't condense into a solid, I use 10% of it in oil instead of the original 5% and have has no problems since. It is a highly concentrated liquid so you add one part to nine parts oil to use it. It lets me recycle of my waste hydraulic oil to get a second use out of it and costs bugger all, compared with the fastener shops price of $60 per quart bottle.

    Making the recipe should be done outdoors with a cover over the reaction pot due to the hydrogen sulphide smell and in my case, made my neighbour run around all over the place looking for a sewer leak. Here's two more entries in the Youtube Machinist bun-fight:


    Last edited by SAG 180; 04-23-2017 at 04:42 PM.

  3. #63
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    Here is the part two video with a corrected formula in the comments section that stays in solution long term:


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  5. #64
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    interesting. why dont you just dip the tool in the concentrate?

  6. #65
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    Quote Originally Posted by dian View Post
    interesting. why dont you just dip the tool in the concentrate?

    I'm just using the approximate ratios mentioned in the original patent, having a higher sulphur content may not improve performance and may have side effects like the thick solid gel that formed in my earlier batch when the sulphur content in the concentrate was higher. I think the performance doesn't get any better with the higher amounts: if there's enough sulphur to form the metal-sulphide films during machining then it's done it's job.......I could be wrong as I haven't tested it. I use the sulphurised lard at full strength as it doesn't seem to have as high a sulphur content as the canola oil: more smelly sulphur compounds were formed when it was made so less organic sulphur compounds were formed and it was orange in colour instead of the dark red-black colour of the canola.


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