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  • Interesting surace treatment

    At work over the years we have bought and sold surplus replacement parts for various types of machinery. Some of the parts dated from the 40's and 50's and had a hard sort of a slighttly opague finish that doesn't come off with solvent, or allow any rust. I've spent some time off and on trying to figureout what it was over the last couple years and finally in a chance encounter with an old fella that worked machining parts for slurry pumps I finally got some clues.

    He said they would clean and degrease the parts, then coat them with some Cosmoline which they had thinned down with Kerosene. After the excess had dripped off they would bake them in an oven at 525-550F for a couple hours. Apparently the heat drives off any residual moisture and bakes the Cosmo on hard.

    So I made some more tee nuts recently and figured they might be good to experiment on. I didn't have any legit Cosmoline, but I did have some LPS 3 which shares some distillates and parafin bases so I thought I would give it a try. I degreased, bead blasted and dried the parts, sprayed on a good coat of LPS and blew the excess off with light compressed air. Put them in the heat treat furnace at work and waited a couple hours.

    The result looks similar to what I used to see, maybe a bit lighter in color, but is unaffected by solvent and is even tough to come off with emery. Now obviously this might not be a good idea for heat treated steels with a low draw down temp, but for everything else you just don't want to rust, it might be the ticket.

    I plan to try it at lower temps and see if the result is the same. If it is, then even heat treated items would be fair game.
    Attached Files
    Last edited by wierdscience; 01-02-2022, 12:48 PM.
    I just need one more tool,just one!

  • #2
    Also given the color of the finished product, it appears to prevent oxidation from taking place during the bake since normally those temps would produce a violet/blue hue.
    Click image for larger version

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    I just need one more tool,just one!

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    • #3
      I wish we could edit titles
      I just need one more tool,just one!

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      • #4
        I've heated parts almost red and dropped in oil and got the same results.

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        • #5
          Originally posted by wierdscience View Post
          I wish we could edit titles
          I did not notice the misspelling until you mentioned it. Funny how your brain can fill in the missing letters and unscramle phrases on the fly.

          What steel do you use for your t-nuts?
          Tom - Spotsylvania, VA

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          • #6
            Not so different than the old "Japan" finish, the chemistry is similar but the temps are 2x higher. FWIW, you can still buy the genuine Cosmoline in quart cans: https://www.cosmolinedirect.com/mil-...caAr33EALw_wcB

            I know the "baked on" finish you are talking about, they are pretty indestructible. Don't see it very often nowadays, though.
            25 miles north of Buffalo NY, USA

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            • #7
              Looks similar to finishes I’ve done using boiled linseed oil, Japan drier, and heat. Stuff left outside doesn’t rust. As far as I understand it - the BLO polymerizes when exposed to oxygen. the heat speeds the process. It creates a thin, flexible, soft layer that protects the iron. YMMV.

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              • #8
                Originally posted by wierdscience View Post
                I wish we could edit titles
                I had to read it 3 or 4 time before I saw it. :-) Actually spelled each word . :-)
                ...lew...

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                • #9
                  Wierdscience

                  Oh well blew your chance of going the whole year without making a mistake.
                  Blame it on spellcheck.

                  Hal

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                  • #10
                    What is it with the spelling and grammar these days, do people just not know how to spell or do they just not care anymore?

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                    • #11
                      Originally posted by vectorwarbirds View Post
                      What is it with the spelling and grammar these days, do people just not know how to spell or do they just not care anymore?
                      Three things: Typing on a tiny, on-screen keypad and a lot don't know and don't care.
                      Southwest Utah

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                      • #12
                        Originally posted by challenger View Post
                        I've heated parts almost red and dropped in oil and got the same results.
                        Me too, that's more of a combination of carbon layer and oxidation though I think. Normally when I quench 1045 and then do the draw in the furnace I get a deep blue oxidation color, which I like. This is different, the steel stays bright and all of the color comes from the Cosmoline.
                        I just need one more tool,just one!

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                        • #13
                          Originally posted by wierdscience View Post
                          I wish we could edit titles
                          I was able to edit the title. Did it just a couple weeks ago. I do remember when the forum software was first updated you couldn't. I had asked George at the time and he said no way to do it.

                          JL..................

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                          • #14
                            Originally posted by flathead4 View Post

                            I did not notice the misspelling until you mentioned it. Funny how your brain can fill in the missing letters and unscramle phrases on the fly.

                            What steel do you use for your t-nuts?
                            I got some really odd 1045 flatbar I picked up at at scrapyard years ago. It's 1/2 x 1" but has a bull nose radius on both edges.
                            I just need one more tool,just one!

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                            • #15
                              I think CAT bolts are coated with some phosphate. They look like black oxide but the dealer said otherwise. I've seen some hardware that looks to have a clear anodizing type finish, not sure what that is either. Clear parkerizing ?
                              The blackening looks good in your T-nuts.

                              JL...............

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