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So I tried out rust bluing

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  • So I tried out rust bluing

    The rusting part works fine.

    The conversion part is causing trouble. The rust just does not convert very well to black rust (Fe3O4). I have boiled the part (that same turret box tool) with only a small part of the rusted areas turning black even after extended boiling. It always looks fine in the water, as if something is happening, but out of the water, the water evaporates off the part, and it shows up red. "Carding" it does nothing to change that. Wet, it looks dark, of course.

    I thought the rust bluing process was fairly foolproof, but apparently not so much.

    The result of several cycles......red rust OK, black rust very spotty, if indeed that IS black rust.




    Last edited by J Tiers; 10-13-2020, 08:22 PM. Reason: Fixed senior moment about formula on black rust
    1601

    Keep eye on ball.
    Hashim Khan

  • #2
    Life is full of little disappointments..... But for real, there are some alloys that tend to put up a really tough fight against bluing actions. I've come across a multitude of parts and materials that refuse to be blackened by any means, although they are able to rust. One was a old piece of mystery round stock that was clearly rusted and pitted on the outside, but once I machined a part with clean surface out of it and tried to blue it, there was literally zero effect. The surface came out of the bath clean and shiny without a spot of red or blue, as if was stainless steel. So go figure...

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    • #3
      For information red rust is hydrated ferric oxide Fe2O3 and black oxide coating is ferroso-ferric oxide Fe3O4

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      • #4
        try a pressure cooker, maybe?

        so i wonder what is really happening. you artificially rusted it so you had what? FeO(OH)+Fe2O3? what does it do in water? being reduced to FeO x Fe2O3 (Fe3O4)? that works for Fe2O3 but what about the rest? how else could you reduce it?

        what did you rust it with? i would think it depends on what you had in the first place.

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        • #5
          Rust bluing has worked for me the times I've done it. I used fume bluing (put the part in a container hanging from a wire with some acid) and a special carding rotary brush. Rust, Boil, Card.

          I would try another piece, perhaps the steel in question is the problem.

          EDIT:
          This article hints that the water might be the problem
          https://www.americanhunter.org/artic...do-it-at-home/

          I've just used tap water.

          I've read that some people keep reusing old rust bluing water with all the remains in it.
          Last edited by DennisCA; 10-13-2020, 06:11 AM.

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          • #6
            Perhaps select various scrap pieces, of varying heritages, and simultaneously subject all of them, along with your intended target piece, to the same process, and see if they all turn out the same. Harder pieces of metal have always appeared to me to be noticeably more rust resistant. That's usually a good thing, but probably NOT SO if your aim is rust bluing.
            Lynn (Huntsville, AL)

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            • #7
              Water chemistry causing issues? Maybe, although it does make a hard black "shell" of magnetite (Fe3O4) on steel when doing the electrolytic "rust removal" method (which I now know better than to try again). We have hard water.

              I suppose I could try that method with the INTENT to produce a hard black shell. But I fully expect that for THIS piece it would remove rust, and leave that perfectly clean metal that folks always laim is normal for electrolytic removal!

              Originally posted by DennisCA View Post
              ....
              I would try another piece, perhaps the steel in question is the problem.

              .....
              Ah, well, the particular piece is the part I want blackened...... I don't care if some other piece is rust blued. I may have to do what I do NOT want to do, which is use the oil method.

              I have recently found that oil quenching does almost as good a job as the "black heat" oil blackening method, so that is a possibility.

              As you can see, however, there are areas that have in fact blackened, so it is not as if the steel cannot be blackened by the rust method. It just does not work fast or evenly.
              1601

              Keep eye on ball.
              Hashim Khan

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              • #8
                I've been having the same problem. Parts come out of the boil nice and rusty. Frustrating, the parts are much worse than before I started.
                It's all mind over matter.
                If you don't mind, it don't matter.

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                • #9
                  I've done rust bluing before. A bit time consuming. But everything I did came out fine.

                  One thing I found out is don't waste time putting a high polish on anything because the process etches it back down to about a 320 grit finish.

                  If you want a high polish finish you have to go hot blue.

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

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                  • #10
                    Originally posted by JoeLee View Post
                    I've done rust bluing before. A bit time consuming. But everything I did came out fine.

                    .................
                    So, how many times through the boil did it take?

                    Did each time result in an improved blacker finish all over, or did it start patchy?

                    What was your rust creating material?

                    What steel alloys did you use?
                    1601

                    Keep eye on ball.
                    Hashim Khan

                    Comment


                    • #11
                      This is the stuff I used............... https://www.brownells.com/gunsmith-t...-prod8795.aspx

                      I repeated the process about 8 times I believe to get the desired color. It was simple and my test parts came out real nice. I was unhappy about how it takes a high polish surface finish down to a non glare finish.

                      Almost like a soft bead blast look. Not what I was looking for. I tried several types of steel. sheet and round stock.

                      I also tried nitre blue. that was pretty but not what you would want to do for tools at 600 degrees.

                      You've tried a few back yard concoctions and all have given you horrible results. Unless you have some unknown alloy there which I doubt I would suggest you look for a local gun smith shop that does hot blue and ask them if they'll throw it in the tank next time they fire up. Polish it up good and see what happens. You've put yourself through a lot of aggravation so far.
                      But I've been there too.

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

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                      • #12
                        Originally posted by JoeLee View Post
                        ..........

                        You've tried a few back yard concoctions and all have given you horrible results. Unless you have some unknown alloy there which I doubt I would suggest you look for a local gun smith shop that does hot blue and ask them if they'll throw it in the tank next time they fire up. Polish it up good and see what happens. You've put yourself through a lot of aggravation so far.
                        But I've been there too.

                        JL.................
                        Where's the fun in that?

                        I can get a great black any time I want to fire up the torch.... I could have this part black in 20 minutes. That's really not the issue. I see no reason not to try stuff, that's what we do here.

                        I am just NOT into "checkbook machining", that should be fairly obvious from the various tooling projects I have posted or sent to the magazines..... so I have no issues trying 10 different methods. The point here was to try the methods. I'd do hot bluing if I had the AN.

                        Not sure I would call them "backyard concoctions", as in each time I have followed procedures recommended by more than one reasonably reliable source. ALL of these methods are "odd concoctions" if it comes to that.

                        And, I am not intending to get at you personally, but if it disturbs you, you are free to not read about the trials of the methods..... I have no problems doing the trials, and reporting results. If I can stand it, I reckon most can either read or not at their choice.
                        Last edited by J Tiers; 10-14-2020, 11:27 AM.
                        1601

                        Keep eye on ball.
                        Hashim Khan

                        Comment


                        • #13
                          I tried that AN and water mix (from the other thread) the other day on a few parts. Some blackened very well and some didn't. These parallels for instance turned out great. Some parts from an old surface gage that looked like they had been color-case-hardened did not. To be fair I didn't bead blast them before trying it either though. Click image for larger version  Name:	20201014_131024.jpg Views:	4 Size:	694.9 KB ID:	1904813
                          Last edited by eKretz; 10-14-2020, 02:48 PM.

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                          • #14
                            So after reading this thread, I decided to give it another try. I used the peroxide/salt solution. I treated the parts a total of 4 cycles: rust in the solution, rinse with cold water, boil, then dry and brush the loose rust off with an old toothbrush. By the fourth treatment, the reaction became noticeably less vigorous. Before oiling, the color was more plum brown than black. Here's the finished product, before and after oiling.

                            Click image for larger version  Name:	image_13258.jpg Views:	3 Size:	1.26 MB ID:	1904871

                            Click image for larger version  Name:	WP_20201014_14_36_44_Pro.jpg Views:	86 Size:	1.09 MB ID:	1904875
                            Last edited by MrWhoopee; 10-16-2020, 12:53 AM.
                            It's all mind over matter.
                            If you don't mind, it don't matter.

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                            • #15
                              Not what you were asking for but maybe it will open the can of worms just enough for you to try some things.

                              This was heavily rusted orange so I didnt mind messing it up. I degreased in oven cleaner for a day then soaked the hatchet in a bucket of must for rust. Over soaked it to the tune of a week.

                              I knew it would be black, only thing I dont like about this stuff.

                              I washed it real well with the green scrub pad a dish soap then sprayed it with wd40. It does not come off with normal use. JR

                              Click image for larger version

Name:	hatch.jpg
Views:	170
Size:	1.49 MB
ID:	1904895

                              My old yahoo group. Bridgeport Mill Group

                              https://groups.yahoo.com/neo/groups/...port_mill/info

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