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riviting parts and rust prevntion

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  • riviting parts and rust prevntion

    My latest project is a 1/6 scale British 4.5" Howitzer with a great deal of riveted parts. It is mainly made of 18 Gauge (0.045") sheet steel that will be riveted (round head rivets not pop rivets) together like the original.

    Now for the big question.

    Since it is made from steel and while not exposed to the elements it may still rust, even when painted. I have been painting the parts that are to be riveted together, on the faces that will be joined with primer, with the hope that that will help prevent rust from forming between those faces and working its way out. Is there anything that would be better then primer??? The model will be completely painted when finished so any kind of oil or grease is out of the question because it will ruin the paint job.
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

    Southwestern Ontario. Canada

  • #2
    Maybe start with galvinized sheet?
    Nev.

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    • #3
      I have used cold solder before on exposed spots on galvanized bolts, works like a charm and it should not give any problems when you paint over it..... Oops just read your post again.... Cold solder for the small spot but not practical for the entire sheet... Not sure if your local supplier stocks it but how about a NS4 anti rust paint on the bare metal..actually it even works a bit better if the metal already has some rust on it..... The NS range does have primer as well but have never used it...
      Last edited by Westline; 02-25-2017, 05:26 PM.
      If you are using violence and it does not work, You are not using enough or it is upside down.
      You can always just EDM it...

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      • #4
        Originally posted by NiftyNev View Post
        Maybe start with galvinized sheet?
        Sorry but galvy isn't an option for other reasons. Cut edges would rust anyway.
        Last edited by loose nut; 02-25-2017, 06:10 PM.
        The shortest distance between two points is a circle of infinite diameter.

        Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

        Southwestern Ontario. Canada

        Comment


        • #5
          Originally posted by Westline View Post
          I have used cold solder before on exposed spots on galvanized bolts, works like a charm and it should not give any problems when you paint over it..... Oops just read your post again.... Cold solder for the small spot but not practical for the entire sheet... Not sure if your local supplier stocks it but how about a NS4 anti rust paint on the bare metal..actually it even works a bit better if the metal already has some rust on it..... The NS range does have primer as well but have never used it...
          I thought about tinning the joint areas with solder. I'll put it on the short list.


          Industrial paint isn't really an option either,I live in a small town and I don't need a large quantity, a few ounces at most, so I'm limited to what I can find locally. Rustoleum etc.
          Last edited by loose nut; 02-25-2017, 06:11 PM.
          The shortest distance between two points is a circle of infinite diameter.

          Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

          Southwestern Ontario. Canada

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          • #6
            Primer doesn't protect from rust; you need a primer/sealer. Like:

            DUPLI-COLOR DPP103 Primer, Sealer, 12 oz. available at some auto parts stores or from the internet.

            Mike

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            • #7
              Agreed, standard primer does little against rusting.
              Parkerize the parts. Super easy, cheap and looks great. I would think that it takes paint well too.

              http://bbs.homeshopmachinist.net/thr...rize-Something!

              There are also other threads with additional information.
              Location: North Central Texas

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              • #8
                Parkerizing or bluing or other treatments don't prevent rust on their own. They act as a surface that better holds oil. That's why it's used on firearms. To better hold an oil film.

                I'd suggest you coat the edges after drilling with a thin wipe of boiled linseed oil. A THIN coat left over night or for 24 hours in a fairly warm place will polymerize just fine and produces a thin varnish like layer to resist rusting and it will bond well to most primers and paints that are not lacquer based. If it is still sticky after the 24 hours then you left too much on.

                I've been coating my garden tools after use with a 50-50 mix of boiled linseed and mineral spirits. Just a very thin wipe down that barely leaves it wet looking is enough to prevent rust despite storing the tools in an open shed through even the wettest season. Prior to using the BLO mixture they would rust badly.

                The coating isn't very durable so each time the tools are used much in sand or other abrasive material it needs re-coating but the good part is that dirt slides off it well instead of sticking in clumps like it did to the rusty shovels.
                Chilliwack BC, Canada

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                • #9
                  It depends a great deal on the primer. Ordinary thin gray automotive etc. primer will often rust through. But, for instance, the yellow and red Rustoleum anti-rust primers act more like a paint, and I have not seen them rust through unless the rust was not cleared out to begin with. They probably classify as primer-sealers.

                  If you eliminate coatings, and don't like galvanizing for some unknown reason (why?*), it does not leave a lot of options. So some sort of coating is probably in order.

                  Hit the parts with good old red lead primer before assembly, you won't have an issue....and it will likely be just like full size practice....

                  Boiled linseed oil on the parts will do a good job of sealing. It does not count as oil, since it will polymerize just like paint.

                  Most paint-like coatings would be rubbed off in the riveting process, and then there is the question of the rivets, will THEY be painted as well? I assume you will cold-set them, as hot setting would destroy any paint coating. You are bound to get some bare areas from the assembly process, if you demand a perfect coating, tinning is likely best, although even it will not be perfect.

                  Riveted bridges with hot set rivets seem to stand the test of time, so you likely are worried about things that will not actually be an issue.



                  * the effect of galvanizing would probably work right down into the rivet holes. It has some "throw" capability.
                  CNC machines only go through the motions

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                  • #10
                    I think I would go with a zinc rich primer, you could coat the mating faces before assembly, then the rest of it after assembly. It might be worth looking into copper rivets, they won't rust and should be easier to cold set.

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                    • #11
                      I think it depends on where you life, how humid it is. Even so you are doing a lot to keep it from rusting with the paint. After the paint is dry and cured good you could put a small amount of oil in the seams and maybe it would wick into the joint if the paint has left any opening. After a few days wipe off the excess oil.

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                      • #12
                        This may be a little out there, but what if you dip the steel in copper sulphate to give it a thin copper plating?
                        Location: Long Island, N.Y.

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                        • #13
                          Step one: make it rust evenly on purpose. Step two: use a phosphoric acid rust converter to make a tenaciously ahereing iron phosphate coating. Step three: primer. Step four: paint.

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                          • #14
                            If this is a model, why not make it with aluminum instead of steel? Will it see some kind of rough use?
                            Paul A.
                            SE Texas

                            And if you look REAL close at an analog signal,
                            You will find that it has discrete steps.

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                            • #15
                              Originally posted by Paul Alciatore View Post
                              If this is a model, why not make it with aluminum instead of steel? Will it see some kind of rough use?
                              Best idea yet, Paul... but one better, use brass sheet and brass rivets
                              Joe B

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