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Cleaning small metal parts.

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  • Other: Cleaning small metal parts.

    Acting on a recommendation from Bob Kapteyn, I took a shot at cleaning a bunch of small rusty and/or greasy parts in a cement mixer with caustic soda solution.

    First part of the job was to rehabilitate an ancient cement mixer I bought from a local farmer. Welded some skids and wheels under it, made up a motor mount to support the old washing machine motor, and put a handle on it so I can trundle it around. The drum turns at about 34 RPM, if anyone is keeping score. I had to chip several pounds of hardened cement out of the drum.

    The first go-round I dumped in two boxes of miscellaneous fasteners and small parts from the dismantling of several long-departed Studebakers. I had a 20 liter pail of caustic soda pellets; once. Now I found a 20 liter pail with a cylindrical block of solid caustic soda with a quart or two of thick syrup on top. I poured off the caustic syrup, and added it to the drum of the mixer, along with a bucket of water.

    This rig works amazingly fast. After less than an hour of rattling around in the mixer, the parts were visibly pretty clean. I poured off the now-brown caustic solution into a pail, added fresh water to the drum, and ran it for a minute or two. Repeated the rinse, then dumped the parts out into a tray, rinsed them again with fresh water from the hose, and dumped them out on plastic table with an old sheet draped on it to dry in the sun. Had to pick a few chunks of undissolved caustic out of the first batch.

    Did another batch, while I did a first-order sort of the first batch. "Bolts, nuts, washers, everything else." "Everything else includes Studebaker clutch push rods, manifold clamps, spark plugs, and spark plug wire looms, amongst numerous other parts. Even some plastic parts, like interior door lock buttons and washers for behind the interior door handles. Fished one aluminum part out of the first batch; it was trying to dissolve. An oil filler cap for an older VW; sure came out clean.

    Result: nearly all the parts were wholly or largely cleaned right down to bare metal with a matte finish, ideal for taking paint. A few of the parts have areas where a thin, smooth coating of rust persists, but not nearly enough to prevent them from being used. The parts are all clean enough to be worked with, every last one.

    Some parts, I will undoubtedly throw away, because the threads are damaged, but from prior causes, not from the tumbling.

    I took some pictures:
    Attached Files
    Gord Richmond, within Weasel range of the Alberta Badlands

  • #2
    This brings a new meaning to the can of "Mixed Nuts."


    • #3
      Last edited by new2drive; 05-14-2012, 05:10 AM.


      • #4
        Thanks for the chemical advice. I actually have given some thought to disposal. What I will do, if given a green light is haul the pail of spent caustic solution to a wellsite where they are drilling with water-based mud. They add caustic soda to the mud in copious amounts to keep the pH at 10 or better, so dumping a pail of caustic solution into the mud system would be like spitting in the ocean. Whatever heavy metals may be in the sludge will be spread through the tons and tons of rock cuttings, which have their own natural background of heavy metals.
        Gord Richmond, within Weasel range of the Alberta Badlands


        • #5
          Maybe you could also use the rocks from a Deburring machines and add a soap solution.
          101st Airborne Div. 326 Engineers Ft Campbell Ky.


          • #6
            Polishing tumblers and stones work well too. We have 6 different ones here. The stones we use are specific to the different types of metals. You must be careful to not mix them up as some will work and soem won't... it really depends on the metals. For example, you can use ceramic or plastic stones for aluminum, but not plastic for metals. If you have any questions, shoot me a pm.

            I cannot contribute much to the forums "car mechanic" wise, but I am a fuel and additive specialist, including oils, metalurgy and chemical compatibilities. Sometimes this is a great resource when dealing with "modern" vs "old" materials.... like what elastomers (rubber) to use and when or using detergent oils vs non detergent, ZDP issues, etc...


            • #7
              I spent an hour or so yesterday morning sorting parts from the second batch put through the cement mixer. Old spark plugs cleaned up well! Brass and copper parts cleaned up very bright, but you can tell they are slightly etched, as though they had been bead-blasted.

              The solution has little or no penetrating power. Bolts that had nuts tight on them going into the soup, came out with nuts tight on them, but the exposed threads were clean.

              Best thing about this process, in my mind, is that it enables me to clean up old grungy hardware in bulk, in a very short period of time. I have a few more boxes and coffee cans full of parts ready to clean, and then I will have to root around in the many "miscellaneous boxes" for more to do. The cleaned parts are sorted in 4 categories as described above. Further sorting by size and thread type can wait for some Winter evening, when I can sit at the bench and putter.

              By the way, it sure does clean up the drum on the old cement mixer!
              Gord Richmond, within Weasel range of the Alberta Badlands


              • #8
                I also use an old cement mixer to clean small parts. But use a very heavy course ground quartz. It works well time and time again.

                62' Deluxe R2 4SPD.

                63' R1 Wagonaire

                57' Transtar 259 punched to 312 NP540 4:09 TT Under Construction

                58' 3E6D Stock 4X4

                64' (Studebaker Built) Trailer Toter


                • #9
                  For small rusty parts, Evaporust is good stuff. And it's safe too.
                  '59 Lark VI Regal Hardtop
                  Recording Secretary, Long Island Studebaker Club