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CASWELD Our new 'Welding' rods

Introducing our latest range of Welding and brazing rods, for the repair of Pot Metal, Aluminum, Stainless and much more.

Please see our web page for details.

http://www.caswellplating.com/restor...ding-rods.html

These products replace the range of Muggyweld and Technoweld products we used to sell.
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PLATING POT METAL...............

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  • PLATING POT METAL...............

    Thought I would pass on what ive learned over the last year or two about plating pot metal.
    It is probably the most difficult (but not impossible) metal to plate.
    If you have any hair....take it out now!
    To start with you have a zinc based metal that was of no specific alloy or make up. Then add to that about 40 or 50 years of corrosion and it gets frustrating.
    But...as I said, it can be done.
    The way I deal with it......and there can be other ways. is to first
    Sandblast the part really, really good.
    This does three things...
    1 Removes the chrome. (you will see it spark as it comes off)
    2 Etches the nickel and gives the strike plate a good foot to plate onto.
    3 Exposes and removes some of the corrosion from the pits.
    Take your part out and blow it off with air.
    You most likely have a part that looks like it belongs up in space floating around now.
    Dont dispair!
    Next I clean off about 2 square inches of the surface with a wire wheel in a 1/4 die grinder. Make it all shiny.
    Then take a drill bit or dremal tool and drill out each pit down past that little black dot of corrosion thats in the middle of them.
    Now for the fun part.
    All those little pits have to be filled and smoothed out.
    I use a zinc based solder and flux that melts at 340 F. Its tricky to use but works well.
    Fill each pit, wash and sand smooth. Repeat this until the part is totally smooth.
    I sandblast the part again after this. Just lightly.
    Dont touch the part with your bare hands after this. Use nitril gloves..not latex or rubber.. They will leave a residue on the part
    I now put on my robbers to protect the High current areas. Put the wire or heavy piece of copper on the part that will hold it to the cathode bar.
    Make a little jumper wire that goes from the cathode bar to the part. This will allow you to enter the STRIKE bath live.
    You want to go into the strike bath live and at the highest amperage setting you can without burning the part. This does two things.
    1 Gets the plating on as fast as it can so the bath doesnt react to the zinc based metal
    2 Makes the bath throw down into the Low current areas better.
    After about a minute like this take the amperage back down to what you figured out for the part.
    This will take some practice on some SCRAP pieces.
    After you are satisfied with about 15 miniutes of the strike bath rinse your part off and go directly to the acid copper for at least a hour.
    I usually go 90 minutes on the first acid copper plate.
    After the acid copper, rinse the part off and start sanding it smooth.
    DONT sand down to the original potmetal. If you do, continue to sand the rest of the part, rinse off with plain water and into the strike bath to restrike it.
    Use gloves when your sanding so you dont get the copper all over your hands and you dont get your finger oil on the part.
    Continue to sand and copper until it is smooth. I sometimes have to copper plate 5 times to get all the pits removed.
    Once it is smooth I then work up from 180 grit to 400 grit sand paper and then buff, clean, nickel plate, rinse and then chrome plate.
    Like I said.....PRACTICE on scrap pieces...dont take your good parts and ruin them.
    I hope this helps shorten the learning curve for some of you.
    Pot metal is a mutha......but it can be plated successfully by the hobbiest plater. It just takes time and patience...........lots of patience!
    Now you know why the plater groans when you bring potmetal to them!
    48 Buick

  • #2
    Thanks 48,
    I have some old car parts (50s) that are pitted, scratch, and basically ugly. A couple nights ago I was ready to give up on them. I am printing your post off and adding it to my notebook. I know a guy that does sandblasting, but he takes a while to get things done. Looks like I need a blasting cabinet now. My wifes gonna kill me. LOL!

    I am quickly learning that the plating kit is just the "clearcoat. Its all in the prep.



    f&^% hobbyplating.com

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    • #3
      Bryan:
      The biggest thing with potmetal is to just stick with it until you learn how to deal with it. Its the hardest metal to plate.
      Practice a lot on scrap.
      Good luck and let me know if you need any advise.
      48 Buick

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      • #4
        48 Buick,

        Thank you, your explanation answered my burning pot metal question, do you use bright acid copper plating for filling reasons after the stike coat, especially with pitted parts? Your explanation clearly says yes.

        My son and I are working to restore a 52 Plymouth Cranbrook with, you guessed it, plenty of pitted pot metal chrome. I ended up purchasing the Copy Chrome/Flash Copper Combo Kit and a starter buffing kit, but still have a way to go before getting started. Now I'm debating getting the bright copper plating kit and the zinc based solder you mention. Can you advise me on a source for the latter?

        Steve47170 :P

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        • #5
          Steve:
          When I deal with potmetal, first I sandblast the part to clean it up.
          After that I determine how much metal I can remove by sanding without destroying the detail and profile of the part.
          For deep pits I will fill them. Sand some more, refill low areas, sand, ......ect. The other pits that are 1/16" deep or less I will use the acid copper to fill.
          Your definently going to need acid copper. You may have to plate it 3-4 times with sanding inbetween.
          Crystler products are a pain in the rear!!! Thier potmetal always seems to differ in its alloy. I have a 55 Dodge that gave me fits.
          But, it can be done with patience.
          I think Caswell sells some stuff called solder it that may be used to fill the pits and plate over
          48Buick

          Comment


          • #6
            Thanks a TON 48, for your posted procedure (25 NOV '03) this was like a GODSEND as I've been fighting with this 60 year old bathroom faucet ****.......(I mean stuff) for weeks.

            YOU DA MAN!

            I am still unclear on your definition of "robbers" however, or the particular application you describe. The manual I have, (version 4) describes a "robber" as a way to reduce current, or rather "spread" the current out to ultimately reduce delivery to the work piece.

            I do remember reading somewhere how to reduce edge build up by "pig-tailing" wires out from the edges, but I can't remember enough about it to do me any good, or even where I saw it.

            Could you please explain how this is done?

            Comment


            • #7
              Hi:
              A robber is simply a piece of copper wire that protects a high current area.
              By this I mean that a pointed part on a item will conduct a lot more current then a flat or recessed area. This will cause the pointy area to burn.
              The robber has to be electrically attatched to the part itself. That way it will act as a higher current area then the place your trying to protect. This will also allow you to increase the current if you have some low current areas that are not getting much plating.
              Basically the robber takes the hit of the high current and the part plates more uniformly. Robbers usually grow funny growths on them and burn..that is normal.
              Shields will do the same but are a reverse of a robber. They protect areas by blocking it off from the current and allowing other areas to plate either faster or as normal.
              Hope this helps.
              48BUICK

              Comment


              • #8
                Thanks 48........

                I have these "escutcheons" (I think I spelled that right) from an old set of bathroom sink handles that are rather bell shaped, which have to be hung "bell-end-up" to prevent bubble entrapment. I guess I would just rig sort of a "spider" affair of copper wire, attached to the cathode wire that would rest on the open end of the "bell", to protect that edge?

                Thanks for your help!

                Dave

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                • #9
                  Re: PLATING POT METAL...............

                  Hey everyone i am having a problem.....OK i have a 83 Honda V65 Magna i am restoring and there is lots of pot metal to do.......well i have the flash copper, acid copper and copy chrome. The Flash copper works good but when i go from the flash rinse and go into the acid copper, the acid copper doesnt cover the entire part and it looks like ****.......i wire wheel the part, sand some areas smooth, wash with dawn, soak in SP degreaser and into the flash copper at high for one minute and then down to the normal amps for that part, the rinse and into the acid tank. So then it comes out crappy. Both tanks are at room temp. cuz i have tried heating but after i finish with flash and go into acid it bubbles. i tried (hot) flash and then ruff part up and into sp greaser to put into acid but the flash copper was bubbling too after that.............so if anyone can help........much appreciated...

                  Shawn

                  Comment


                  • #10
                    Hey Shawn, are you sure it's pot metal? Which parts are you trying to plate?

                    Sounds like you've got aluminum. If that's the case, you'll need some zincate solution. Maybe check Caswell's site on "Aluminum Processes".

                    Hope that helps!

                    Good luck.......

                    Dave

                    Comment


                    • #11
                      Dave i am sure its pot metal........i did a acid test........and it fisses and bubbles on the part..........aluminum does not do that....but like i said flash copper sticks too the pot metal but the acid copper will not stick to the flash copper......it flakes off...........any ideas....

                      Comment


                      • #12
                        I would say that any adhesion problems you're having between the flash & acid copper is due to surface contamination. I don't use SP degreaser on ANY white metal (aluminum, pot, etc.). Soft scrub works the best. And use purple nytril gloves. Latex or rubber will leave a film or deposit on the part and it won't plate properly.

                        I run my flash copper at 110-120 degrees, and acid copper at 75-80.

                        Dave

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                        • #13
                          dave, if u have copy chromed pot metal before.....would u mind explaining ur techique on how to do it...step by step......just to try another avenue........and i was running both my tanks @ about 90 but both of them,flash and acid were bubbling, so by Caswell advice try running them at room temp........so with the flash its working well i think @ room temp. but i am not to sure about the acid copper......

                          thanks once again.

                          shawn

                          Comment


                          • #14
                            Hmmmm...

                            OK, here's what I do:

                            1 - De-grease with soft scrubb, rinse with distilled water.
                            2 - Sandblast the beegeebers out of it.
                            3 - quick rinse with distilled water to remove sand residue.
                            4 - flash-copper @.05adc for 1 minute, then @.03adc for 1 hour.
                            5 - remove from flash - rinse (distilled water) - acid copper for at least 1 hour at .03adc @75-80 degrees.

                            Good luck!

                            Dave

                            Comment


                            • #15
                              Dave....what is the biggest part u have done(any pics either) and what do u use for a setup......just curious.......and when u flash copper..........is it room temp or higher......well if u use a sandblaster........it leaves pits in the metal right...........do u have to do any filling in(soldering) or does the copper fill it on in....just trying to get a grip on all of it..........from the flash to the acid do u any cleaning or scrubbing or ruffing....or just straight into the acid tank..........
                              Just to make sure...........these steps are for u doing pot metal right?
                              Thank you so much

                              shawn

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