No announcement yet.

Circulation or aeration?

  • Filter
  • Time
  • Show
Clear All
new posts

  • Circulation or aeration?

    I bought the 2 gal zinc plating kit and I guess I was expecting that it came with the required pump but I see that wasn't on the list. In reading the manual plus numerous posts I see references to circulation of the fluid as well as aeration.

    Is there a preferred method?

    Are there any issues with available aerators and/or pumps to be aware of?

    If aeration is better, can that be simply achieved with my source of compressed air?

  • #2
    The best aeration I have found over years of trying all kinds of arrangements is to use your shop air compressor and a good filter/dryer (to keep any oil film from getting in the solution) and run LARGE air bubbles.

    It would be safer to use a high end fish tank pump (or oil-less type air compressor with reserve tank/regulator) if you have any doubts as to the quality of the air in your shop.

    The arrangement I have rotates the parts in the solution and a single air hose (3/16" I.D.) is weighted down with a piece of stainless steel pipe to hold it in position in the bottom of the tank.

    I use (2) large anodes on both sides of my 2-gallon round tanks.

    A single stream of LARGE bubbles is all I use. The LARGE air bubbles agitate the solution quite nicely. Note that the PSI is about nill. It does not take a lot. My 60 gal. compressor turns on about once every (4) hours when plating.

    Notice I stayed far away from those airstones which (in my experience) did not work near as well as a single stream of LARGE air bubbles.

    A side benefit of the LARGE air bubbles (believe it or not) is they don't make a mess out of you plating area. The airstones (with their tiny bubbles) create a mist that gets all over everything.

    George W
    Orlando, FL


    • #3
      Thanks for the info George. I will set up something similar this evening. Do you just leave the hose open ended in the bottom of the tank?

      And may I ask why you use 2 anodes?


      • #4
        Yep, open ended hose.

        In my experience, using (2) anodes allows a higher deposit rate and thus a shorter time in the solutions or an increased deposit for the same amount of time using just (1) anode.

        For copper and nickel I always run (1) hour in the solutions.
        Lays down .0015" to .002" of plating per hour.

        Don't go out and but another anode just yet.
        Get some experience under your belt and experiment.
        It took me over a year to fine tune my set up and tecniques.

        The best things I discovered were the LARGE air bubble aeration and the automatic part rotating device I constructed.

        See by web page below (go to the plating page near the bottom).
        I really got to update the photos, have a lot more stuff to shoot.
        Note that I did not have the air hooked up in the photos.
        The pictures were taken quite some time ago prior to my Large air bubble discovery.

        Keep in mind I mainly plate acid copper, nickel and Copy Chrome.
        I'm sure you will have the same result with the zinc.

        George W.
        Orlando, FL


        • #5
          I had seen your page some time back, very good work. I also see you're using a larger power supply with your setup. I have one much like that as a backup if the supplied unit is inadequate. I like your rotation setup, may look into that after some practice.

          Do you know if the other forum member (can't remember his id) that was trying to do zinc and having difficulties ever succeeded? He did the fairly extensive testing of effects of various currents and voltages and photograph the results?


          • #6
            Yea. I just was wondering that myself.
            Would have liked to see some photos as you mentioned.

            Seems like he never got back on the forum to let us know how it went.

            A friend of mine in SC has used the Caswell Zinc and he did not indicate he was having any real problems.

            One of these days I will have to order the bright zinc kit so I can have some first hand experience with it.

            Minor ranting time:
            OK Mike Caswell....when are you guys going to offer the 1 quart "chepo" $25.00 starter kits as I suggested about a year ago?
            Just a quart of solution, an anode and a single instruction sheet for the specific kit.
            It would wet the appetite of many to get into the hobby and make you more $$$$$.
            Ranting over.

            I was toying with the idea of getting the bright zinc some time ago during the "64" Puch motorcycle restoration, however, decided on sticking with he nickel and Copy Chrome since I already had all the stuff and there would be no learning curve.

            The "Auto-rotator" is pretty simple to make. Look into it when you have some time.
            The good thing is you don't ever have to mess with the parts while plating.
            It allows you to do something else while plating.

            I decided to get my power supply (0-18V, 0-10A) because I knew I would be plating a lot of parts and just wanted to do it right.

            Too bad Caswell did not have the 20amp one they now offer when I bought my 10amp for the same darn price (about (2) years ago from another source). It is dead identical to mine except twice the power.

            Let us know how you are doing on the zinc.

            George W.


            • #7

              I'm interested in your LARGE air bubble aeration technique.

              Most of us over in the Anodizing Forum dislike aeration because of the sulfuric acid mist generated; but as far as I know, we have only used very small bubbles. I'd like to know more. When you say LARGE bubbles, how large? What's the approximate diameter of a typical bubble?

              Many of us are using agitation, circulating the electrolyte at a high rate (5 gallons at 420 GPH in my case) which generates no mist at all and provides outstanding results. Agitation is particularly advantageous when its combined with an electrolyte temperature control / cooling system, I use a 1/4 HP chiller in series with the agitation pump. Electrolyte temperature above 75 deg. F. is bad in Anodizing, I know that most plating is done at higher temperatures, but this method would also provide very even electrolyte heating as well.


              • #8
                I use a single 3/16' I.D. airhose so I would imagine the bubble size is at least 3/16" in diameter.
                Can't give you a psi reading on the regulator since it is too low to even register on the gauge.
                Seems to be about 10 bubbles per second coming out of the hose.

                As I had mentioned in a previous post, the larger air bubbles just don't make a mess of the work area.
                Of course the acid copper and nickel don't have any noxious odors so there were no fumes when using the airstones.
                I just did not like all the splatter that was getting all over my work area and I am getting a much better plate (with no pitting what so ever) on the surfaces because the large air bubbles wipe off any small hydrogen bubbles on the surface and provide some real good agitation.

                Wow, 420 gph sure is a lot of agitation. You must have some big tanks!
                When using my home built horizontal tank (for long slender items) I have a small built in D.C. powered pump that puts out a wimpy 10 gph.
                Works fine however.

                I always run my plating solutions at "garage" temp. (75 to 95 degrees).
                In our "cold" Florida winters I will put a heater in to raise the temp. to at least 75 degrees.

                George W.


                • #9
                  Wow, 420 gph sure is a lot of agitation. You must have some big tanks!
                  In anodizing at least, if all of the electrolyte stays in the tank, you can't have too much agitation. My tank uses 5 gallons of electrolyte, at 420 GPH it cycles all of it every 43 seconds. The chiller allows me to anodize at 32 deg. F, with over 300 Watts being dissipated in the tank. I need this because I've been fooling around with Type III (Hardcoat) anodizing. That means applying 35 Amps for 90 minutes with my size work. This level of agitation and cooling capacity is necessary for good hardcoat.


                  • #10

                    i use a tiny little $8.00 "small fish tank" aerator. The bubbles are better than the "misty" bubbles but not quite that large. I too have found larger bubble better but have not gone that far... gotta give that a try.

                    On a side note... i wish i tapped into this forum a long time ago... lots of experience and tips here.


                    • #11
                      Make sure you use a check valve in the line, or else during a power failure all your solution will siphon out, or place your pump above the tank.


                      • #12

                        Do you know if the other forum member (can't remember his id) that was trying to do zinc and having difficulties ever succeeded?

                        Seems like he never got back on the forum to let us know how it went.
                        Maybe that was me? If so....

                        I've never left the forum, but I did have to suspend my plating activities for a few months. Been mostly lurking w/occasional post & questions.

                        I have posted recently after caswell asked for "SUCCESSFUL PLATERS - YOUR DATA NEEDED". Y'all must have missed it. Check it out for latest data:

                        My web pages & photos are still works in progress, but I’m updating them more often right now. Some recent changes, noted in the call for data from caswell:

                        Meanwhile, what I’ve found works best for me:

                        1) forget the small power brick: It’s too difficult to adjust all the parameters to get the desired current density, and you can’t plate more than a tiny handful of parts. Since I went with a CC power supply, all works well.

                        2) current density: 80-100 mA/sq-in. The numbers in the plating manual are not entirely correct. The 25mA/sq-in figure is based on the power bricks RATING of 300mA. Divided by 12sq-in gives you the 25mA figure. However, in actual plating use, the power brick delivers 700-800 mA, at about 0.4v. Thats’ approx. 58-68 mA/sq-in. The correct current density range for the electrolyte is 65-150mA/sq-in. The power brick falls below the low-end.

                        3) temperature: keep it low, 60-70ºF. I aim for 65º.

                        4) electrolyte agitation: I'm using aquarium pumps, and they work fine. Trying to plumb in all that PVC piping in a small bucket just seemed to be over-the-top, not to mention needing a compressor. The pumps are cheap and easy to work with. See the videos on the web site:

                        5) “Bright” vs “Black” zinc: these 2 are NOT COMPATIBLE with each other. If you plan to blacken the zinc, you need to use unbrightened electrolyte. I’ve got more pictures on this, will post soon.

                        6) Blackener temperature: 100-110ºF. the parts will blacken faster w/better looking finish. It’s still not a durable finish though.

                        I’ve got some new pictures, hope to upload them to the web pages today or tomorrow. Token image of some parts I did yesterday:

                        Seans Zinc Plating page


                        • #13
                          This thread got me off my butt. New web pages & pictures just added:

                          Seans Zinc Plating page


                          • #14
                            Thanks Sean, a wealth of very valuable information. And the pictures are great, good quality workmanship there in those parts.