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Anodizing Power Supply Q's

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  • Anodizing Power Supply Q's

    I am in the process of setting up our shop to anodize some of our products on a small production scale, and I have some questions regarding power supply requirements. I just received the "new" LCD anodizing kit, and I plan to start "playing" pretty soon!

    For starters, let me say how impressed I am with the site, and with the products I have received so far. Truly top notch!

    I think I jumped into this in the middle of a revolution of sorts. When I first started researching this process about 9 months ago, power supply requirements were a bit different:

    At that time, I downloaded a PDF file from Caswell, Inc's website, and the basic message was: "Unlike other plating procedures, where the amperage has to be controlled. . ., Anodizing will only draw whatever current it needs from the power supply".

    Currently (no pun intended. . .), the message is different, where something to regulate current is favored (as in plating). Obviously, the messages contradict each other, so I'm left wondering what to do. I don't think the physics have changed, although the methods have.

    I wanted to use a "Switching"power supply I have, regulated to 13.6 Volts DC, up to 30 amps. I used it in the past as a substitute for a car battery when charging R/C car batteries.

    Is this power supply suitable to use with the updated kit? Also, why the change in methods? Just curious.

    Thanks in advance for any info you can provide!!


  • #2
    Rest assured that Mike Caswell and I are in no conflict here at all. As a matter of fact, it was Mike that involved me in the first place, because you guys were having so many problems. Contrary to what some may think, Mike does care, and he intended me to be the vanguard of the solution.

    I can't think of a nice way to say this so I'll just say it; nearly every set of instructions on small scale or hobbyist anodizing that you'll find are incomplete, technically flawed, or just plain wrong. It appears that the authors found one of many recipes that happened to work for them, and then never bothered to figure out why it worked. If its any consolation, you would be shocked to know how few professional anodizers actually understand how and why their process works. That said, LCD does work. If dyeing quality is of importance, LCD will outperform conventional techniques, even those used by pros. But should you choose to anodize at conventional current densities, the simple and very effective mathematical techniques explained in LCD will work equally well.

    Power supplies that are battery substitutes are not generally fully adjustable, which is a drawback. You will need to provide information on the maximum size part you intend to anodize, and some idea of it's total surface area before I can advise on the size of power supply you will need.

    The idea that anodizing is somehow "self current limiting" violates Ohm's Law, and hense is wrong.


    • #3
      Thanks Fibergeek,

      I hope my post was not taken as a negative "slam" on anyones part, especially Mike's; that was definately NOT the message!

      I think I was just confused by the apparently contradictory information I found, and I was hoping for some clarification. I also spent MUCH more time reading through the manual, which cleared up the concept of LCD anodizing. I appears that LCD anodizing offers a more stable process, and produces a higher quality, more repeatable dye result (if I understand correctly).

      I think I'll be able to use the supply I have with the LCD process, I'll just have to reduce the current rate somehow. For starters, I'll try using light bulbs, which seems fairly easy. I'll move on to a supply with more current control in the future if things pan out.

      Thanks for your help, I'll let you know how things turn out!



      • #4

        If you're going to use your 13.6 V 30 A switcher, you will have to use light bulbs or power resistors. The lamp dimmer method will only work on an unregulated power supply like a battery charger.

        If you look at the anodization curves in the technical reference at the rear of the LCD instructions, you will get an idea of how much and how soon you will need to change the number of light bulbs. Using the curves for 3 A/sq.ft. as an example; it seems to me that you will want maybe 3 light bulbs in series at startup, and as the process continues, short out one bulb, and then the second, within the first 15 minutes. The third bulb stays in the circuit for the whole anodization time, as it provides the final current limiting. I've never used this light bulb method for current limiting (seems to be too much work to me) since I always use a real current source for anodizing. You will have to do some experimenting. If you need help figuring out which bulbs to use post that here. The information you will need to supply is:

        1. The surface area of the piece you are anodizing.
        2. The current density you intend to anodize the piece at.
        3. Assuming 12 V automotive bulbs, the current or wattage of the bulbs you want to use.

        BTW, MSC Industrial Supply ( has a cheap digital multimeter on sale for $6.95. This unit will be adequate for monitoring the voltage and current. To monitor the current, you will need some sort of a 0.1 Ohm power resistor, at least 10 Watts in size.


        • #5
          Well, here's MY 2 cents (pennies) worth!

          When we started this business, we looked at the numerous methods of doing plating/anodizing and tried to pick the one's that looked the simplest, with the widest operating range. We tested them, found them to work, modified and simplified the instructions, and made a kit.
          It was that simple. (Actually in was a complete pain in the rear!)

          As time went on, our customers fed us titbits of information and gave us different slants on doing things. We didn't waste this info, but took it and immediately improved our kits. What you see today, is over 12 years worth of customers tips.

          This anodizing system is one of those improvements. In my opinion, Fibergeek has given us a HUGE leap forward in anodizing.

          I'm hoping that I shall see NO PRS tech support problems and receive no phone calls for technicals support!

          I HAVE BASS TO CATCH!!!!
          Mike Caswell
          Caswell Inc

          Need Support? Visit our online support section at


          • #6
            Fibergeek -

            Thanks for the advice, and I think your're right, the method you describe would be kind of a pain in the rear, at least for anything other than experimentation, which is exactly what I need to do!

            Actually, after reading the info in the manual regarding LCD and VCCS supplies, it seems to me what you are looking for is a voltage-peak detection supply. When voltage stops rising, and begins to fall, that would indicate the process is complete. I used to "play" pretty seriously with R/C car racing, and the chargers we used for the batteries are peak-detector chargers. I wonder how they would work in an anodizing circuit? They might be too sensitive, but it could be worth a try.

            I'll get some of the info you need together to see if I'm working in the right direction regarding lamp circuits.

            Mike -

            I completely understand where you are coming from. I manufacture a kit (actually a few) that work with the Ford Powerstroke diesel engine to improve fuel system performance, and our kits have gone through several "generations" to get to the stage they are in. Hopefully, your Anodizing products are going to make them that much better

            I fully respect the level of development in your products; after comparing with what else is available, the work you have done to create a quality product shows! And, please keep in mind, I've only got my system partially working yet!

            Thanks again, you guys are awesome!!

            Also - How did the BASS DO


            • #7
              I need to provide some clarification here:

              I can't think of a nice way to say this so I'll just say it; nearly every set of instructions on small scale or hobbyist anodizing that you'll find are incomplete, technically flawed, or just plain wrong.
              This is me further up in this thread. This does not imply any sort of lack of diligence, competence, or anything else bad on the part of Caswell Plating or it's associates. When the standard instructions were developed, it was done based on the best technology and technique available at the time. There are very many of you who have been using the standard process for years and are enjoying perfectly good results. This is proof enough of the standard process. I avocate that you add the LCD monitoring techniques; like PAR, to your particular method. You will find things will get a lot easier, and your results will be even better.

              The idea that anodizing is somehow "self current limiting" violates Ohm's Law, and hense is wrong.
              Me again. This statement is technically correct and I can prove it. I can see how it can look this way under a narrow range of operating conditions, if you ignore what happens at anodization startup. Unfortunately, its at startup where correct current limiting counts the most. This does need to be fixed.

              Also for the record:
              No one put me up to posting this, I re-read the thread and realized how it had been taken. My apology to Mike. He has been busting his butt for you guys for years, I hope you appreciate it.

              (edited to fix a typo)


              • #8
                Back to anodizing.


                Regarding a peak detection method; a method of peak detection that is dead S L O W is required. This isn't easy to do with analog peak detectors, I was thinking about a software method. At the lower LCD current densities, if it takes you less than maybe 15 minutes to decide that the peak has been reached, you are going too fast, and might be fooled. Look at the time scale in the anodization curves.