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"Hard" Anodizing vs. "normal"; differenc

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  • "Hard" Anodizing vs. "normal"; differenc

    And which is Caswell's LCD kit capable of doing? Would it require heating the part after treating? If the kit's process can do both, then what differences in the process should one do to "hard" anodize as opposed to the way listed in the manual's LCD supplement? I have a potential customer base who was very insistent on having their parts hard anodized, because they had problems with rock chips on motorcycle swingarms before with other anodizing processes. Also, is there any limitation as to what colors can be used in the "hard" anodizing process? Sorry for so many questions to the moderator and everyone, but I want to make sure the LCD kit will do what my potential customers are wanting (assuming I follow the instructions from Caswell's manual) before I put my money into it, or make them any promises I can't keep. Thanks.

  • #2
    The LCD and hard anodizing are different. Hard anodizing requires higher voltage and a colder anodizing solution, which generally would mean a chiller. The high voltage will add more heat to the solution than either standard or LCD anodizing, which means the chiller needs even more capacity to keep the temperature down from standard anodizing. By using a large tank relative to the part, and limiting the amount of power dispersed to a modest level you can get by without a chiller when doing standard and especially LCD anodizing. With hard anodizing it's not much of an option. All anodizing needs the temperature to be controlled, standard and LCD works in the 65? - 75? range and if the anodizing process raises the temperature too much beyond this a chiller is required also.

    You could learn the hard anodizing I am sure with time, research and investing in the required equipment, but as far as buying a kit and immediately turning out large top quality jobs is probably not too likely. I don't know of any hard anodizing kit available either.

    Hard anodizing colors are typically limited to dark colors like black and dark green, as the anodizing process leaves a dark color, and it's hard to dye light over dark. The only required heating of the part after anodizing is sealing it in boiling water, although I understand there are various approaches with hard anodizing according to the requirements, such as corrosion resistance.

    It may be that unless your volume justifies the investment, that sending the parts out to a commercial hard anodizer. Another solution to protect the color might be to clear powder coat over standard anodizing that can give a very attractive look.


    • #3
      A little background information: The LCD kit (and most other methods popularly available on the internet for DIY anodizers) will give you a Type II anodize, usually in the 0.0002"-0.001" range. Standard Type II anodizing usually operates around 12-15 A/ft^2, but the LCD method has been modified to operate at around 3-6 A/ft^2, thus minimizing the size of power supply necessary (making it cheaper).

      A 'Hard Anodize' is designated a Type III anodize. Here's some of the ways it differs from type II anodizing:
      • Type II acid bath temp is usually around 68-74F. Type III acid baths need to be kept around 32F.
      • Type III acid baths usually are less concentrated than Type II. I don't know specific concentration values, but the 1:3 mix of LCD should work well for both.
      • Type III current density is usually between 24-36 A/ft^2.

      The 2 main thing you'll need for Type III anoding is a large chiller to keep your electrolyte solution cold and a much larger power supply. I believe you will need at least 60 volts, possible more, to truly get a hardcoat. So, if you're looking to anodize 1 square foot pieces with both methods, you'll need about a 0-5 amp, 0-12V power supply for LCD and at least a 0-24 amp, 0-60V power supply for hardcoating. You can see that the power supply will be MUCH more expensive. I doubt you'll find that kind of power supply for less than $1000.

      If it's worth it to you, you might do some further looking into it. For most of us small guys, we generally send out any Type III work to a larger shop.


      • #4
        wow M_D, that was a quick reply, and nearly identical to mine! I feel like a copycat now.


        • #5
          Type III also requires very vigorous electrolyte agitation, much more than standard Type II or LCD.


          • #6
            Originally posted by NeoMoses
            wow M_D, that was a quick reply, and nearly identical to mine! I feel like a copycat now.
            I would have proof read and corrected all of the grammer mistakes in mine you would have easily beat my post time.


            • #7
              Thank you

              Thank you all for your input. I've been doing quite a bit of research into the differences in the processes, and the power supply will be the biggest expense. I almost got one off eBay (60V and 100A) for $340, but it was a 440V set-up and the expense of trying to get the other electrical support (not to mention the inherant danger in working around 440V, which I used to have to do while working as an apprentice electrician) was enough to convience me for now to start out with type II anodizing and chroming, which I should be able to hopefully do with my new power supply (a Kepco JQE15-50, 15V 50A power supply) and then IF the customer I mentioned still wants me to also do type III work for him, then as long as he wants to front the money for the additional equipment as a deposit on work to be done, then fine. But otherwise, it may be more expense than the work it produces would justify, especially for what is starting out as a small garage-based hobby-business.

              Have any of you had any luck using a clear powdercoating over a type II anodized surface, to give it an extra degree of protection from rock chips, etc.? Might not be AS tough as type III, but might it be a good compromise? Or not?