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Calculating surface area / Odd parts

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  • Calculating surface area / Odd parts

    Hello. I've read up and down these forums and haven't found a definitive method/answer.
    so ill be running LCD method, with the same bath concentration recommended, TI wire, running a nice hefty rectifier at 6ASF, trying to achieve 1mil.

    My question is.. When using the 720 rule, how in the world do you accurately measure the surface area of a part that has lots of bends, twists, holes and areas impossible to measure?

    Ive heard some anodizers say they just blast the amps, max volts and run for an hour, but that doesnt seem like it would yield consistent results.

    i thought I have read somewhere that once 1mil has been reached, your voltage changes? Is this the best indicator to shut off power once the volts start to drop?

  • #2
    If the area is impossible to measure, then you can't measure it and you need to do something else. However, is it necessary to be 100% accurate on the area? No it's not. If your area calculation is off by 10%, then your coating thickness will be off by the same amount. So if you are targeting 0.7 mil for a dyed part and you are even 20% off then you will get 0.56 - 0.84 mil and the part will still be fine. The biggest issue about not knowing the area is running too high of a current density and burning the part. I would certainly not recommend "blasting the amps...max voltage". This may work, but in more cases than not you will damage the part.

    If you do not know the area, and you have no way to get it, then run by voltage. In commercial shops we see Type II parts run around 12V-14V for 20-25 minutes and the current just goes where it needs to go. I'm not sure how that would correlate back for an LCD setup though.
    Last edited by KevinB; 12-04-2019, 03:05 PM.
    Process control doesn't give you good quality, it gives you consistent quality.
    Good quality comes from consistently doing the right things.

    Process control systems for Anodizers
    If a post helps you out LIKE the post
    I'm not an Amateur Metal Finisher. I've just been around the industry for a dozen years or so helping and consulting when and where I can.


    • #3
      Its primarily paintball markers I plan on doing. The twists, turns and cutouts is what makes it challenging. The bodys have multiple tubes milled, so id guess id need the surface area of the internal tubes aswell as the external surface area.


      • #4
        While the LCD method has it's place it's meant more for the casual home user. If you want to make it easy for yourself (and dead simple) go with 12ASF / 180g/L electrolyte. It's what all the job shops use.

        The process is dead simple. Submerge your parts, set your amperage to max and slowly dial up your voltage to 14V +/- (once you've proven your 12 ASF initial test). Run for one hour with good agitation maintaining 70 deg tank temp and the parts will draw the required amperage on their own regardless of their complexity in shape.


        • #5
          Very nice. Id like to pick your brain gardinhackle. So you have fb messenger?


          • #6
            yes I do....I'll send you a private message with my info. Look at the top right of your screen


            • #7
              sorry to jack the thread but gardinhackle would you be able to assist me in a few things? or Draz if you've gotten the information needed about the paintball parts would you mind helping a brother out?