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First Anodizing Project - Would love some feedback on what I did right / wrong

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  • First Anodizing Project - Would love some feedback on what I did right / wrong

    Hi all!

    I have to admit, I've been lurking a while as I planned out my first project (1911 7075 Frame) and I've love some feedback on what would make my next project better.

    I tried to setup an anodizing rig with what I had laying around. I think the only thing I ended up purchasing was the dye, Ti wire and some battery acid. I already had the buckets, beakers, lead, misc pumps and power adapters laying around from several other projects. I Frankensteined together a setup that I hoped would give me a decent result. Two tries, both using the same basic formula, different results but both acceptable.

    First attempt was with a small grip safety of shiny 7075 aluminum. I had problems keeping good electrical contact (constantly having to "fix" the contact after turning my back) so I'm not really sure of how long it was kept under voltage. However, I loved the outcome. Silver or dull grey with a slight matte finish. Fantastic!

    Second attempt was with my 7075 aluminum frame, just as shiny as the safety. Made sure that the electrical contact was constant and it ran for ~55 minutes. The outcome however was a bit different. The appearance was a light bronze and no matte finish. It did however take dye very well with only a small blemish on the handle that was almost completely covered with the grip plate.

    For both I used a 50/50 mix of Napa battery acid and distilled water. Parts were pre-rinsed with distilled water, cleaned with dish soap, rinsed, degreased and then rinsed again before being added into the acid bath. Parts were connected via Titanium wires. I used large lead sheets as the cathodes with a foil bridge external to the tank. To charge the tank I used an 18vdc/5amp power supply I had laying around. Less than desirable but available. I used that power supply on both attempts.

    On my first attempt I used a small beaker without an attempt at temperature control. The unit, when I had good contact, produced a lot of bubbles and mist. I'm guessing full contact time at about 10-15 minutes with the surface area totaling not more than a few square inches. Again, the part came out matte grey and I sealed it as-is in boiling distilled water.

    Second attempt, large beaker in a salted water bath kept everything at about 60-65F. I used an old aquarium pump to keep the cool water flowing. Same beaker setup as the first attempt just larger. I also used an old aquarium air pump to keep the acid solution moving but made sure the hose was away from my frame. Using the same power supply there were a lot less bubbles and mist (makes sense) but they were constant. When I took the frame out had a light bronze coloring. Actually quite nice and I might do this again and just leave it with that color. I however gave it a quick rinse and into the dye it went. After the sealing it came out with a dark solid dye. Again, only a slight blemish but otherwise nice. It was a bit shiny and I was hoping for a more matte finish (both pieces started out the same as both were shiny and polished aluminum). Not matte but I really wasn't disappointed as it came out better than I had hoped.

    Questions. I "believe" I followed the 720 rule (sort of) for my frame although I guessed and fudged a bit here and there. Anyway, 55 in-sq @ 1mil @ 6 amp/ft = 2.3 amp / 15vdc @120 minutes. Yes? My volts were a bit higher and I doubled my amps so I figured 55 minutes should be the time. How far off base am I here? My thought about the first piece being matte is that I perhaps went way over on time and perhaps under timed my frame?

    Is matte finishing normal for longer burn times or over voltage/amps? Could I have gotten the frame to a matte finish if I went longer or ramped up the volts/amps? Is the bronze coloring normal for a Type II anodizing?

    I'm really happy with the way it turned out and I'm going to be doing this again with my next build but I'm just trying to tweak what I've already got without spending more than I'd like on a project that's just for fun. If anyone has any constructive criticism - or just plain criticism, I'd be very happy to hear what I got right, what I got wrong, how I might better do it next time and what I just plain fraked up.

    Thanks for reading!
    (in case the pics didn't come across - here's a link to a few showing both pieces and my tank setup)
    Frame with Anodized Safety Dyed Frame

  • #2
    Bueller, Bueller, Bueller?


    • #3
      Burgess, there's a lot going on with your setup that will cause inconsistencies in output. If you plan to do this more than just as an experimental thing then I'd suggest picking a platform (LCD or 12ASF) and learning it. Buy the proper chems and mix to the proper levels and follow time/dilution/procedures diligently. I use the 12 ASF format but Caswell sells a great kit for the home user and I'd suggest you look into it. That way you have some support for your question, for which you will have lots.