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Anodizing project

Discussion in 'METAL FINISHING, CUTTING & WORKING' started by Bob S, May 21, 2013.

  1. Bob S

    Bob S Active Member Active Member

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    I just started anodizing in January and have done a couple hundred parts for a robot I am designing. Here is a photo of one of the legs for a hexapod along with an plain test version of the leg.

    I did it primarily in black with some parts having gold highlights. My system uses commercial dyes, 4 hot plates, heated degreaser and heated Nickel Acetate for a sealer. The anodizing bath itself is just a shallow plastic tub that has about 5" depth and 21" length. The cathodes are 2 lead sheets on opposite sides, a single aluminum hang rail with several SS Allen screws for connections. I also use titanium wire to make all my electrical connections. I also use bubble wrap floating on the bath to reduce the amount of misting since I use air for agitation.

    This setup has been pretty reliable with few issues on the anodizing end. I've been really pleased with the end results and plan on doing a lot more anodizing in the future.

    image.jpg
     
  2. autonoz

    autonoz United States Active User H-M Supporter-Premium

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    Looks great. I just today set up a small trial anodizing system. I am currently anodizing a small aluminum cutout just to see if my process will work. If it does I will assemble a more permanent system. How did you get the orange stripes?
     
  3. Bob S

    Bob S Active Member Active Member

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    Doing multiple colors is fairly easy but time consuming.

    The first step is to anodize the part then dye it in the lightest color. Once that is done, dry the newly dyed piece (pat the part dry with a clean paper towel, do not rub as this can remove some of the color). I use two different methods for masking the color depending on the part. For the straight pieces I milled a 0.100 depth cavity. Here I used rubber cement diluted with Toluene to a consistency slightly thicker than water and using a syringe, put a quantity of glue in the pocket and tilted the piece until the cavity had a layer of cement. For the round piece I used precision vinyl tape of various widths wrapped around the part. You can get quite creative using a variety of these methods or vinyl masks to make symbols.

    The next step is to remove the unwanted dye by placing the part in straight bleach for a few seconds. This bleaches out the dye but doesn't remove all of it. Rinse well (VERY IMPORTANT to rinse well as bleach and sulfuric acid combines to create CHLORINE Gas, very bad for you!) and then put the part in 15% sulfuric acid (same concentration as the anodizing bath) for a few seconds. This opens the pores and removes the bleached dye making the part ready to accept the next color. Continue this step for each color going from lighter to darker colors.

    After the dying is complete proceed with sealing as normal. I usually remove the rubber cement/tape and then put the part back in the sealant for extra time just to be sure I get a good seal. A paint brush of Toluene can be used to remove any remaining glue.

    i hope this explanation helps you out! I had to do a lot of experimentation to get the right look and consistent results. Make sure you minimize the amount you handle the part and wear clean vinyl or latex gloves the entire time!

    Bob

    image.jpg image.jpg
     
  4. JT.

    JT. Active User Active Member

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    great expication on the diff color work
     
  5. eac67gt

    eac67gt United States Moderator Staff Member Moderator

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    I have anodized hundreds of parts and still have not tried multiple colors. It actually scares me to try it because of trashing a part and having to start over. Your explanation is great and your results look fantastic. This is definitely something I will have to finally dive into because it will open up another opportunity to sell more parts.

    Thanks!

    Have a great day!

    Ed
     
  6. Bob S

    Bob S Active Member Active Member

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    Good luck, multiple colors opens up lots of possibilities. If you want some inspiration, Google for 'anodized yo yo'. There are some really amazing results using these same processes and some imagination. Let me know if you need any advise!
     
  7. eac67gt

    eac67gt United States Moderator Staff Member Moderator

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    Thanks Bob!
    I have never been very artistic. I have ideas but have always been afraid to try things. My single color anodizing has always turned out great but it would be nice too expand on it. I know it would generate more interest and increase sales. I might have to take you up on the advise when I take that first step in multicolored.

    Have a great day!

    Ed

    Sent from my DROID RAZR HD using Tapatalk 4
     

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