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  • Spots, what am I doing wrong?

    Hi everyone.

    New to the forum and anodizing.

    Been going well but started getting spots with the anodizing.



    This only happened when I switched to CC as before I was on CC/CV.
    The reason I switched off CV is that it never got the amps near the 720 rule amount.

    For my 52" part it is saying 15V, 2.22A at 120 mins for a 1mill thickness.
    With CC it does after 20-30 mins go down to 15V but the first 20-30 mins it is 20-30v.

    Is that what is causing these spots?

    Before switching to CC.


    5058 Aluminium





    Last edited by JOGARA; 04-13-2018, 11:14 AM.

  • #2
    Even your before picture has spots. You aren't getting them clean enough. What is your prep procedure?

    Comment


    • #3
      Originally posted by dabeechman View Post
      Even your before picture has spots. You aren't getting them clean enough. What is your prep procedure?
      Washing in sink using washing up liquid and a non-scratch pad.
      Not touching with my hands.

      Comment


      • #4
        It look like you used alu wire for the second picture and titanium for the first?
        Strange that the wire didn't changed color. It should change to purple.

        Comment


        • #5
          Originally posted by JOGARA View Post

          Washing in sink using washing up liquid and a non-scratch pad.
          Not touching with my hands.
          That is your problem. Get yourself dedicated degreaser and heat it to 180 degrees. Be sure it won't eat your aluminum. Even the Caswell degreaser will dull your finish, so do not leave it in there for too long. Do the rinse test when you have cleaned your parts. Water should sheet off your parts.

          Comment


          • #6
            There's a host of reasons why this happens, degreasing is not one of them. While it is good to have a proper cleaning regime as dabeechman mentions you must look in another direction to solve the problem.

            You mention having success with CV as opposed to CC but didn't feel the amperage was right. The thing with CV is provided you have the correct SG for your electrolyte (180 g/L) the parts will draw the necessary amount of amperage on their own, with that you must not run beyond 60 minutes. SG must be lower to run the LCD method as is the choice on this forum (I prefer not to and stick with the industry standard of 12 ASF). Running for 120 mins without knowing your electrolyte strength risks taking the parts into dissolution which can cause your problems. You don't mention anything about agitation nor tank temp! Both of which are vitally important to controlling pitting. Lastly you haven't mentions what alloy you are using.

            Some possible changes to try would be as follows.

            Start with plastic tanks to prevent galvanic interference,
            Degrease/desmut parts properly
            Control bath temps 68 - 72 deg max.
            Agitate the tank properly
            Use aluminum wire to hang your parts.
            Titrate your tank to confirm Sulphuric and dissolved aluminum levels

            Let us know if you have success.

            Comment


            • #7
              Originally posted by Wes View Post
              It look like you used alu wire for the second picture and titanium for the first?
              Strange that the wire didn't changed color. It should change to purple.
              Only titanium. That was brand new wire in the first one, takes a couple runs to go purple?


              Originally posted by dabeechman View Post

              That is your problem. Get yourself dedicated degreaser and heat it to 180 degrees. Be sure it won't eat your aluminum. Even the Caswell degreaser will dull your finish, so do not leave it in there for too long. Do the rinse test when you have cleaned your parts. Water should sheet off your parts.
              I have some Hyperclene 80 for my part cleaning.

              I forgot to put in my full setup. Will list it bellow.



              Originally posted by gardinhackle View Post
              There's a host of reasons why this happens, degreasing is not one of them. While it is good to have a proper cleaning regime as dabeechman mentions you must look in another direction to solve the problem.

              You mention having success with CV as opposed to CC but didn't feel the amperage was right. The thing with CV is provided you have the correct SG for your electrolyte (180 g/L) the parts will draw the necessary amount of amperage on their own, with that you must not run beyond 60 minutes. SG must be lower to run the LCD method as is the choice on this forum (I prefer not to and stick with the industry standard of 12 ASF). Running for 120 mins without knowing your electrolyte strength risks taking the parts into dissolution which can cause your problems. You don't mention anything about agitation nor tank temp! Both of which are vitally important to controlling pitting. Lastly you haven't mentions what alloy you are using.

              Some possible changes to try would be as follows.

              Start with plastic tanks to prevent galvanic interference,
              Degrease/desmut parts properly
              Control bath temps 68 - 72 deg max.
              Agitate the tank properly
              Use aluminum wire to hang your parts.
              Titrate your tank to confirm Sulphuric and dissolved aluminum levels

              Let us know if you have success.
              The calculator I used is http://ndhsubmersiblescience.com/ano/720rule.html
              Said to go 120 mins for my part.

              I see a lot of people doing 60 mins so just went with what the calculator said.




              My setup is as followed
              1. Clean part with washing up liquid to remove general **** off the part.
              2. Hyperclene 80 at 20c for 10 mins.
              3. Acid bath for 20 seconds.
              4. Desmut for 5 mins.
              5. Anodizing tank going off the 720 rule calculator http://ndhsubmersiblescience.com/ano/720rule.html
              6. Baking soda bath for a few seconds
              7. Dye for 15-20 mins at 60c
              8. Seal in Acuseal 30 for 10-20mins (forgot how much I leave them in)
              9. Hang dry

              Comment

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