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Analyze this(not a movie review).......

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  • #16
    Here's the picture that Sid sent me.


    • #17
      Agitation promotes an even coating, the lack of it shouldn't prevent any coating or by itself make the coating thin.

      Be careful about creating two variables in your experiments. Attack one variable at a time, you will make things harder to figure out if several things are allowed to change in the same experiment.

      Different alloys or even small differences in prep. can cause the raw anodize to have different shades, so does current density.

      Your description "scratches easily" is disquieting. although anodize doesn't achieve full hardness until it dries out completely, it shouldn't scratch easily. What do you mean by "easily". Coatings grown at way too low a current density (under 2A/sq.ft.) do this. Can you reproduce a good electrical connection? Unless you are using a real CC mode power source (the current is held constant, regardless of resistance and voltage) you will be at the mercy of any connection resistance. CC can compensate for this, up to its max voltage capability. This is called "voltage compliance". However; even with CC, the coating resistance (PAR) you calculate from current and voltage figures will be wrong if the connection resistance is high, or even worse, changing as you anodize. Anodizing beyond PAR may help this situation, but it doesn't fix the actual problem. Problems like this will return unexpectedly and will haunt you. Please take connections seriously.

      BTW, the same evil effects occur with the "old method" no one was aware of it because they weren't trying to measure anything. Bad results were blamed on the aluminum alloy type, chemical reactions, etc. You still hear that alloys like 7075 are hard to anodize, no they aren't.

      We've had some posts here lately describing the pains and expense pros endure to get good connections (racking) ever wonder why?


      • #18
        Fibergeek- You dont think the lower piece in that picture looks VERY dark?The piece above it is what it started out looking like. I think it may have been cast aluminum. I will run some stuff that i KNOW is 6061 and see if everything turns out good again