Saturday, January 2, 2016

Anodizing Tips: Setup Parameters

I've been asked many times about the basic parameters for type 2 anodizing. below I will list the voltages, temperatures and basic information that I use for anodizing. This tip page does not include dyes, dyes and de-smut will be a later topic).
Green AEN
Term used: Dissolution = When the acid eats back the anodized coating faster than the end current can produce.

Jet Black Anodizing
    Voltage: I run at 14.2 to 14.8 volts. This can vary a bit depending on the acid strength and tank temperature. Warmer tank = lower voltage. If the voltage is too high the parts will start to burn. If the parts burn at 14.0 volts then the acid is too strong. If the acid is too strong than pitting (Severe burning) will occur.
    Amps: Amps will self regulate. Amps must fall during the process. Amps will fall fastest at first then slow down. The final value to dissolution will be about 70 - 75% of the starting amps after 5 minutes). In other words if the starting amps after 5 minutes is 2.0 then will be anodized fully at 1.4 to 1.5 amps.
    Time: I go 1 hour 10 minutes. I go less on silver. Going longer time will hit dissolution. Really it's only necessary to go as much time as needed to take full dye and no burning.
Hot Pink
    Temperature: 70 degrees. Some dye wont take with cooler tanks (Grey BL, Pink, Reds I've had issues with cooler tanks). Warmer tank = lower voltage.
    Agitation: I use a wave maker. I don't like the bubble method but some feel is ok.
    Acid: Sulfuric acid at a 10-15% ratio. There is a 720 rule or formula but I don't use it. Really complicated and how to find the surface area of a bolt? Change the bolt and new formula...hmmm. Most rookies start with way too strong acid bath. I use a hydrometer value of 1.4 baume.
    This step is the hardest to get. My advice is a 10% bath and follow the above values. If it's too weak add a bit of acid. Remember its much easier to add acid then the split the tank to reduce.
     New acid tanks can burn parts easier. Adding some aluminum matures the tank and helps resist burn. I add phosphoric and oxalic acid in very small amounts but isn't needed. This can help burn and black tracks. Clean Tanks are very important...I will follow up on this later.
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  1. if you anodize and it comes out a color you did not want, what is easiest way to get dye off of the aluminum. Thanks


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