First off, I have been doing Ti anodizing for years on knives and I am very familiar with that process.

I have some parts I am making that will require anodizing because they will need to be specific colors in order to differentiate them from one another. I started learning the aluminum process about three weeks ago by watching people on youtube do it with simple supplies and methods. I did a few tests of my own and realized the need for a good system. I contacted Caswell and bought the smallest anodizing kit they offer. There were a few things it did not include, but I got those things too.

I am using a 3 amp constant current power supply (bought from Caswell).

I have had everything running for 3 days and made multiple attempts, but my parts will not take dye when finished. So, I am guessing something isn't correct in the anodize.

The parts are about 5.85 sq. in. for surface area, so I simply rounded it to 6.

According to the 720 rule calculator, with a current density of 6, I should have my amps set to .25 and run 120 minutes.

So when I set the power supply, I turn my voltage knob all the way up, and amps all the way down. I hook everything up and turned my amps knob to about .25 and wait for 120 minutes.

It should be noted that all of the baths are brand new, just mixed this past weekend. I am doing SP degreaser (190-200°F), deoxidizer / desmut (100°F), and then anodize (75°F). All baths are mixed correctly as per instructions from Caswell. The parts are rinsed thoroughly between baths with distilled water, and then neutralized after coming out of anodize before going into dye. Dye is heated to 135°F.

So after my parts come out of dye, they look the same as they did when they went in. I did have a few that tunred slightly pink (using red dye), but no significant absorbtion. No dye taking at all, which leads me to believe no anodize film is growing, or at least not enough. I am using titanium wire, and I had a good connection as far as the leads coming off of the power supply, because the titanium wire anodized and turned purple. I have also checked resistance between the parts and the hanging wire and found zero ohms (a good connection). I have used both very small gauge aluminum wire and also Ti wire for hanging wire.

I have also checked amperage throughout all of this to be sure I actually had the amp reading that the power supply was telling me, and it is correct.

I thought I had a pretty good mechanical bond to my parts, but I am questioning that now. At first I was using a spring type connection in a hole with the hanging wire. Observations were that the part would start off at the required .3 amps, and the upper limit of voltage, around 15 volts. I noticed that the amperage would drop off to almost nothing at around 15 minutes into the anodize session.

So then I took a brass bolt and nut and sandwiched the hanging wire to the part. (I know brass should not be used but I could not find Titanium or aluminum fasteners locally.) This setup produced a solid .3 amps throughout the entire 2 hour anodize, and the voltage went from about 1.5 volts up to around 8.This, to me, tells me that my initial springing wire hanging techniques were probably not sufficient. But even after this, the parts still will not take dye.

The only thing I can think here is that the part is not growing a sufficient enough anodize layer, and there is nothing for the dye to soak into.

Please, any help would be appreciated. I am scratching my head here.

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