Posts Tagged ‘Astron’

I figured it was about time to set up my anodizing line so that it would be more useable. I had played with anodizing awhile back and really struggled. I was able to succeed at it however it was a result of more luck then chemistry. Anyway…I decided it was time to revisit the project and hammer some knowledge into my head. I am pleased to say that with the anodizing process I have gained a solid understanding of the chemistry, and factors involved, and therefore have been able to reproduce consistent results using proper set up and calculations.

The type of anodizing I have been doing is considered LCD (low current density) CC (constant current) Type II anodizing. I want to be able to anodize some of my machining projects and since the size of my lathe determines the size of project I don’t need a huge tank to perform the process. Right know I have set myself up a 4 gallon bucket which is plenty of room to perform the current (pun intended) tasks.

For those of you who are new to home anodizing the process is probably unknown. For myself I separate the process into 2 sections. First one is the process of anodizing, the second is the process of dyeing which is what gives the aluminum its color. For now I have directed my attention to the anodizing portion.

I have been practicing my aluminum TIG welding on scrap metal and decided it was time to put my practice to use. Using some 6061 aluminum flat bar and round bar I welded up a hoop to sit on top of my 4 gallon bucket. The hoop allows me suspend my parts into the anodizing solution as well as holds my agitation lines. I welded up a bracket in order to clip a 150 watt aquarium heater onto the side of the tank. Then I built some 6061 aluminum cathodes to aid with the “negative” side of things.

I was able to track down a used power supply which was in great shape. The unit I am using is an Astron VS-50M which is a 50 amp 15 volt variable DC power supply. It has plenty of jam to perform the smaller projects I am anodizing.

Sample dye colors on aluminum knobs

With the tank set up coupled with the massive amounts of research I had done I started turning out great consistent, well controlled results. Since I run small parts through the system I rely on a DVOM to monitor my current draw which allows me to dial in the power supply.

Once the part is anodized it can then be dyed to any color. I have 6 dyes, some of which I have sampled and some that still are waiting discovery. The process of dyeing is nothing more then soaking the part in the dye tank, at the right temperature, for anywhere between 1 to 15 minutes depending on the shade of color desired. Once dyed the aluminum can then be sealed. I have experienced some blotches with some colors which I believe is a result of poor cleaning of the part. The cleaning process is incredibly important to the success of the entire operation. I have a cleaning sequence I perform however it needs some tweaking.

Overall I am pleased with my results. The setup is compact and performs its function. Overtime I hope to build up a sample library of anodized finished, colors, and dye techniques to be able to reference to.