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Anodizing Bench - starting my own...

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aeroHAWK:
I joined this forum about six months ago because I saw Tom's anodizing bench thread. I had planned on setting up my own anodizing line, and Tom did such a great job of explaining and showing how to do it, I joined the forum and began setting thing up. I've done some work in that regard, so I figured I had better post some progress.... :thumbup:

I'm using smaller tanks than Tom did. Mine are two gallon instead of five. Plus I'm using picnic coolers for the heated baths. The ones I found are Igloo 9 quart coolers.

I made a manifold for pumping air bubbles into the tank to keep it "stirred".

Since the acid bath warms while anodizing, I opted for a larger tank for the increased thermal mass (and therefore slower heating). It is in the four gallon range, but since it isn't insulated like the coolers, it doesn't take up a lot more room.

I haven't yet made a bench nor have I gotten all the parts together to have my anodizing line complete. However, I have clear anodized over 50 parts of various sizes, with good success. And of course, I learned A LOT in doing so.

The most important thing I learned is to use a Constant Current power supply. I started with an old manual automobile battery charger. Fortunately it died (although it didn't feel fortunate at the time). The failure had me scrambling to find an alternative since I had a job to finish and I was behind schedule.

The parts I anodize are not large so I don't need a huge power supply. I had a surplus Laptop charger/power supply lying around so I connected it to a Current Control module I got on eBay. This what the charger looks like:

I was able to finish the job, but more importantly, the Constant Current module made a huge difference! The Laptop charger is 19 volts and anodizing in my tanks needs 13 - 16 volts (this will vary with the size of the parts, temperature, pH, cathode, etc.), the Constant Current module is a "Buck" (or step down) converter. It has a digital display for both Amps and Volts, and looks like this:

The Laptop charger is only 65 watts, and I would like a little more "headroom" for the larger parts I may anodize, I am "upgrading" to a Desktop PC power supply. It is really old (from a 386) so it is still limited but 120 watts at 12 volts is still an upgrade....

Since it is 12 volts, the Constant Current module needs to be a "Boost" (or step up) converter.

The one I got on eBay doesn't have the Amps/Volts display so I also got a separate display from eBay.

I'm currently in the process of putting it all in an enclosure. The module uses small 10-turn trimmer pots to adjust the current and voltage, so I am planning on removing them and wiring in a standard panel mounted pot for easier use.

Oh, I almost forgot... here is a sample of the anodizing I have done:

Bluechip:
I see no pics ??? Just the dreaded black cross.

Dave

John Rudd:
 :mmr:nice pics....

Are you going to add some colour to your items?.....Blue perhaps?  :thumbup:

DMIOM:
hi Aero,

good to see your setup developing.

Couple of quick thoughts :

Glad to see you're going with constant current, that's the way to get reliable, repeatable small-scale results.

Your actual anodising tank - you've got your aerating pipes right in the corner - ideal situation to avoid shadows is as close as you can to 360 degree surrounding with the cathode - lead flashing sheet or similar. I would fit the lead lining first and then the pipes on top.  Bubbling on its own may not be enough - you may need pumped circulation as well...   Note your comments on larger liquid mass reducing probs with heat build - but remember you may need to inject some heat to start with as well.

Talking of heat, note you're using coolers - what temp will they safely stand? especially boiling sealant.

You may find it interesting to read this MadModder thread on anodising (p.s. that's spelt the way the rest of the world does so if you searched anodizing you may have missed that thread!   :thumbup: )

Dave

Arbalist:
Nice setup, your results look good.  :thumbup: The last anodising I had done was what they called "hard anodising" which is I think done the same way except the acid solution is kept very cold? The results were good anyway.

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