Quote:
Originally Posted by dave7352
Hi there, newbie hear 
Been doing some research in to building my own anodizing set up, I would be very grateful if some of you could just clear a few things up for me.
* If I have a variable amp power supply does it matter how big or small the cathode is?
* Is it better to have the cathode surrounding all of the inner wall of my anodizing tank?
* What could I do to get the maximum surface are coverage for a small amp power supply?
* When dyeing the aluminium is it important to keep it at the desired temperature or could you heat it up to say 140 F and them put the aluminium in and let it slowly cool for 20-30 minuets?
* Some pictures I’ve looked at of home built setups have air lines running along the bottom of the there anodizing tank, is this for cooling? If not what is it for?
*the temperature in my garage (where my anodizing setup will be) is often bellow 50 F will I need to heat my anodizing tank to 65 F - 70 F or will the reaction do this by its self?
* Do you have to use a sealant on the last step or can you just boil the aluminium for 20 minutes, what are the pros and cons of just using water no sealant?  |
The cathode should be at least as big as your largest part, and bigger doesn't hurt. I have mine running down the small side, accross the bottom, and up the other side. Lead will last a long time, but 6061 al will work too.
Maximum surface coverage for a sml PS? Not sure what you mean there, but the size of the part dictates how much current is needed. There is nothing you can do to improve a sml PS.
You'll want the dyes to be at 140F... when you put the cold parts in the dye, the temp will drop emediately, so you'll need heat while doing it.
The airlines are for agitation. A micro layer of heated ano bath will affect the ano layer. The ano bath needs to be agitated to keep the heat disapated.
It's important that the ano bath be maintained at exact temperature. I like to keep mine between 68F-70F... never higher than 70F in my opinion.
Also, ano bath temp affects resistance (it will take more volts at a given amps in colder bath). You'll definately need to heat your ano bath to the correct temperature, but don't forget, when you apply current to your parts, they will tend to increase the bath temperature. If your ano bath temp rises too high (even the micro layer right at the parts surface), desolution will occure (desolution is when the ano layer is eaten away by the acid as fast or faster than it's being built). Air agitation helps cool the ano bath too, but the fumes given off are significant.
Sealer step is important... I use the high temp sealer (boiling) for 20 minutes. If the parts aren't sealed well, they'll pick up finger prints, dirt, etc., and also you'll loose the dye.
Some guys steam seal with good results.