Power supply for anodising?

[Clive S]

Anodizing needs Amps not Voltage

I don't think you can have one without the other

[Zeeflyboy]

0-15 volts is ok for up to about 6amps/square foot which is fine for the LCD method it seems, if going with 6asf that allows some fairly large pieces to be done with a 40 amp power supply.

30v would allow you to run at 12amps/sq foot, so you could get parts done more quickly but the power requirements quickly get out of hand for anything other than small to medium sized parts, but it is twice as fast.

I think 0-30v and 40 or so amps would be ideal, my largest part so far is about 2.6 sq/ft so at 12 asf would require 32 amps but I haven't seen any capable of that sort of power within a reasonable price range. The closest is that first link at 0-30v and 30 amps. I'm not doing it on a production basis so it's not a huge problem to run at 15v and 6 amps/sq ft and just accept that it'll take 2 hrs for a mil rather than 1 hour.

Jonathan - that looks interesting, I'll do some reading up and looking around at your link a bit more closer later thanks. The amps of the one you linked won't be sufficient to do the larger parts at 12 amps/sq foot but maybe I could just drop down to 6amps/sq foot for the larger pieces and it still leaves me the option to run at a higher voltage to do smaller pieces more quickly at 12 amps/sq ft.

Thanks for all the input guys!

[Boyan Silyavski]

40AMP 15vdc PSU will be good for ~7 square foot at 6Amp/Ft² density which is the recommended density for home scenario. Here is the calculator which i assume you know of, but anyway i will pass the link. I have tested it many times and it works perfectly.

For me price wise it was the perfect one PSU, having in mind i bought the acid in 20L

[Clive S]

For an experiment could you just use a standard lead acid car battery 3 sq/f would take 3 hours at 12A

[Boyan Silyavski]

For an experiment could you just use a standard lead acid car battery 3 sq/f would take 3 hours at 12A

I used that while waiting for my PSU. The thing is that there are certain times where you have to take certain steps and there is nothing better watching at the display what's happening with the Amp draw. In fact you have to limit it at the beginning, hence the need for Volt Amp separate control. I guess with and digital amp meter you could do that monitoring. With the proper PSU and using the calculator above, i was able to reach desired anodizing thickness at first try.

[Zeeflyboy]

I used that while waiting for my PSU. The thing is that there are certain times where you have to take certain steps and there is nothing better watching at the display what's happening with the Amp draw. In fact you have to limit it at the beginning, hence the need for Volt Amp separate control. I guess with and digital amp meter you could do that monitoring. With the proper PSU and using the calculator above, i was able to reach desired anodizing thickness at first try.

I'm certainly no expert, but from my reading it seems the key to consistent results (especially when dying the parts after) is to use constant current from a proper power supply.

Have you guys ever found a source for 6063 T6 aluminium for cathodes or do you just use lead and be done with it? I can't find 6063 T6 in any decent size.

[Boyan Silyavski]

I'm certainly no expert, but from my reading it seems the key to consistent results (especially when dying the parts after) is to use constant current from a proper power supply.

The constant current is to limit as i said to a certain current the current draw. Then current starts to drop at a certain time, when certain thickness is achieved, hence you can judge the thickness by the current draw. You can not give more current than it could take when there is the anodizing layer already formed

Have you guys ever found a source for 6063 T6 aluminium for cathodes or do you just use lead and be done with it? I can't find 6063 T6 in any decent size.

I don't know how big you are going to make your tank but here is some friendly advice:

1. Dont be cheap on the container and if possible buy proper anodizing container. make sure it's from the right plastic. And keep the rest in dark place inside.

I used a plastic one from chinese shop which i deemed good at the time and it worked well. In fact i bought 2 of them , transparent, and one was fit inside the other as extra security.

That did not stop the original 20l plastic container to brake in my hands half full with acid when i was moving house next year and 10l of acid to fall and splash from 1 meter around me. Luckily my reaction was fast and as i always use full face protector , working trousers and protective boots around acids and when welding, so i got without a scratch. The plastic have deteriorated which is very strange, but i think that was result from me leaving it outside, though it was covered. The chinese transparent boxes were ok though

2. Junkyard is your best place to go and find aluminum sheet. Any sheet will work. I used 1mm sheet with great results. If anodized, just use the other type of acid that you will use for cleaning your pieces to wash away the anodizing. Do the tank properly and use aeration, temp monitoring. If you do the tank big enough there will be no need for temp control, though if you are serious enough its not a big deal to DIY a way to cool the tank. No need to say that you must heat it using fish tank heater to the proper temperature.

3. If there is a way to do all that outside open air beneath a shelter or sth, that's the best way. It stinks and is dangerous for health. I wear respirator with proper filter / which is different from normal painting filter/ . Maybe you know summer here in Spain, every time i was anodizing i was dressed like a nuclear response team, sweating like a pig, but health is quite more important. My tank was about 70x50x50cm and i dont see how sb will do that inside if there is not an extractor on top of it. Anyway, is best to use an extractor even outside so fumes go somewhere else , hopefully not your neighbours bedroom window


4. Check all that works correctly with water before using actual acid in the tank. Do yourself a favor and buy a water osmosis sytem as you will need a lot of water, so buying distilled water will not do. Even for small projects.