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  1. #11
    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
    project 1 , 2, Dust Shoe ...

  2. #12
    For an experiment could you just use a standard lead acid car battery 3 sq/f would take 3 hours at 12A
    ..Clive
    The more you know, The better you know, How little you know

  3. #13
    Quote Originally Posted by Clive S View Post
    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.
    Last edited by Boyan Silyavski; 1 Week Ago at 05:08 PM.
    project 1 , 2, Dust Shoe ...

  4. #14
    Quote Originally Posted by Boyan Silyavski View Post
    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.

  5. #15
    Quote Originally Posted by Zeeflyboy View Post
    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

    Quote Originally Posted by Zeeflyboy View Post
    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.
    project 1 , 2, Dust Shoe ...

  6. #16
    The current dropping off is doing a constant voltage technique though no? You seem to be describing constant voltage but with a limit on the current.

    My understanding is that the constant current technique tries to maintain whatever current you have set by raising the voltage. So one takes the sq ft of the part, multiply by 6 (if using 6asf) and then set that result in the power supply, which will then slowly raise the voltage as necessary to maintain that current. Using the 720 calculator you can then determine that at 6asf for example, the final voltage will be 15v and it will take 2hrs for a 1mil layer.

    Thanks for all the tips - I believe I should be using a polypropylene tank, my slight problem is that my larger parts are quite long. I found a suitable polypropylene container in home base, but to get enough length its a 60L tub, which is a lot of acid, heavy and a big thing to store when it's far wider than needed in reality. I could get away with something much thinner, but never seen anything suitable and not sure how I would go about building my own tank.

    Would a fish tank work? You can get those fairly long and thin, but not sure about the sealant they use and the acid.
    Last edited by Zeeflyboy; 1 Week Ago at 02:47 PM.

  7. #17
    If it is only for one long part you could use some heavy duty membrane (think dpc under concrete) and make a temp. trough with timber to support it (outside of course). Or dig a channel in the garden to support it
    ..Clive
    The more you know, The better you know, How little you know

  8. #18
    Long pipe cut along in half ? like the ones they use now for drainage or water, they are from some heavy duty PP or PE. Any construction site will have pieces thrown
    project 1 , 2, Dust Shoe ...

  9. #19
    Decided just to buy an 80L polypropylene crate.... Internal dimensions are about 600x400x400ish mm so will fit the longest parts I currently plan to use and means I can do batches of smaller parts to save time.

    It's wider than I needed, but I have designed a little PVC pipe cooling system which will eat up some of the volume... will just run cold water through it to keep the tub cool. Whether or not it's necessary really, probably not, but at least it takes a few litres of displacement out of the tank which is a few less litres of acid to deal with!

    Cheers for the assistance chaps

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