Yep, so when resistance is low (before the oxide film builds) there's high current (volts = amps × ohms), once the oxide forms resistance high, current low - constant voltage, has to work that way.
Only other possible is a "foldback limiting" PSU which sees a low resistance - high current condition as a fault and collapses the voltage to keep the current under a limit, like my Thurlby, drops to a fraction of a volt into a short.
Dave H. (the other one)
I didnt know what I was doing. The dyeing I ran about 60-70c, almost made a mistake of having hotter. I ran out of condensed water from dehumidifyier so the sealing was tap water. From memory I thought sealing should be half hour, so it had that, then I checked temperature was not quite 90c on maximum. Looked it up that the minimum is 93c, so took it indoors to the proper hob for another half hour. Tbere wasnt really any staining, they looked good wet and slightly dull dried with tissue, but wd40 has restored the shine.How long did you seal it for? I seal in tap water at a slow boil for 20 minutes - if I leave it longer, I seem to get more staining. I rinse the parts under cold water after sealing and any 'bloom' seems to wipe off easily with a cloth. It's harder once it has dried.
I'd also like to do larger pieces, but like you, I'm struggling to find suitable containers.I want to do some sheet peices so I need a longer container to fit 600x300mm, any ideas? Id prefer the parts suspended vertically than laying flat, rules out the large polypropylene storage tubs.
Got a packet of dylon orange dye.
If anyone has small parts to be done I could use some test peices.
That looks like it would only take the sheet you mentioned lying flat. I think you'd be best holding the sheet on edge ('landscape' or 'portrait') so that the bubbles can rise freely.Im thinking one of these.
I was reading through this and getting quite excited as I was fancying trying to anodise this.That looks like it would only take the sheet you mentioned lying flat. I think you'd be best holding the sheet on edge ('landscape' or 'portrait') so that the bubbles can rise freely.
A 600 x 300 sheet is going to need 40amps+
I would just be wanting it clear anodised, would it turn out ok you think?