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Originally Posted by Fibergeek
I can see by your post that you did your homework, anodizing is like everything else in Life, you get out of it what you put into it.
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Thank you. Apparently not enough homework. I hope to get a lot out of this as it is already taking up more family time than I had intended.
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Originally Posted by Fibergeek
I've heard this "900 Amps/min./sq.ft."stuff before. I have verified that the "720 Rule" is quite accurate since I can measure anodize thickness. That means replace "900" with "720". The 720 Rule is based on real electrochemistry (it has a provable mathematical base) the 900 stuff is from some amateur's website and has no basis at all beyond his particular setup. If your setup isn't identical to his (fat chance) it isn't likely to work. His connection method is poor, and he doesn't use CC, the 900 stuff is a fudge factor to compensate for this.
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You are correct that this is off a website... an old one now. after checking again it's been updated to the 720 rule now.
So using 720 my time should have been 46 min. Then I agree with the dissolution argument. On the previous attempt I tried .36 sq ft for 40 min. but the dye didn't take to well got nice even grey color, but I wanted black so I didn't bother sealing it. 52 min is the calculated time but I've read that 1/2 to 1/3 of the time is enough if color is the only concern and not thinkness or hardness... is this not the case also? Based on the dissolution problem of the previous piece I suspect my electrolyte temp wasn't high enough. My thermometer is only graduated down to 75. But it read just below there the whole time. It must be much more inaccurate past the graduation markings.
And on that same run my CD would have been 13.9... correct? Both 15.6 and 13.9 should be acceptable since I'm not using the LCD electrolyte. I want to keep my times down as time is money so I didn't want to use the LCD setup. Is there any way to verify what your solution ratio is? and what the effective high and low CD limits are? I have a borrowed 0-40A 0-40V power supply. I don't intend to do this yet but in an effort to shorten anodizing times I could increase current density... correct? to what extent? And I would need to increase my acid to water ratio... correct? What happens when you run higher current densities but not higher solution ratio's? What risks or disadvantages are there to doing this?
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Originally Posted by Fibergeek
You are correct in saying that you actually anodized at 15.6 A/sq.ft.. If you were using LCD electrolyte, the pores would have been smaller, not larger, not so small to make dyeing too difficult, just harder than it should be. This leaves excessive dissolution, and its characteristic of opening up the pores to too large a size. The 110 deg. dyeing is an error in the documentation, Caswell is been slow in correcting errors, but I expect that to change.
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So my next attempt will involve getting a thermometer that will read below 75 for the electrolyte, use the 720 rule instead, get my dye temp to around 140, and use 12 ASF for current density (maybe?)
I'm still unsure of what current density I should be operating at. I know it should be whatever works... but how do I get close in the first place?
Is there anyway to check what ratio of the electrolyte is? I mixed it up a while ago and forgot what it exacly was... either 1:1 or 1:2, but I can't remember. I'm sure this info would help me determine a suitable current density to run at.
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Originally Posted by Fibergeek
On what basis do you rule out #5? Threading is no guarantee of a good connection, its mechanical and is prone to failure just like any other mechanical method. We could verify connection quality if you provide some voltage measurements during anodizing.
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Sorry I can't quote voltages as I wasn't watching closely, If I had to guess it would have been around the 15V +-. What does this mean for connections? Is this where the 2.5 ohms comes in? But that only applies to the LCD setup... correct? What would I be looking for with a more dense solution?
My head's full for today. Whoever said anodizing is easy and forgiving was a little off. Maybe once a person gets all this sorted out it is but getting there is a rocky road.