Re: How much acid in bath?
[quote=cameraman]I've noticed that larger surface areas (300-400+ inē) produce curves with appreciable, steady voltage drops.
I never do pieces that large. I suppose that's why I've never seen the slope. Nice to know it exists I guess. I don' find it particularily useful though.
>>I'm not seeing that. Let's say I want to anodize 223 inē at 9.3 amps. I suppose the 223 * 5 = 1115 is easy enough, but who would want to divide 1115 by 9.3 in his/her head??
I'm not disputing the fact that the calculator is going to be easier. You picked a pretty screwey number (9.3). I'd just use ten amps amd be done with it. The math is easy then and on a piece that large the .7 isn't going to make much difference.
>>know that when the voltage is outside that range that it's indicating a problem:
Your right on that count. I use the voltage for that kind of thing too. But I don't watch it as an indication of when the anodizing is done, which was, as I understood it supposed to be the reason for the calculator generating the voltage reading.
>>You didn't address agitation in your posts.
So far because of the small pieces I've just been stirring the bath every few minutes. As a matter of fact, just to day I tripled the size of my tank (still small about 3gal) so I'll be installing a pump. I've had no real problems so far. I watch it closely. No drastic thing like you mention going on.
>>Your method causes parts of different size to be anodized at different current densities.
I'm going to assume you mean different size parts in the same bath. If this is what you mean then - No it doesn't. If you think about it a bit, if you have total current of say three amps going into the tank the current will divide itself up according to the resistance of the path to the each part, which is directly proportional to the parts size. Therefore the current to each part and therefore the amps/sqin is self regulating per part.
Please understand that this is within reason of course. I'm not saying that a bath with a piece 100 sqin and another piece 2 sqin won't have problems. But I've always put all the pieces of a project that I want the same colour into the same bath (small quantities) and thre is quite regularily a ratio of 20:1 in size difference and they all come out the same colour.
If you were speaking about doing separate runs of the same part then yes, you'd need (as always) to make sure the CD i(and everything else is the same for each run. That's a given for the reasons you mention.
>> You said "current your supply and connections can handle"
Sorry I've repeated these notes in a couple of threads. I also should have added "within the normal range of anodizing" which for me is betwen 4.5-12 A/sqft). I wasn't suggesting you supply current based only on the wire size to speed up the process.
>>If your method works for you, great, more power to you, but I'm not seeing any benefit to it .
My method isn't really any different. If you juggle calculator a bit you can get it to come up with the same numbers I get - albiet with a bit higher - but not unreasonable CD's.
Sage
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