recommended bath concentration for 12A/ft^2 current density

[NeoMoses]

I want to try out some 12A/ft^2 anodizing, mainly because it will be faster, and was wondering what electrolyte concentration to use to obtain a pore size favorable for dyeing. Thanks!

[potsked]

hey, what caswell used before for the HCD anodizing was 1:1 of battery acid and distilled water. this worked out to be more specifically 25% sulfuric acid. the high current is what im using right now.

have you had any luck with figuring out your problem?

i found my problem was using dyes at room temp (which works fine for me) but out in the garage room temp this time of year can be too low.

[neilfj]

Battery acid in a 1:1 mix with Distilled water is actually 17.5% by weight (or 9.5 by volume), not 25%.

If you're dyeing at under 110 degrees, you are extremely lucky that it is being absorbed at all. Room temperature is not the temperature of any room you happen to be in. Typically it is a range of 65-75, but I wasn't aware that any of Caswell dyes were recommend for use at room temp. In any case, I'm glad you got your problem resolved.

[potsked]

i know im going off topic here, and i apologize to neomoses for hi-jacking his thread

ive read from published sources that cold dyeing (room temp 65 - 75) produces very good results that are superior in color depth and brilliance to 'zapping' the part with hot dyeing. i would otherwise agree with caswell were it not for my own fine experience with room temp dyeing. that and buying 14 heaters is not an especially appealing notion. you should try it at room temp once or twice, see how you like it.

[NeoMoses]

No problems, potsked. Your answer to my question was exactly what I was expecting.

I'll also agree with potsked on the room temp dyeing. It works quite well, although it might be a bit slower than dyeing with warm dye. However, seeing as how LCD takes about 90 minutes to anodize, another 15 minutes to dye doesn't bother me.

[NeoMoses]

Thanks guys, the 1:1 acid:water mix is working quite well with constant current anodizing at 12 A/ft^2. I've only done a couple of batches, but it's looking like this will only take about 45 minutes per batch, a definate time saver.

[mcaswell]

Why would you want to do this when we have a MUCH better system. OK it's slower, but SO MUCH MORE RELIABLE

PLEASE change over to the LCD system. We aren't giving tech support on the old method.

http://www.caswellplating.com/kits/lcd_ano.pdf

[NeoMoses]

Why would you want to do this when we have a MUCH better system. OK it's slower, but SO MUCH MORE RELIABLE

Being a mechanical engineer, I'm an incessant tinkerer at heart. I have 2 tanks, one LCD and one 'test' tank. Don't get me wrong, I'm a huge advocate of the LCD system; it is very reliable and inexpensive.

My goal with all of this is 100% understanding/mastery of the anodizing process.

[potsked]

did you ever figure out that resistance problem? im using ye olde High Current Density method for now, until you figure it out (yeah im lazy, real lazy)

i read a post a little bit ago that referred to very similar voltages and currents that you and i were experiencing.

hope you figure it out, good luck

[NeoMoses]

Originally Posted by potsked

did you ever figure out that resistance problem? im using ye olde High Current Density method for now, until you figure it out (yeah im lazy, real lazy)

i read a post a little bit ago that referred to very similar voltages and currents that you and i were experiencing.

hope you figure it out, good luck

I think my problems were with my black dye, which had been left out, exposed to the air for a couple of weeks. I don't see the same problems with other dyes or the new black that I mixed up.