need help please (novice)

[svryder]

Hello all!
Newbie to the board here . I work for a prototyping firm that makes models of consumer electronics. We've decided to break into anodizing with a caswell system. We purchased the setup over a year ago (pre lcd) I've recieved the new voltage parameters but my power setup is far from optimum, currently a 6A battery charger. The first power supply we got was a 60 amp voltage adjustable ,which lasted a month before I crossed wires and killed it. DOH! Next we got a 10A non-adjustable reg. power supply which just fried inexplicably. Now this unit provided decent results although I don't have a rheostat to control it. With this unit I was able to do a run of samples for my client in various shades of orange to reddish. Well he chose an orangish tone which I then tried applying to the actual parts. Now the parts come out a brite gold even when dipped into an obviously orange dye formula at 140F. My Tank is at room temperature. De-smut at 100F. what is preventing absorption of the red? I've tried different anodizing times with mixed results. I understand that control of the current is critical but what precisely do you change and why? thanks everybody

[NeoMoses]

We're going to need a little more information to solve your problem, so let's get started. I'm assuming that your acid bath is the old concentration, not the new LCD 1:3 concentration. If so, you should be anodizing in the 12-15 Amps/ft^2 (ASF) range. Constant current anodizing is still recommended over the old constant voltage; it will give you better batch to batch consistency.

Many things will affect the absorption of the dye: electrolyte concentration, current density, anodize time, dye time, dye color, etc...

In general, I've found that a lower current density will generally give you darker colors but a softer layer. Higher current densities generally give less vibrant colors but a harder layer.

What we really need to know is the voltage/current that the correct sample was run at. Was this a 12V power supply, 15V, or something else? Even though the power supply was rated at 10 amps, it will only put out that amperage when given a sufficient load.

Finally, what power supply are you using now? We need to know what you have control over so we can recommend ways to help.

If you have the opportunity, I would try to get the 60A power supply fixed or possibly look for a new CC/CV power supply to fit your needs. You can pick up nice 20A/30V CC/CV power supplies for around $300.
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[svryder]

the succesful run was using a 12v 10A power supply w/no current control. The anodize tank is 1:1 as per the old instructions. This is part of the trouble i'm sure. I've been given permission to purchase everything I need , I just don't want to buy the wrong stuff. Can you give me more specific information about the appropriate power sources? I am looking at a unit in MSC listed as high-stabilized constant current/voltage 0-30v/0-10A 400W w/ twin digital displays $336. Would this work? I looked at the units offered by caswell but it looked like only the 3A unit was CC/CV. Do you know of any related ebay units? The work I do usually involves small parts no more then a few square inches. The largest piece I've done was the upper bezel of a pc keyboard about 15" by 1.5".

[NeoMoses]

The PS from MSC sounds like it should work just fine, but like most things from McMaster and MSC, it usually costs a bit more than average.

Another power supply that should work very well for you is one like this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=32720&item=3807909166&rd=1

It has twice the current of the one from MSC and is about $250 shipped. It should allow you to do fairly large batches of parts (~1.67 sq. ft.), even using the old anodizing bath. I've found that a larger power supply is always welcome; I've pushed my 20 amp power supply to 17 amps so far... and I could still fit more in my tank.

[Sid03]

I purchased one of the PS's that Neo linked to, and off of the same person on ebay. Just incase your thinking about it.....PS has worked well so far, transaction with the seller was smooth, and PS was delivered well packaged.

[Fibergeek]

Since you are buying the power supply for your company and not yourself, it might be better to get it from MSC. Your company probably has an account with them, and if anything goes wrong, or you just don't like it, MSC will exchange it or take it back, no questions asked.

I agree that having more current and not needing it, is better than needing more current and not having it.

[svryder]

hey guys
thanks for the help. Neo, I ordered the mastech 0-30V/0-20A you linked to. Can't wait to get it up and running. Predictable results forthcoming...