Difference in "colour" of anodized parts

[anodizeme4ever]

We tried to anodize 4 parts(2 were 1 size & 2 were another) in the standard 5 gallon pail all at once. There was a total of .65 sq. ft. and we tried anodizing at 12 amps/sq.ft. The rectifier zeroed out after 32 minutes. When we took the parts out, the 2 outside parts were noticebly lighter than the 2 inside parts. Should we buy more lead to cover the entire circumference inside the tank? Do parts need to be identical in size if trying to anodize more than one part?

[rclint]

You may be getting a shadow effect. I ran into to small a tank and had to upgrade, the tank is the cheap part, so no worry on that, use your equipment you have now if you decide to upgrade the tank, I really like the coolers for this work.

When you say your rectifier zeroed out what do you mena by this ?

[anodizeme4ever]

The current dropped to zero, voltage remained at around 27.
Do you not think the platess are the issue?

[rclint]

Originally Posted by anodizeme4ever

The current dropped to zero, voltage remained at around 27.
Do you not think the platess are the issue?

It sounds like you have lost connection (which is common problems) the anodize layer builds up and reduces the onnection between the wire and the part, anodize layer (aluminum oxide) is a constant fight with the wire connection if the connection is not perfect

You were running in constant current mode right ?

Clint

[anodizeme4ever]

Yes, using 20 amp, 30 volt CC/CV Digital Rectifier. I had the wires wedged in the threaded holes. Could it be they reached PAR?

kevin

[rclint]

Originally Posted by anodizeme4ever

Yes, using 20 amp, 30 volt CC/CV Digital Rectifier. I had the wires wedged in the threaded holes. Could it be they reached PAR?

kevin

Nope, the current should have been whatever you set it at. make sure you had it in constant current mode (the rectifier) if so then you lost connection. A threaded connection works pretty good, and a spring type connection that the tips of the wire will engrave the piece to be anodized, that's what kind of force we are talking when having a good connection, even then it can fail. The sput welder is a sure thing, but threaded and spring tension also works.

Clint

[rclint]

I could confuse myself I think

On the threaded holes, take your wire and threade it into the hole, if it has a bottom keep going when the wire starts to twist from the force of threading and it will not thread any further then you should have a connection that will hold. You may be able to double the wire and get a tighter fit also

I use what they call service entry wire for hang wires an dthreading into some parts, it's pretty cheap i get it froma scrap yard, prob 10 pieces in the insulation, not sure on guage, but it's just the right size at just the right price

Clint

[anodizeme4ever]

How do you know it's in constant current mode? There's no switch for this. I cranked the coarse voltage knob and the fine adjust knob all the way over and then set the current knob to the desired current and also fine adjusted
Have you had any experience with this spud welder? What kind of weight will it hold? Do you use the same titanium wire?

[rclint]

Does it say CC below the current adjustments, and CV below the voltage adjustments ? Mine has a little light red that lights up when it's in CC mode or CV, 1 light below and between the adjustment knobs for curent, the exact same on the voltage side. To set mine in Constant current mode you turn the volatge adjustment kbos all the way up to max (course and fine adjustments) turn the Current adjustments all way to minimum (both knobs again) and turn on the power, the light will come on, when all connections are made (normaly before I turn power on) then I set the current to what I want and the rectifier will hold that current and the voltage will adjust to make this happen. I'm not sure what kind of rectifier you have ?

On the sput welder you make the connection with the wire (you get a smal roll with the welder) you can order more wire in different size, this will hold a good bit, but if anything much larger than a machine screw or such and I will use hanger wire, the hanger wire supports the weight while the wire connection from the sput welder will serve as a perfect eletrical connection

I'm not to up to date on Titanium wire, I have some on the way for spring clips, but I have never used it so I can't comment on it, I do know even tho the Titanium wire wil not anodize, the aluminum part will and still build the aluminum oxide layer that is a insulator and non conductive on the part being anodized.

edit note** You use aluminum wire with the sput welder, cheap, and throw in the aluminum scrap when finished

[anodizeme4ever]

That's exactly what I do with the rectifier - sounds like we have the same. So when it reaches PAR, do you see the voltage start to fluctuate?