Power Supply for Electrolysis

[Reddinr]

If you do want to measure current and have a volt meter but not an ammeter, you can put a resistor in series with one lead and measure the voltage across it.

A 1 Ohm resistor at 3 amps would measure 3 Volts for example (And warm up pretty good due to the 9 Watts.)
A 0.1 Ohm resistor at 3 amps would measure 0.3V and only need to dissipate 0.9 Watts.,
Etc.

A resistor maybe rated double the power you need is a good plan.

Current = Voltage / Resistance.
Power = Voltage^2 / Resistance or Current^2 * Resistance

 

[Rick_B]

I've used a lot of evaproust but at $30 a gallon it would be pretty expensive to clean up a 6" diameter x 30" steel tube. Maybe laying it down in a trough and doing a little bit at a time?

Rick

 

[markba633csi]

You don't really need a meter- the bubbles tell you that it's working
And 10-12 amps would be more than enough current

 

[Eddyde]

I've put larger parts in a trash bag, put the bag in bucket or cooler, put the Evapo-Rust in the bag. Then filled the remaining space in the bucket/cooler (outside the bag), with water. (like brining a turkey) The water maximizes the contact of the Evapo to the parts, though you don't want to put too much water or it will push the bag tight to the surface of the parts You just have to find the balance. Also, be carful not to poke holes in the bag, I usually triple them. With a 6"x 3" tube you might still not have enough to cover it with 1 gallon but you may be able to fill the tube with smaller parts or som other type of ballast.

 

[pontiac428]

For an electrolysis/anodizing power supply, you get the most flexibility if you can select either constant current or constant voltage modes. The power you need is based on the flux density required. For constant current, it's single-digit amps per square foot. Voltage depends on the process, but there is a wide window. Caswell has good guidance for setups.

I would avoid switching power supplies for plating, but that's just me. Those who live deeper in the weeds can spec a switching power supply that is suitable, but not all of them are. A friend bought a cheap chinese switching bench supply from amazon and uses it for plating. My bench supply is an expensive German lab-grade unit that I will not ruin by dipping the leads in salt water, so I opt for the constant voltage of a transformer based automotive battery charger that I can set from 2-50 amps, and it will hold that until the anodes are saturated and need wire brushing.

Electrolytic derusting is not a messy process by any means. It's washing soda and water, no hazmat, easy rinse. Definitely gives the best looking results for my time.

 

[brino]

I've used a lot of evaproust but at $30 a gallon it would be pretty expensive to clean up a 6" diameter x 30" steel tube. Maybe laying it down in a trough and doing a little bit at a time?

I have always seen lines left at the evaporust/air boundary when trying to do things piecemeal.
Depends on what the end-use is whether this is acceptable.

This is one reason I like electrolysis over evaporust for big/awkward items.
I can fill a rain barrel with washing soda and water very cheaply!

Brian

 

[Shotgun]

But, @pontiac428 , the typical computer power supply is free, and all you have to do is ground the purple wire to make it work. Then you get 3.3, 5, 12, and 24 volts out of the same box. And from multiple leads so that if you screw one up, you have several others.

Did I mention it was free with the dumpster dive?

 

[pontiac428]

Free is perfect! I just wouldn't run out and buy a switching power supply for plating. PC supplies are plentiful and disposable. I approve of it in this case, there's nothing to lose and good insight to be gained.

If you were building it for a "customer", I'd get the *correct* power supply, but if you're still experimenting, then by all means! Put that PS on a power strip or other line protection with a 15a breaker, just in case the caps or the transistors don't like the salt bath load.

 

[Rick_B]

But, @pontiac428 , the typical computer power supply is free, and all you have to do is ground the purple wire to make it work. Then you get 3.3, 5, 12, and 24 volts out of the same box. And from multiple leads so that if you screw one up, you have several others.

Did I mention it was free with the dumpster dive?

That"s not exactly true - see here https://www.hobby-machinist.com/thr...y-for-electrolysis.105871/page-2#post-1036351. I spent well ovwer a week on 3 different forums trying to get a computer PSU to stay on. No luck
Rick

 

[Jake M]

I've used a lot of evaproust but at $30 a gallon it would be pretty expensive to clean up a 6" diameter x 30" steel tube. Maybe laying it down in a trough and doing a little bit at a time?

Rick

It'd still be expensive for a pipe in particular, but I've had more than one occasion where instead of a "container", it was cheaper to buy a "barely big enough" PVC pipe, and a cap, to make a "deep and skinny bucket". Never kept one long enough to know if it'd be an heirloom piece, but they work well for the amount I've ever used one. if you WANTED to use evaporust.... You could probably double cap a "displacer" piece of pipe on the inside to get rid of a bulk of the inside space within the workpiece that way. I know that's not what you're asking about, just throwing it out there.

On your electrolysis- Amps really aren't that relavent, WITHIN REASON. You can do a plenty good job with a two or three amp phone charger (you'll need to cut the USB end off of it.....) Another strong option is the old school, metal case, non safetyfied, "everybody used to have one" 10/2 amp, 6/12 volt battery chargers. The six volt, 2 amp setting is solid to just set and forget. If you go to a larger charger that doesn't have such a low setting, you'd have to measure it initially into clean water, but you can easily set that to "reasonable" simply by using the crudest guage (like built into most chargers) to control the electrolyte concentration. Amps and volts are gonna do their own thing and settle in where they want to be, but setting that up to just a couple of amps to begin with means it'll sit quiet and happy for you as it does it's thing.

I suspect you're going to find this is not going to be an overnight "set and forget" project with electrolysis. The inside and outside surface of the tube may well give you fits about preferential current paths, and need (or at least want, in terms of time to completion) some readjustment of the annodes as the project moves along.