Question on electrolysis setup

[Brad Ridgway]

So i've bought a bunch of old planes (and will probably buy some more)... Been reading several faqs on plane restoration / electrolysis. Forgive my electrical ignorance but:

What determines how many amps the circuit will pull and is that current constant or does it drop off?



Despite the amps recommendations i see in these sites, if i hook a battery into the circuit, the current draw is/can be independent of the charger right, so when people say get a 10amp charger in these posts and also recommend hooking a battery in parallel, it seems to me that the charger rating is irrelevant if i were hooking up to a deep cycle setup with enough capacity in amp hours to sustain whatever the circuit draws (i.e. if it draws 5 amps and i have 225Ah @25hr, i don't drain below 50% i could run it for 20 hours without recharging no? or am i missing something?

FYI: I have a Progressive Dynamics charger in my RV (40amps) with a couple of Trojan T105 deep cycles (in series) which i think would be great for this if it weren't parked at my in laws, but it is. The PD runs 24x7 and has been to maintain a float charge for years and i've never had a problem with it. I look at the Vector and Schumacher units and just feel like i'm not getting the same quality (and some amazon reviews seem to confirm).



thx in advance
-brad

[Matt Edwards]

Just my opinion here, but I wouldn't hook up an expensive battery or charger to an electrolysis bath. I'd stick with an inexpensive 10a charger and car battery (old). The battery isnt necessary as the charger by itself will work also.
That being said, I prefer either a citrus acid bath, or Evaporust.

JMO
Matt

[David Beeler]

A battery charger by itself works fine along with Arm and Hammer Washing Powders mixed in the water. I clamped 4 steel stakes that I got at Lowes around a 5 gallon paint bucket with a piece of wire running from stake to stake. I then suspended the plane parts in the center of the bucket. Connected the battery charger to one of the stakes and the wire used to suspend the plane parts. Worked great in a very short amount of time. Make sure you have the polarity correct or you will draw rust to the plane parts from the stakes.

[George Sanders]

Here is a site that explains how to do it very clearly. Antique-engines.com/electrol.asp I have used a 5 gallon bucket and laundry soda for about 3 years now. Results have been very good for me. Most of my tools, when found are true RUST HUNT finds.

[Tom Veatch]

...What determines how many amps the circuit will pull and is that current constant or does it drop off?...

Ohm's Law: Voltage = Current * Resistance.

If you apply 12 volts across the electrolysis bath, the amps drawn is entirely dependent on the resistance between the electrodes. A 10 amp charger or 100 amp charger will each produce the same amperage as long as they both apply the same voltage across the bath. Increase the voltage and the amperage increases. Using a DC welder as a voltage source can allow you to vary the amperage within limits since they are typically constant current devices that vary the voltage to maintain a selected amperage.

Using a battery and a charger in parallel with the bath will give you the same amperage that you would get with the charger alone. Connecting charger and battery in series with the bath so that you get 24 volts across the bath would double the amperage.

[Jack Ellis]

I know this isn't going to answer your question but if it's surface rust you're trying to get rid of, I would not use electrolysis. Too messy, too complicated, and at least where I live, problems with hazmat disposal.

I have a number of hand planes in various conditions and various states of rehab. To get the rust off, I took them apart and soaked the metal parts in household vinegar for up to 24 hours, periodically using a soft brass brush to loosen the rust. I filter the sludge and pour it down the drain, then replenish the soaking solution with more vinegar as necessary.

This is simple and cheap. If the plane ends up being too badly pitted, it gets pitched. Perhaps the only "drawback" is that my planes, all of which are users, have dull oxide finishes rather than shiny iron finishes. I think, though, that they're going to be better protected that way and I'm not putting them on display.

[Mike OMelia]

Too messy, too complicated, and at least where I live, problems with hazmat disposal.

I filter the sludge and pour it down the drain, then replenish the soaking solution with more vinegar as necessary.


Seems a bit contradictory, does it not? Any time you pour solutions with heavy metals in them down the drain, you are probaly breaking a rule somewhere (they are there even after you filter the sludge out).

However, rust is not the issue, its the metal components in the steel.

Mike

[Wilbur Pan]

I've found that for electrolysis, the lowest tech battery charger you can get works best. The fancier ones often have some sort of circuit protection that can trip in the middle of an electrolysis run, bringing your rust removal efforts to a halt.

I found that the cheapest 10 amp/2 amp battery charger that Sears offers works great for this purpose. It doesn't have overload protection. I use it on the 2 amp setting.

[Jack Ellis]

Seems a bit contradictory, does it not? Any time you pour solutions with heavy metals in them down the drain, you are probaly breaking a rule somewhere (they are there even after you filter the sludge out).

However, rust is not the issue, its the metal components in the steel.

If the planes were steel, I'd think twice. If they really are steel, I'll dispose of the waste differntly. However if they're cast iron, there's already plenty of oxidized iron going down the sewer from water mains and the like. I'm assuming all of my planes (Millers, Stanely, Sargent) are cast iron.

[Ed Hazel]

Why not just sandblast the parts?

[Lee Schierer]

Why not just sandblast the parts?

It leaves a rough finish and removes the paint. Electroysis is far more gentle and requires less specialized equipment than sandblasting.

[Charlie Doret]

Ohm's Law: Voltage = Current * Resistance.

If you apply 12 volts across the electrolysis bath, the amps drawn is entirely dependent on the resistance between the electrodes. A 10 amp charger or 100 amp charger will each produce the same amperage as long as they both apply the same voltage across the bath. Increase the voltage and the amperage increases. Using a DC welder as a voltage source can allow you to vary the amperage within limits since they are typically constant current devices that vary the voltage to maintain a selected amperage.

Using a battery and a charger in parallel with the bath will give you the same amperage that you would get with the charger alone. Connecting charger and battery in series with the bath so that you get 24 volts across the bath would double the amperage.

Not necessarily. Real voltage sources (as opposed to idealized ones) have what's called an "internal resistance" that you also have to worry about. Think of it as a little resistor in series with whatever you're driving - in your case the electrolysis bath. So, if your bath is very low resistance, the current will be limited by the internal resistance. For typical alkaline batteries (AA, for example) it's usually around 0.25 Ohm, so they won't source more than a handful of amps even if you short the terminals together. For a car battery it's more like 3 mOhm, which means that you should have no problem getting 100+ amps out if your bath has enough electrolyte in it, though the battery will be dead pretty quickly if you do.

So, if you really want to get the reaction going, dump a bunch of salts into the bath and use a charger w/ a high current rating. Whether doing so has other repercussions for cleaning your plane, however, I don't know.

[Tom Veatch]

Not necessarily. Real voltage sources (as opposed to idealized ones) have what's called an "internal resistance" that you also have to worry about. ....


Of course you're right, but that resistance is usually small relative to the load and is typically neglected in the "back-of-the-envelope" type of engineering we're doing here.

With a 12v source (actually battery chargers put out a little more that 12v) and sodium carbonate (washing soda) as the electrolyte, I'll get around 2 to 4 amps showing on the meter - both on the small "trickle" charger and on my larger "fast" charger. If I really want to roil the water, I'll use my 235 amp welder on a low amperage DC setting and put about 70 volts across the electrodes. Since there's no direct amperage meter readout on the welder, I figure I'm putting about 12 amps through the bath. Heats the water up pretty good.

[David Keller NC]

"What determines how many amps the circuit will pull and is that current constant or does it drop off?"

Brad - To answer your question, the total current through the bath is determined by: 1) The composition of the electrodes (in this case, of course, that's fixed), and to some extent, the concentration of the electrolyte. 2) The surface area of the electrodes.

Ohm's law does apply here, of course - Voltage = Amperage * Resistance. The voltage is fixed (by what you hook up to it - typically for a battery charger it's 14 volts), and the resistance is determined by the afore-mentioned electrode composition and the area of the electrodes. A much larger electrode area will result in a greater amperage pull, all other things being equal.

This doesn't actually let you calculate the amperage, but it does give you the info that using a significantly bigger anode/cathode will likely result in a siginificantly greater amperage pull.