Electrolysis Tank

[JimT]

I have tried an experiment with my tank. I switched from TSP to washing soda, Arm & Hammer. I exchanged two rebars and put two pieces of bed rail angle iron in their place and added a piece of bed rail angle iron. Prior to doing this the tank would start out with cleaned up rebar, TSP, and the charger would show about 4 amps. After about 4-5 hours the amps would start dropping off sharply until they hit about 1/2 amp. Then it would be time to clean the rebar up again.

This time I added the angle iron, more surface area, and two rebars, the amps started out at 6 amps (I have a 6 amp charger) and held for several hours. After about 8 hours the charger was still showing 6 amps. Now about 24 hours later the amps were down to 2.5 amps. Time to clean the electrodes, but the fender in the tank should be ready to come out now.

I think it is doing a better job with the angle iron. I guess because there is more surface area on the angle iron than on the rebar (takes longer to rust up). I can't say if changing from TSP to washing soda changed anything as I change to angle iron at the same time I changed to washing soda. But the combination seems to be doing a better job at holding the amps and there is less time spent in the tank cleaning the parts.

Thought I would throw this bit of information out there for food for thought.



JimT

[ScottyD'sdad]

I have been using 1.8 x 4 inch atock for electrodes for2 years. T use 4 of them. I justhelped ConnectiKit with a tanklast week.He has some 1/4 x 4 inch stock for electrodes.we weld a small stub of rebar for attaching purposes. Ed

[JimT]

Since the bed rails are painted I just grind the paint off the tops of the angle iron to attach the clamps to it. I also grind off the paint on the portion of the angle iron that is in the water. Welding a piece of rebar on the angle iron or what ever stock your using is a good idea. I can get bed rails at the local recycling station from time to time. They come in handy for all types of things.

JimT

[Rudi]

Jim:

We have been using the re-bar cause it is cheap (read FREE for me), and it is easy to cut. This was before I had my own welder. Now I think I am going to do what Cecil does.. and that is save up the old lawn mower blades and weld them to short pieces of re-bar. That way we multiply by a least 10x the area of the anode. This certainly increases the effectiveness of the tank.

[bob in CT]

With increased concentration of the electrolyle, I pull 12 to a all-time-high of 20 amps at 6 volts. I am finding that the parts are ready to come out after a few hours even with the amperage falling off fairly quickly (only 1 lawnmower blade and 4 rebar).

Bob

[Cecil]

In previous post I explained that I have now gone to double mower blades on each of the 4 rebars in my tank. I can have the paint off a fender in one large sheet in a little over 24 hours. I know that the more amperage the better but I still believe the secret is in the surface area of the anodes. But then again who cares as long as it works. and to think the first Cub I did I wire brushed everything. It took forever.

[JimT]

Rudi,

I get the bed rails for free too. I agree with you, the more surface area the better the tank works. I had paint coming off the fender in 8 hours. Thats the best the tank has worked. I left my first rear wheel in the tank with rebar and it took about 3 days to clean up while cleaning the rebar. The second rear wheel I used the angle iron and the same results in 24 hours. Think I'll stick with the wider anodes.

JimT

[Jim Becker]

There is one more point about rebar that I have attempted to make in the past. Much of it is produced from leftovers and bad batches of steel. So you never know what you are working with. I am sure that some batches will rust up and quit working quicker than others. Results from one time to another can vary.

[48 BARNEY CUB]

HEY THAT LOOKS LIKE A GOOD SET UP

48 BARNEY CUB

[Buzzard Wing]

Yep more surface area is better.

And Jim is very right about the rebar.... there is a huge variation if how well they work, some are just worthless. So when I get them I only get 4 at a time, usually when I am too lazy to run the others through the wire wheel.

Guess I better start looking for some mower blades if I want to do that real rusty fast hitch this winter.

[bob in CT]

I know some may want me to go away on this topic, but I have to comment on a couple of things here. I spent 20 years in the field of metallurgy including time on melt decks in everything from Big Steel to Mini-Mills and more time in the labs where the equipment I sold measured the steel chemistry. For the last 10 years I have been in electrochemistry. I'm not an expert in either, but I've picked up enough to hold my own.

First, rebar mills take their steel-making seriously. There is a lot of money invested in a heat of steel befor it is poured and the chemistry is right before the ladle is tipped. Rebar has to meet standards and specifications and while they are not as tough as tool steels or exotic alloys they have to be met. There are plenty of lawyers around just waiting for something to fail if they don't. But the quality of rebar is not at issue here anyway, because we are dealing with electrochemisty, not metallurgy.

When you have a rusty part connected to negative, some of the iron oxide is reduced to pure iron. The reason you have a conductive electrolyte is so the ions can move to and from the anode and the cathode ( + and -) .

Now, back to the part. The bubbles coming off your part are hydrogen gas bubbles. So what happens to the oxygen that was pulled out of the iron? This is conducted in ionic form to the rebar/lawnmower blades where some of it come off as oxygen bubbles and the rest of it reacts with the iron to make rust. The rebar that is cleanest, and closest, reacts first as electricity wants to take the easiest path (which is why I made my path easier by increasing the electrolyte) . Have a big surface area means you can pull more amperage for a longer time. Amperage will fall off when the rust is converted or when the anodes are so crudded up it is hard to "find" the iron to react with. Since the iron is consumed, this is called a sacrificial anode.

Other anode material could be used. Stainless will work, but the nickel is bad news as a residue to dump and so is chromium. Hexavalent chromium mentioned before is really hard to make and highly unlikely. Other alloy materials like vanadium can be very dangerous, so rebar is safe as it is not an alloy except for trace metals that come from scrap metal but this is controlled very well as we have the best scrap in the world.

Material like graphite would be great. No rust, no cleaning and instead of rust you would get more oxygen bubbles and maybe some CO2. Titanium and noble metals like zirconium would be great too, but these are worth so much in scrap, they would buy a lot of rebar and wire brushes. Plus all that rust is showing you just how much work you have done.

So these tanks could be like a car. You have your basic grocery-getter and then there is NASCAR. It would be easy to build a NASCAR tank with unlimited funds, but the trick would be to get someone else to pay for it and get 100,000 people to pay to watch it too

But one you understand what is really happening it is easy to see that big anodes are the way to go along with an efficient electrolyte. BUT. If somebody gives you some free titanium, grab it

[Joey]

Wow. First it was Eugene with automotive science and now it's Bob with metallurgy and electrolysis. You guys really know your stuff. Excuse me if I ask what may seem like goofy questions now and then because these areas are not my strong points. I still haven't had time to set up an electrolysis tank but I think I'll still have to read and read again all the posts to beef up on the setup and workings of a tank. It's nice to know there are guys out there that can help when it's needed!

[Buzzard Wing]

Thanks for the education Bob.

I recommend 'the tank' for many parts, like wheels. It is best for things that are hard to reach with a wire wheel and in some ways it's better than sandblasting (I need to pay for that). Guess I need to make a trip to the scrap pile and see what I can find.

http://s2.photobucket.com/albums/y40/Bu ... 18c171.jpg

http://s2.photobucket.com/albums/y40/Bu ... 5567e3.jpg

[bald]

Rudi! Thank you. While cleaning up in the workshop this morning the dozen old mower blades hanging on the wall caught my attention. Figured they would need to be thrown out. Now, they'll go for ET electrodes. If I paid you for all the things learned from you...you'd be quite a bit richer.
Thanks, bald