Project #3 from Hooda- Electrolytic rust removal EXPERIMENT!

[hooda]

So, after reading DaveO's excellent thread on electrolytic rust removal, I posted there on the idea of applying the concept to a piece too big to fit in a tank. As luck would have it, yesterday morning I stumbled across a massive Boy Scout Garage Sale. I ended up leaving said garage sale with this:



For the princely sum of US $5.00, I am now the proud owner of a very old, very cool jointer/planer, circa 1950's. The make is "Homecraft" by Delta/Rockwell, and the condition is excellent. Looks like it was bought new a half a century ago, used a time or two, and sent to the corner of a garage where it sat until now. The bed and fence have a perfectly uniform layer of surface rust, absent any deep pitting or gouging, leaving me to believe that it's just rust due to exposure, not drops or anything more destructive. It looks to me to be the prefect candidate to try the concept of electrolytic rust removal. This closeup shows a little more detail of what I'll be cleaning up.



I did a google search for the Washing soda, and the only place I found that possibly had the stuff locally was a high-end grocery store. I even called the Hardware stores in the area that I will frequent when looking for obscure, oddball items, to no avail. So, as luck would have it, later in the day, I ended up at the local "new school" hardware store to get parts for a screen door repair. I mantioned the washing soda by name brand to the kid helping me. After giving me a blank look, he turned, walked away, and returned 1 minute later, holding the prize in his hands, surprised as he was, as he had never heard of the stuff, and pleased that he was able to meet my needs. The price for the box pictured below was $4.79, plus tax.



So the plan is at this point on hold because I need to source a suitable sponge for the experiment, and I think that natural cellulose sponge will end up being the ideal medium for the job (that's the kind that comes new flattened out, and expands to it's full size when initially soaked). But will go as follows:

Make up the solution, as specified by DaveO @ 1 TBSP soda/1 Gallon of Water.
Soak sponge in solution.
Place solution-soaked sponge on top of rusty machine surface.
Place anode on top of sponge (I have a piece if bare steel for this)
Connect the battery charger, red to the anode, and black to the machine near the area to be treated
Fire it up and see what happens.

Predictions anyone?

[DaveO]

Cool! I'm glad it inspired you. I paid about the same for washing soda (but it was more with shipping) and I was thinking I could send you some, but it might not be a smart idea to send white powder through the mail these days. At least you can use it in the laundry later on.

That jointer is an excellent find, and I predict success, of course. The only difficulty I could foresee is having to move the sponge from spot to spot, and having overlapping squares showing varying degrees of rust removed. Might make it difficult to get uniform results over the whole surface. Maybe a towel instead, to cover a larger area?

[jerky]

thats a beautiful find! i love to see old machines like that. maybe you can fab up a gaurd for that belt because that just screams " lose your arm here". yes i know its on the back, but still, accidents do happen. and it gives you an excuse to bust out the welder whist your rust removal is taking place

[hooda]

How long should the process take to show results? I know this may sound like a difficult question to answer, just wondering if it's seconds, minutes, or hours til We see results start to happen.

[DaveO]

With full immersion in the electrolyte, I'm guessing 20 - 30 minutes would be sufficient. But a sponge or towel is likely way less efficient, so likely will take longer. I've never tried the sponge / towel method. I'm wondering if you need to keep a supply of electrolyte to replenish the fluid in the sponge if it dries out.

[ogorir]

I wonder if you could improve your rust removal 'cell' by cutting the bottom out of a gladware containter that's the same size as the sponge and hot-gluing some soft rubber around the bottom. you should be able to get the sponge more saturated that if it were just sitting in open air. the more solution, the higher the electron mobility will be and the faster it will work.

[DVA]

That is awesome that some soda ash, water and a bit of electricity can clean rust that well. I wonder what this would do to mill scale on metal? I would assume that if it is leaching the rust that it will also pick up base material as well.

[sportbike]

That is awesome that some soda ash, water and a bit of electricity can clean rust that well. I wonder what this would do to mill scale on metal? I would assume that if it is leaching the rust that it will also pick up base material as well.

It shouldn't "remove" the base metal. the reaction should only occur where there is rust as it is basically converting the rust back to iron.

Works in much the same way as a ruse convertor that can be sprayed or brushed on. With those, there is a black layer left behind, which probably occurs with this as well, but is sort of flushed away by the wet liquid.

[redbeard]

That is amazing that it worked that well with a layer of plastic scrubby on one side, most of the scrubber stuff I've seen seems like it would be a good insulator. Have you considered doing a control patch without the charger hooked up to see how much of the effect might be purely chemical?

[hooda]

So, I did the experiment this afternoon with the help of my hetero life-partner, Tim. We set up the jointer, out in his driveway.


I mixed up the solution, using the rate of 1/2 cup of washing soda to 1 gallon of hot tap water. I soaked the sponge in the solution. All I had available for a cellulose type sponge is one of the smaller ones with the scrubby stuff on 1 side, but we decided to give it a go.


Placed the sponge on the table.


Battery charger negative to the piece being de-rusted, positive to the anode (an old piece of steel that I minimally scotch-brited. Plugged in the charger in the 2 amp mode, and waited 20 minutes. When we lifted the sponge, this is what we saw.

[hooda]

So, last night I continued with the experiment. I used the same base, and started with a different sponge. I used the same concentration of electrolyte (1/2 cup/gallon). The first picture is with a larger sponge, and the charger set to 10 amps after 20 minutes. I checked the part every 5 minutes, and noticed that I could see the progress. This particular section appeared to have had something wet placed on it at some point that caused the rust to set into the metal a little deeper than the rest of the part. The light, uniform rust was gone at the 10 minute mark, but the deeper sections seen here took the full 20 minutes for the process to show its full effect.



Something I noticed is that when I switched from 2 amp to 10 amp, the meter only barely moved, but the charger got louder, when I pushed down on the anode with my hand, I would make the meter go up, but I believe that using a dirty old piece of metal for the anode (I used the same piece of steel from the initial experiment for the anode), covering only the small area that it covers, is effecting how much current the setup will draw, and ultimately how much time it will take to work.



Below is the larger sponge I used, and the plastic pitcher I mixed my solution in. 1 minute in the microwave to heat it up, and easy to add solution to the sponge during the process, as I believe that keeping the sponge fully saturated has an effect on the process. The smaller sponge was the control experiment soaked in solution, and set on a rusted section off to the side without current. I checked the control experiment every 10 minutes for 1 hour. Other than appearing like it was washed off with plain water, the solution had ZERO effect on the rust without the electrical process applied.



I will post the final results when I get a chance.

[sportbike]

Something I noticed is that when I switched from 2 amp to 10 amp, the meter only barely moved, but the charger got louder, when I pushed down on the anode with my hand, I would make the meter go up, but I believe that using a dirty old piece of metal for the anode (I used the same piece of steel from the initial experiment for the anode), covering only the small area that it covers, is effecting how much current the setup will draw, and ultimately how much time it will take to work.

Some of that is likely due to the strength of the electrolyte solution as well. A stronger solution would carry more current, along with a better anode.

[DaveO]

when I pushed down on the anode with my hand, I would make the meter go up

I wonder if this is because you're compressing the sponge, and reducing the volume of the holes within the sponge, and enabling more electrolyte fluid to come into contact with the anode.

I believe that using a dirty old piece of metal for the anode (I used the same piece of steel from the initial experiment for the anode), covering only the small area that it covers, is effecting how much current the setup will draw, and ultimately how much time it will take to work.

My guess is "absolutely right". A shiny clean anode would work better, just as removing built up crud from a battery terminal helps power flow better.

Nice work taking a methodical controlled approach!

[hooda]

Sorry, My computer wouldn't let this darn pic into the last post.



Bottom line is that with a little experimentation, I can see tha potential for this being applied in numerous other ways. Thanks, Dave O for the idea!! Anyone who wishes, feel free to ask questions.

[67cudafb]

That is amazing, I would never believe that would work. Like I said there is smart people on this site. Who says you can't teach an old dog new tricks?

[hooda]

So, I finished the piece late last night and this morning and below is the end results. I has to post it in 3 photos to get the clarity I wanted to show.







This is with no additional sanding or oiling, just the process. The bottom pic shows the fence that hasn't been done to better illustrate the effect of the process. I noticed that even though the rust is gone, there's still a "roughness" left after treatment. After photographing, I tested a small part with some scotchbrite hand pad, and it made the surface silky smooth You will notice several things. First, the lower right corner where the initial experiment is the cleanest spot on the part by a wide margin.

I changed too many things from that section to the rest of the part to pinpoint what went different. Consider that I had :A bigger sponge, higher concentration of solution, different amperage, different time and temp, and it's unclear, but my best guess is that it was mainly that I wasn't getting enough current through the setup.

I noticed that the anode left a "fingerprint" in the spot it was placed for the section. I cleaned some more of the rust off the anode in an effort to get more current going, but it didn't have much effect.

Due to the list of things pressing me, the main point shifted into just getting the job done by about 1:00 AM. Here's my advice to anyone who wishes to give this method a go. (and if you do, please post your results for us to see)

First, on the solution, use a lower concentration, The 1 tablespoon per gallon that DaveO used in the inspiration for this may give the solution more "room" to reach the oxides we're trying to get to.

Next the sponge. If you look at the lower right corner, it's CLEAR that the smaller surface area responded better, all other variables aside. I would go for about a 3 x 5 size sponge to start with. One more thing, I wonder if wringing out the sponge periodically might possibly flush away the contaminants being generated, thereby allowing the process to take a better effect.

On the anode, I would suggest trying stainless steel and sizing the anode to match the sponge, to maximize the electrical activity. If stainless isn't an option, a piece of regular mild steel, immaculately clean, and matching the size of the sponge. I'd really like to try a round piece, using sheet metal as the anode, and wrapping it with the sponge in between. As far as current. I believe that getting current to flow at the highest level possible is the key to the whole thing, and if one could coax 10 amps out of the setup, the oxides would disappear in a matter of 2-3 minutes.

When I have more time, I'll play with the process and post more, but for now, thank you DaveO for the inspiration.

[redbeard]

That's awesome. Thanks for the time and effort you took to experiment and refine the process, it makes me wish I had something rusty (and a battery charger) to try this with. Maybe I'll have to try it with an old computer power supply.

I think your observations/theories on the anode are probably correct, a more uniform current density certainly wouldn't hurt anything and rinsing the sponge and resoaking it with fresh electrolyte will eventually be necessary.

[DaveO]

Just a reminder: Hooda used a sponge as a workaround because the jointer was too large to put in a vat. The ideal situation is to immerse the rusty part and the anode in the electrolyte fluid.

[hooda]

So, while I was performing the experiment, I was simultaneously installing a tow bar on a '94 caravan, which I then towed home, a 75 mile jaunt. This gave me some time to kick back in the driver's seat and think. And my thoughts went to "what are some uses for a process like this?"
Well, In my opinion, this would be PERFECT to de-rust antique machinery that one wants to keep as original as possible. Now, the subject of the experiment, an old jointer-planer, if I keep it, will get a different treatment altogether, because for practical purposes, I want an immaculately clean surface. That means I will take advantage of the fact that I have a beautifully uniformly rusted piece to finish the initial round of experiments on, then, I will use a more agressive approach (red scotch-brite HAND pads) to obtain a flat surface that is clean enough to put an expensive piece of exotic wood through.
If it were a highly valued antique, I can see where one could use the electrolytic approach, and manage to preserve that beautiful, aged, grey patina, sans the rust.
The biggest mistake people make in this situation is being the "know-it-all" and "fixin' up" an old piece by going after it with those DARN roloc discs (I'm going to start a thread just for these), wire wheels, sandblasting, stripping decades of aging, and the dollar value associated with it. I just saw an old pawn-show rerun where a guy polished up an old WWII knife, and basically polished away 90% of it's value.
Using this process avoids that better than any other cleaning procedure that I've seen. I want to see others go ahead and try it. Let me know if you're interested and can't find the washing soda, I may be willing to send you some.

[DaveO]

The biggest mistake people make in this situation is being the "know-it-all" and "fixin' up" an old piece by going after it with those DARN roloc discs (I'm going to start a thread just for these), wire wheels, sandblasting, stripping decades of aging

Around here there's a lot of Civil War battlefields (such as Manassas and Bull Run) and every now and again you hear about somebody finding a relic and cleaning it up to within an inch of its life, and nobody will touch it because it looks too new.