Shopsmith Restoration #9: Electrolysis for Rust Removal

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Blog entry by PG_Zac posted 04-27-2010 09:33 AM 7447 reads 7 times favorited 14 comments Add to Favorites Watch
« Part 8: Quill Dismantling Part 9 of Shopsmith Restoration series no next part

This series has been quiet for a while, as I’ve been buying replacement parts off eBay and dealing with several small(ish) technical issues. The members of the ShopSmith owners’ forum have been extremely helpful. My thanks to the LJ members who pointed me to that forum.

Here is my experience with removing rust by Electrolysis and I’m sure that many LJ’s can benefit using this technique for tool restoration. If you have any questions, just ask and I’ll do my best to help. I’m sure that this isn’t the first LJ posting about this technique, but it is the most recent, and new members could find this helpful.

Basic setup:-

I took 2 scrap pieces of painted angle iron from old shelving.

Cleaned the inner faces and attached cables.

I took my quill housing and wedged a cable inside.

Then placed them in a bucket and electrolyte like this.

Next I connected the battery charger Black to quill & Red to angle irons

I applied power, and nothing happened. At least nothing happened in the bucket. The charger hummed, and that was all. I moved the quill closer to the scrap – nothing. I moved the quill to touching the scrap – nothing. I switched the charger from 3A to 15A – nothing.

So I dismantled the setup and pondered overnight.
Was it the Electrolyte solution? Maybe the issue was the 1 tablespoon per gallon I’ve seen on some instructions.
Was it the charger? It is a bit old, and has been incorrectly connected a few times.

A few possible answers surfaced in my brain over the next few hours, until I had a route mapped forward.

Step 1: Test the charger on a battery I know will need boosting – CHECK
Step 2: Enrich the electrolyte to 1/2 cup per gallon as seen on other instructions – CHECK

I made these adjustments and connected the system again.
I applied power and (drumroll please) ... ... ... NOTHING.

Then a small little background idea pushed forward in my head – This charger has an automatic cut-off when the battery is full. Maybe it also has a protection circuit of sorts that only allows it to work if there is a battery connected.

The next step was to use a battery instead of a charger on the cleaning circuit to see if the charger was the problem.

I connected the battery to the circuit and … ... Hey presto – BUBBLES

I then connected the charger to the battery to keep it charged it while the battery was working on my quill. The battery and the work are connected in parallel.

Six minutes after starting, this is the surface of the electrolyte

This is the charger – As you can see here, the system is drawing between 9A and 12A

Goop Soup anyone?

The temperature of the liquid went up from the ambient 25 deg C to 42 deg C


After Electrolysis

After 15 minutes with sandpaper and steel wool.


This process has reduced my work time down to half or less. What used to take over 4 hours, now takes less than 2 hours including electrolysis.

-- I may be schizophrenic, but at least I have each other.

14 comments so far

View bigike's profile


4052 posts in 3289 days

#1 posted 04-27-2010 12:20 PM

wow great job! ;)

-- Ike, Big Daddies Woodshop,

View PG_Zac's profile


368 posts in 3389 days

#2 posted 04-27-2010 01:45 PM


I’ve read that any Sodium product will be a good electrolyte for this process. Sodium Bicarbonate (baking soda), Sodium Chloride (table salt) etc. but I read that Sodium Carbonate (washing soda) is apparently the best. I found some washing soda amongst the laundry detergents at Checkers and used it for this test.

Yes, the angle irons are connected together to the charger’s RED cable and the battery’s positive (+).

-- I may be schizophrenic, but at least I have each other.

View PurpLev's profile


8535 posts in 3649 days

#3 posted 04-27-2010 05:03 PM

looks like great progress

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View stefang's profile


15881 posts in 3334 days

#4 posted 04-27-2010 05:39 PM

Great blog Zac. I wonder if it will eliminate wrinkles too?

-- Mike, an American living in Norway.

View Woodstock's profile


253 posts in 3288 days

#5 posted 04-27-2010 10:11 PM

Thinking out loud for a second. I wonder if some sort of better quality sacrificial metal such as a small chunk of stainless steel plate from the scrap yard instead of something soft like angle iron from the borg would have a better/longer lasting result?

-- I'm not old. Just "well seasoned".

View SST's profile


790 posts in 4195 days

#6 posted 04-28-2010 03:17 AM

Great write up & pix. I’ve used this process on old planes with great success. I use washing soda. I’ve thought of making some wood troughs so I can do Shopsmith way tubes, but I’m out of unrestored Shopsmiths right now. I figure that if I get a pretty tight fit on the wood & let it soak up water & swell I could make it work. I guess lining it with plastic from a cut open garbage bag would also work. Good luck with the rest of the project & post more pics. -SST

-- Accuracy is not in your power tool, it's in you

View eccentrictinkerer's profile


38 posts in 3028 days

#7 posted 04-28-2010 06:22 AM

There are postings on some sites that warn against using stainless steel because of the potential for heavy metals being leached out of the SS. These metals could be dangerous to our water supply.

I haven’t investigated the claims, but thought someone (chemist?) might have an idea if this true.

View PG_Zac's profile


368 posts in 3389 days

#8 posted 04-28-2010 11:06 PM

SSTom – hopefully I’ll get a chance to try this out on a was tube soon. I’ve already sanded and painted the bench tubes, and I almost finished sanding a way tube before I managed to get the electrolysis right.

Eccentric – I have also read that stainless is a bad idea due to hexavalent chrome being released, so I won’t even take that chance as our only water supply here at home is from our own borehole.

-- I may be schizophrenic, but at least I have each other.

View JJohnston's profile


1622 posts in 3291 days

#9 posted 05-01-2010 08:48 PM

Here’s a tank I put together for cleaning rifle actions & barrels, but it would work equally well for anything long and thin, like the way tubes. It’s a piece of scrounged 5” PVC pipe with (bought) caps. Other diameters from 3 to 6” would work also. It’s about 3.5 feet long.

Glue on the caps, then cut out a rectangular opening of width about 1/4 of the circumference, from cap to cap. If it’s thin-wall, split the cutout down the middle and glue it along each edge of the opening to stiffen it. You can make a V-block for each end, or just dig a shallow trench to keep it from rolling. I don’t know why the white caps look purple, except that the sun is reflecting directly off them.

Drill a drain hole in one end near the top. No plug is necessary; the contents will stay in place until you tilt the other end up. Without the drain hole, you’d never get the contents out completely.

Make an optional parts rack by cutting another rectangle of pipe about the same length as the hole in the tank and drilling holes in it; make the feet by cutting some of the pipe into small rectangles and gluing them into a stack, and glue it onto the bottom. These feet are 6 layers thick; use whatever you like.

Here’s a shot with the flash on that shows the parts rack in the tank. There are 4 feet on the parts rack; the interior ones are where the holes have the bigger space between them.

-- "A man may conduct himself well in both adversity and good fortune, but if you want to test his character, give him power." - Abraham Lincoln

View PG_Zac's profile


368 posts in 3389 days

#10 posted 05-02-2010 09:52 AM

Thanks JJ.

I was thinking of a 5” pipe for my way tubes, and this gives me a great insight on what features to include when I make mine. One question though – how do you keep the electrode from touching the workpiece?

-- I may be schizophrenic, but at least I have each other.

View JJohnston's profile


1622 posts in 3291 days

#11 posted 05-02-2010 06:24 PM

You mean because the bottom of the tank isn’t flat? I hadn’t thought of that. I’ve never used my tank for electrolysis, only for “soak and scrub”. I suppose a flat insert, instead of one made from pipe. Or, you could bridge across the opening and suspend the electrode in the solution. Or, size your feet so the electrode fits under the parts rack (would that work? Do the parts have to have “line of sight” to each other for the ions to flow?)

-- "A man may conduct himself well in both adversity and good fortune, but if you want to test his character, give him power." - Abraham Lincoln

View PG_Zac's profile


368 posts in 3389 days

#12 posted 05-03-2010 09:17 AM

I believe the parts do have to be “line of sight”, but I haven’t tested that yet. From the parts I’ve done so far, I suspect that there is a small amount of “around the corner” activity happening, but not much and certainly not far around the corner.

-- I may be schizophrenic, but at least I have each other.

View Jayp413's profile


69 posts in 3010 days

#13 posted 05-20-2011 03:57 AM

Great series! Anymore progress and pictures??? Would love to see where your at!

View FeralVermonter's profile


100 posts in 1971 days

#14 posted 01-19-2013 02:11 PM

I’ve been looking at electrolysis for a while, just haven’t gotten started because I don’t yet have a solid idea of what’s going on in the tank, and I don’t usually start a project until I have a solid conceptual floor to work off of… but also because something in my gut has been telling me that there’s more to it… more to it, as in danger.

First off, from what I’ve read, using stainless steel is VERY toxic, and that furthermore dumping of the post-electrolysis fluid is illegal. Couldn’t tell you why, exactly, but it’s something mentioned on nearly every resource I’ve found so far. Why risk it?

But mainly I’m writing to re-share a post from another LJ electrolysis discussion which discusses what sorts of chemicals are found in the post-electroylsis fluid (post #27 on this thread

Electrolysis may be “easy,” but there’s really a lot that a responsible person should know, before getting started.

(Thanks to chrisstef and Sodabowski):

Well, basically, all the crap you put in there in the first place will always be there in the end.

Just a bit WORSE.

The acidity of the bath can raise as gasses start to bubble and dissolve in there (hydrogen WILL be produced and WILL dissolve), and you add to it all kinds of metal oxydes from whatever crap is on the metal part firsthand. Also, the paint used for metal can contain boatloads of very dangerous stuff, like LEAD, which is an absolute poison for… whatever.

I still have some copper oxides from a small electrolysis experiment I did waaaay long ago when a teen (12 or so) in a test tube. These oxides can be very stable if you know what’s inside, but with iron and generally speaking industry-made tools, moreover vintage stuff, you never really know what’s inside. The cast iron could be of the unpurified sorts and contain all sorts of poisonous metals, and you don’t want them back in the biosphere, or in your garden (try growing anything edible afterwards… I WOULDN’T).

Best thing to do with such baths is to leave them to evaporate, scratch the dry residue and keep it in a glass container until you have enough accumulated (say a full jar) to bring it to a safe disposal facility. At least that’s what I would do if doing big time electrolysis with tools, and that’s about what they do at the university’s chem labs, when they aren’t sure what’s inside and they can’t neutralize it themselves.

All depends on whatever parts you put in there, and what you add to your bath for it to conduce electric current. I would use caustic soda for it’s easy to neutralize afterwards using hydrochloric acide (which would end up being salter water once you’ve neutralized the solution). You have a little math to do to ensure the proper quantities to end up with a neutral solution, but it’s by far the best eco-friendly solution (using table salt from the beginning is OK but it’s loaded with other minerals and as such it produces gunk on its own and can leave chloride inside the metal parts, which would cause them to oxidize after the fact if you don’t rinse them properly immediately after the electrolysis).

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