Rust Removal via Electrolysis – An Overview

On the way home from work last night I was reading the woodworking sub-reddit and I noticed several posts about rust removal.  It seems like very few people are aware of how cheap and easy it is to use electrolysis to remove rust from tools.

Over the past few years I have used a pretty simple setup to strip the rust / paint off of my tools and I have been VERY happy with the results.  That said, I am in no way shape or form an expert on the subject so I do not know if this is appropriate for any collectable tools, but it works great for my users and involves little if any harsh chemicals or fumes.  I have never used EvapoRust but I used Navel Jelly and other similar products when I worked on the restoration team at the USS Missouri Museum and this process is safer and cheaper.  Plus there are no air-born particulates.

Electrolysis uses direct current (DC) power to transfer material from one piece of metal to another via a solution.  In our case, we are transferring Iron atoms from a sacrificial piece of metal to the tool in order to convert some of the “Red Rust” (ferric oxide) to “Black Rust” (magnetite).   The piece of metal to be cleaned is connected to the positive (red) terminal and the sacrificial piece is connected to the negative (black) terminal.  As the electricity travels through the solution, iron atoms are transferred from the sacrificial steel to the tool (along with some oxygen from the water) changing the Fe2O3 into Fe3O4.   In the process, the red rust that is not converted into black rust will come off and drop into solution.  Black rust is non-destructive (it does not flake) and it does not hold moisture like red rust so it actually helps to protect the metal from further rusting.  I’m not a chemist so take this all with a grain of salt.

The supplies you need:

-plastic container (I use a bucket or boot tray depending on what I am cleaning)

-12 volt DC power supply (I use an old laptop power supply)

-Baking Soda or Washing Soda

-Scrap Iron or steel (no stainless or galvanized)

-Wire

-Alligator clips (optional)

-Scrotchbrite sanding pads for cleanup (I use the “between finish coats” grit)

Power Supply

Most of the setups I have read about online used car batteries or battery chargers but I use a laptop power supply that I was able to get one from my IT department for free since it was being sent to recycling.  While they are lower power than the typical battery charger they are smaller, sealed (i.e. water resistant), and in my case free.  The lower power simply means the parts need to stay in solution for a longer time and I have a feeling there is less chance of damaging the parts being cleaned.

The modifications are simple, cut off the plug that goes into the laptop and identify which of the wires is positive and which is negative (the internal wires may already be color codes otherwise use a multi-meter).  I then connected longer color coded wires (in my case I used heavy gauge speaker wire from radio shack) and attached an alligator clips to make it easier to connect the parts being cleaned.

The Cleaner

May of the posts I read recommended using “washing soda” mixed with the water however I find baking soda is much easier to come by and since “washing soda” is simply a stronger version of baking soda you  can simply use more of the baking soda.  Typically I use around a tablespoon of baking soda per gallon of water, but I am not precise in my measurements.

Sacrificial Metal

For the process to work, the negative terminal needs to be connected to a piece of sacrificial steel or iron.  I have read that if stainless steel (or other steels containing chromium) is used the process can release toxic gases and will contaminate the water with heavy metals.  Additionally, you should avoid galvanized steel as you may end up Zinc plating your tool.  I typically use re-bar because it is cheap and easy to find but I think cast iron works faster (maybe the porous structure increases surface area?).  What is most important is the piece of metal should have a lot of surface area as this will dramatically speed up the cleaning process.

This piece(s) of metal will eventually become unusable due to the buildup of corrosion however in my experience you can use them for multiple cleanings.

The Process

Note: we are dealing with electricity and water together so be careful.  Connect everything with the power supply unplugged and if possible, use a GFI outlet.

Getting things started is simple: connect the part to be cleaned to the red wire; the sacrificial metal to the black wire and submerge both in the solution of water and baking soda, making sure the two pieces are not touching.  Now set you bucket outside and plug it in (this process can release small amounts hydrogen gas which is flammable in enclosed spaces so do this in a well ventilated area), you should see a bubbles forming on the surface for the part being cleaned or streams of bubbles reaching the surface within a few seconds.  Now sit back and wait.

How long?  That is the 64 thousand dollar question.  It is going to depend on the strength of your power supply, the level of corrosion, the strength of your cleaning solution, the surface area of your parts, etc.  I will typically check on the progress every few hours but seriously rusty parts I often leave overnight.

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Note the use of a nickle plated bolt, DON’T DO THIS.

 

When the parts are done, they will be black in color and you should see none of the telltale texture of rust.  Once it comes out of the solution you can either leave the black magnetite in place or remove it with a fine grit sanding pad.  You then want to dry the part quickly and apply oil as flash rust can appear quickly.

 

Sources:

http://myweb.tiscali.co.uk/andyspatch/rust.htm

http://www.woodcentral.com/cgi-bin/readarticle.pl?dir=handtools&file=articles_363.shtml

 

 

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Wooden Smothing Plane – H.G. Stilley

Some of you may remember the rotten tool chest I found on the side of the road a few weeks back and the smoothing plane I found inside.  Well this week my elbow was giving me some trouble so rather than milling up the maple for my leg vise I decided to get it up and running.  Here is the starting point:

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After taking everything apart it looked like the components were mostly intact so I started following the process the Slightly Confused Woodworker used on his English plane but instead of using a plane to flatten the sole I used heavy grit sandpaper glued to a marble slab (I encountered some serious tear-out when I tried to use my sharpest plane).  The sole needed a fair bit of flattening.

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The blade and cap iron got a bath in my electrolysis setup and came out looking pretty nice.  A previous owner had take the time to flatten the back of the blade so it really only needed polishing, but the chipped edge was going to require some grinding.

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While I was waiting for the BLO to cure, I decided to look up the maker H.G. Stilley since he was a local.  There was little online other than he moved to San Francisco during the gold rush and that his planes were rare. I also found an old posting from a collector near Carmel, California looking for any planes made by this maker so I emailed him a picture to see if he had any info.

What I was able to find online:

  • Born in Delaware
  • Moved to SF during the gold rush and at one point lived a few blocks from my office
  • Census records show him living in SF, Oakland, and the gold fields
  • Was a member of the Yerba Buena society of Odd People (S.F. has always bee a bit different, look up Emperor Norton sometime)
  • Lived to the age of 85

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After asking me a few questions he ended up offering some money for the plane so he could add it to his collection so unfortunately I will not get to finish the restoration and actually get to use it, but it will be going to someone who appreciates it.

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It still needs a coat of wax and to be sharpened but it looks pretty go to me.

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Upgraded Electrolysis Setup

Given that I have several tools that will be needing rust removal I decided it was finally time to upgrade my electrolysis setup to use rebar.


I started with some small poplar strips I had laying around from some previous project and built two parts of a hexgon which are bolted together (this wil make it to the hexagon can fit in the bucket for storage).

  The flats got 1/2 inch holes in the middle which held the rebar and pipe ground clamps hold the rebar in place.  I only had 4 pieces of rebar but the plan is to eventually have 6. 

The bade and chip breaker from the coffin smoother I found got suspended from a 1/2 inch dowel with notches and into the usual bath.

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After about 4 hours in the bath the blade looked pretty good.

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Restoring a Stanley #10 – Part 1

Here is my Stanley #10 which was part of the batch of tool I purchased from a collector early last year (the same one I bought Big Bertha from). He sold it to me as a discounted price due to its poor condition: it was covered in rust, the tote was broken, and the mouth had obviously been chipped and badly refiled. I did not have time to deal with most of the issues when I purchased it but did nuke the rust on the blade, chip breaker, and cap-leaver. I’m apparently bad at before pictures so here is the plane as it looked on Friday:

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Most of the Japaning was missing or loose and there was rust all over the plane body. Since I already had the electrolysis gear out for the vise the frog and the body went into the bath for a long soak. 6 hours later I hit them with a brass brush and then back into the bath for several more hours (I’m not sure if my sacrificial iron is getting used up or if it’s because I am using Washing Soda instead of my usual baking soda but the rust removal went much slower this weekend).  After the last soak I used a “between finishes” sanding pad to remove the black residue left on the parts and placed them into a 225 degree oven for 10 minutes, letting them cool inside the oven; this fully dries out the parts in preparation for painting. Once the parts had cooled down there was a fair amount of flash rust that I removed with a wire brush mounted to a Dremmel Multi-tool (I don’t have a bench grinder yet).

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For applying the new finish, I followed Rex Mill’s plan using engine paint with the addition of petroleum jelly on the areas where paint is not needed, as recommended by Bob Jones.

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Before                                After Flash Rust Removal                                 After Painting

Tonight I will wipe/scrape/sand off the excess paint and access the straightness of the plane mouth.

I also started repairing the broken tote. It’s not a clean break and it had a previous railed repair so I decided to use a compilation of the techniques found on Rex Mill’s site. First I scrapped out as much of the excess glue that I could, and then I drilled a series of small holes in each face of the break (the theory being that this would give more surface area for the epoxy. A quarter inch dowel rapped in tape and coated with petroleum jelly lined up the two parts and I smeared 5 minute epoxy into the holes on each face, squished the two parts together with my fingers, and added a bead of epoxy on the outside to fill the chips/gaps along the break. Once the epoxy was 90% set up I pulled out the dowel and continued to hold the pieces together until the bead was hard to the touch.

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I forgot to take a picture of the glued up tote but I will make sure to do so before I sand it down.

Vise Restoration – part 1

After looking over the vise I purchased on Craig’s List I decided it just needed some minor rust removal.  It looks like it was rainted at some point (there is paint on the parallel bars near the front) and while I don’t know what is under that paint, overall the surface looks pretty good.  Most of the rust is on the bottom on the parallel bars and the screw so I decided to start with some electrolysis rust removal.

 

Before

I hooked it up to the electrolysis machines and put it into a bucket of water and washing soda for around 4 hours.


After a brief scrub with a sanding pad and a wire brush things are looking considerably better.

After

I put on some Camilla oil and tomorrow I will use abrasives to clean off the rest.