Tuesday, January 15, 2013

Removing Rust with Electrolysis

In a recent post, I talked about the benefits of hand tools and how there are some really good finds out there to be had.  Let's say you are looking at some tools at a yard sale, thrift store, or other second hand shop, and you find something you are really interested in purchasing.  After testing it out, it seems to suit your interest very well, except it is covered with rust.  A little surface rust is no big deal, some steel wool and an oil-based lubricant will clean it up very well.  However, major rust can be a real downer on a prized piece.

I recently came across an anvil that my grandfather frequently used long before Ronald Reagan entered politics.  After he passed away, my grandmother had covered it with water-based yellow and used it as a conversation piece in her garden.  Left untouched for many years, the surface rust was considerable.  After some research, I considered electrolysis to be my preferred choice of rust removal.

Taking proper precautions, electrolysis is very simple and is one of the most environmentally friendly methods of rust removal.

Why Electrolysis?

Electrolysis would remove not only the rust, but also all paint on the anvil, leaving a nice shiny bare metal surface.  In addition, electrolysis would give me much greater control over how much material would be removed and how evenly I can remove it.  With a wire brush I would be challenged to leave the smooth surface I desired, and although chemical rust removers may work well, getting into the small crevices and hard to reach places could present a challenge.


Remember, as the name "electrolysis" suggests, you will be working with electricity.  If that makes you uneasy, stop and find another method.  I really suggest having a commanding knowledge on the basics of electricity before you go any further.

Second, there are some mild chemicals involved with this process.  While there are no strong acids, we are using washing soda, which could cause irritation or more severe problems if it comes in contact with skin or eyes.

You should take proper precautions when dealing with any chemicals, including proper clothing, eyewear, proper ventilation, and chemical resistant gloves.  The chemical reaction will make hydrogen gas, which can be flammable.  Never do this near pilot lights or any other type of fire or flame.

In addition,  while you may understand the intricacies of this operation, it is important this process be done in a secluded area away from others who may not understand its danger.  Children and animals should remain away from this area for the entire process.  My dog has a habit of eating cat poop, so I could imagine her trying to drink the water if given the opportunity.

Not for All Tools

While electrolysis is a great method of rust removal, it is not for all tools.  I would not suggest sticking anything which could be damaged by water into solution.  Any types of wood, basic electronics, or moving parts must be removed.  This method effectively works best for bare metal.  Some disassembly may be required to efficiently clean your tools.  

The Setup

For assembly of the electrolysis tub, gather the following supplies:
  • 12 gauge wire
  • steel rebar
  • scrap steel wire
  • plastic 10 gallon tote
Cut fours pieces of  rebar that are 1-2 inches longer than the height of your plastic tote.   To secure these as posts in the four corners of the plastic tote, drill two holes near the top of each corner, loop the wire trough the holes and around the post, then twist the ends together snugly.

After the posts are secure in each corner, take four pieces of copper wire and strip about two inches off each end.  The wires should be slightly (25-50%) longer than the full length of your plastic tote.   Wrap one end of each wire securely around the top of each rebar post, then twist all four ends together at the top, forming a pyramid shape with the wires.  These wires must stay above your electrolysis bath during the rust removal process.  Congratulation, you just formed the anode, which will connect to the red clamp on you battery charger.

Now you will create the cathode piece, which will connect your work to the black wire.  The best method I found is to suspend your rusted metal in the water with a bare copper wire wrapped around it.  In the picture to the right, I wrapped the anvil in bare copper, then secured this wire to the white wire, wrapped the 1x2 scrap of wood.  Fill your tote with water, and one tablespoon of washing soda per gallon.  Stir it up and completely submerge your rusted tool in the solution.

Turn On the Juice

Be sure your battery charge is unplugged.  Connect the red clamp to the twisted wire at the top, or the anode.  Connect the black clamp to the wire leading you your rusted metal.  Now get ready for the magic to happen and plug in your battery charger.  I used the setting for 2 amps on 12 volts.  Stand back.  Wow . . . really . . . nothing?  Do not be fooled, it's happening, but very slowly.  Do you see bubbles forming on your tool?  That is hydrogen gas escaping.  The first time I did this, I didn't see the bubbles.  So I added more washing soda, with the battery charger turned off of course.  When you see the bubbles, you know it's working.  Now, don't touch the water and leave it alone for a while.

Check it every hour or so.  Is there muck floating on the surface?  Then the electrolysis is working and the rust is coming off your tool.  In my case, the paint was coming off as well.  After about four to five hours, I cut everything off, pulled the anvil out, and gently scrubbed it with a steel brush.  The bare metal underneath was now showing.  I dropped it back in the solution and plugged everything back in.  Every hour or so after this, I pulled out the anvil and brushed some more crud off until I had a really clean final product free of paint and rust.

Over 40 years later and the anvil was looking great and ready to use again.  The last step of any electrolysis rust removal is to prevent future rust.  Paste wax, linseed oil, laquer, or whatever method you wish is fine.  I put a decent coat of AmsOil to make this anvil project complete.  You can also save the solution after you are done, and reuse it on future projects.

New Life

As previously mentioned in The Importance of Old Hand Tools, the durability of hand tools over 30 years old is very good.  With electrolysis as another weapon in your arsenal of antique restoration methods, you can safely and efficiently remove rust from many classic pieces.  Find your next gem in someone else's rusted pile of long forgotten tools, bring it back to life, and put it to use in your own shop.