# Oxalic Acid Rust Removal for old Plane Restoration



## EricD (Jan 17, 2013)

I bought this Stanley 9 ½ block plane for $5 at a MWTC meeting. It had rust on one side of the body and the blade was replaced with a “Craftsman” blade. A perfect user at the right price (first picture).

I am not going to convince anyone of OA’s safety, for me the risk is minimal especially compared to aerosol paint, organic vapors, paint stripper and sand blasting, all of which I am very familiar with. The toxic dose of OA is 600mg per kg of body weight. For a 220lb person, the toxic does is 60gms or ~2 ounces. Try drinking 60 gms of your favorite paint/mineral sprints etc. 

OA removes the rust on iron based metals. It will eat zinc and chrome plating if the exposure is too long/strong and the plating is thin. For this resto I am only soaking block plane’s body in OA. The rest of the plane's parts have a nice patina so I removed everything from the body. OA will not damage paint or japaning, only the rust is removed. I purchased OA at my local hardware store, it’s used to wash wooden decks and is known as "wood bleach". Second photo is of OA in hardware package, ~$8.

I prepared a small bath of Oxalic Acid (OA), I am using less than 2gms per bath, the container is an ice cube tray. It’s important to keep the OA bath warm or it will not react with the rust. In the third picture you can see the plane body soaking in OA. Later on I added a small 15W aquarium heater to maintain the bath’s temperature at ~80*F as the air temp in my work area is ~65*F.

As the rust started coming off I pulled the plane body out of the bath at ~15 minute intervals, rinsed, then wet sanded the rust with 400 grit paper. This speeds the process along by breaking up the top layer of rust and allowing the OA to work on fresh rust. When all the rust was gone I wet sanded the all of the exposed cast iron section of the plane body to have a uniform finish.

Fourth photo is the plane body after the process is complete. I have also washed off the body with a sponge and dish soap. Next step is to wax with some Johnson Paste Wax (fifth photo).


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## EricD (Jan 17, 2013)

*Oxalic Acid Rust Removal for old Plane Restoration (cont)*

Last photos are of the finished product, a nice 9 ½ user ready to be tuned up.


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## ACP (Jan 24, 2009)

That's a beautiful restore. I personally like evaporust, but everyone has their own methods and yours obviously works awesome. Well done!


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## Dave Paine (May 30, 2012)

EricD said:


> Last photos are of the finished product, a nice 9 ½ user ready to be tuned up.


Looks good, nice restore. :thumbsup:

Does oxalic acid eat into non-ferrous metals such as copper, bronze or brass?


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## EricD (Jan 17, 2013)

Thanks for the kind words, giving new life to an old plane is fun and satisfying.



Dave Paine said:


> Does oxalic acid eat into non-ferrous metals such as copper, bronze or brass?


No but it may discolor the finish. I always tear my object down to the bare metal but some folks soak entire bicycle wheels made of brass spoke nipples and aluminum hubs with no ill effects.


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## EricD (Jan 17, 2013)

ACP said:


> ...I personally like evaporust,...


Oxalic acid works by a process called "chelation". I was just doing a little research into Evapo-Rust and I wonder if it isn't oxalic acid based:

from:
http://en.wikipedia.org/wiki/Chelation 


> Products such as Bio-Rust and Evapo-Rust are chelating agents sold for the removal of rust from iron and steel.


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## Dave Paine (May 30, 2012)

EricD said:


> giving new life to an old plane is fun and satisfying.


Yes, I feel the same, and some of my rust buckets have been in much worse shape. :laughing:

I actually picked them up due to the condition. I felt it was not likely someone else would "rescue" these.


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## Dominick (May 2, 2011)

Nice restore job. Looks pretty good. How ironic I'm doing a light restore on a drill press and I'm using electrolysis to remove rust. Ill post some pics a little later. Not to hijack this thread.


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## Dave Paine (May 30, 2012)

Dominick said:


> Nice restore job. Looks pretty good. How ironic I'm doing a light restore on a drill press and I'm using electrolysis to remove rust. Ill post some pics a little later. Not to hijack this thread.


I was wondering if you had got around to working on that Walter Turner you picked at a garage sale for a mere $5.

If I recall the only feature missing was that the table did not tilt. Mine does but I have not used the tilt feature.

After seeing this thread, I may use a jig if I ever need to drill vertical or at an angle.

http://www.woodworkingtalk.com/f27/drill-press-jig-drilling-vertical-46641/

Looking forward to seeing the restore pictures. :thumbsup:


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## Woodwart (Dec 11, 2012)

Beautiful job! :thumbsup:


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## Dominick (May 2, 2011)

Dave Paine said:


> I was wondering if you had got around to working on that Walter Turner you picked at a garage sale for a mere $5.
> 
> If I recall the only feature missing was that the table did not tilt. Mine does but I have not used the tilt feature.
> 
> ...


Thanks Dave. I'm not doing the walker turner. It's a different one I had sitting around before I got the WT. ill start a thread. Stay tuned.


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## tc65 (Jan 9, 2012)

Eric, thanks for showing another method, those came out really nice. I'm curious about the concentration you used. You mixed 2g per bath, but what was your water volume? I'd assume that concentration is somewhat important so as not to get too strong a bath. From your work on bikes (and from the bike forum) is there somewhat of a standard concentration that is used? Or a range of concentrations used depending on the amount of removal needed?


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## nbo10 (Jan 26, 2011)

Whats the purpose of the Johnson Furniture Polish?


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## tc65 (Jan 9, 2012)

nbo10 said:


> Whats the purpose of the Johnson Furniture Polish?


Moisture barrier, and also to reduce friction when planing.


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## timetestedtools (Aug 23, 2012)

great restoration.


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## EricD (Jan 17, 2013)

trc65 said:


> ...From your work on bikes (and from the bike forum) is there somewhat of a standard concentration that is used? Or a range of concentrations used depending on the amount of removal needed?


Someone smart in the ways of chemicals posted the correct concentration on the old Schwinn Forum, I worked it out for 2 gallons and it came out to two heaping tablespoons. I have found the concentration isn't that critical, esp for cast iron and thick Schwinn chrome. For this exercise I erred on the side of weak and went with a less than a level teaspoon for a 1 quart ice cube holder. Since it's winter and the air temperature is low in my basement I bought a 15W aquarium heater to keep the OA bath above 78*C.

OA leaves a *********** residue on everything, interesting to hear the same thing happens with Evaporust. I scrub the plane with dish soap/sponge to remove the white residue before waxing.



nbo10 said:


> Whats the purpose of the Johnson Furniture Polish?


As stated, to prevent rust. Please be aware it's Johnson Paste Wax, not furniture polish. Furniture polish has silicon based stuff in it and can be a disaster for finishes.


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## Dave Paine (May 30, 2012)

EricD said:


> OA leaves a *********** residue on everything, interesting to hear the same thing happens with Evaporust. I scrub the plane with dish soap/sponge to remove the white residue before waxing.


Evapo-Rust leaves a grey residue. Like the oxalic acid, this is not difficult to remove.


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## johnep (Apr 12, 2007)

WE used Rhubarb leaves with some success during the war.
johnep


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