Returning Rust Spots on Handplanes

[Mark R Webster]

Lately I have been lapping some old hand planes to flatten them. A few had some significant rust and pitting which I treated with Evaporust and then lapped the bottoms flat and to bear metal. While the rust and pitting appears to be gone, you can see still see “shadow marks” where the rust was. (I suppose the shadows could be rust deep in the metal) In just a few hours these shadow areas darken and become unsightly. What can I do to stop this from happening. I have tried several rust preventative materials which slow the return of the discoloration but want stop it from happening. I want to end up with a “clean” unspotted/unmarred look of the freshly lapped surfaces allowing the surface to darken evenly and develop an even patina over time. I don’t want to apply a coating that would create a clear paint like surface. I am looking for something that will soak into the metal, neutralize whatever the discoloration is, and then protect the metal from further rust. I don’t want to go to something like bluing. Any suggestions. Do I just need to lap until the discoloration is absolutely gone? We are talking some serious lapping if that is the case and I don’t want to sacrifice any more metal than necessary. Thanks.

[peter Joseph]

Paste wax or camelia oil are going to be your best bet. Neither will create a "paint-like" surface and should do the trick. Other than that I'd work on just living with these imperfections. The #6 I use with my shooting board always has a stain from where I position my thumb. You could of course purchase contemporary planes and maintain them in pristine condition if it bothers you that much.
Peter

[Steven Harrison]

I use Evaporust and usually a little sanding gets rid of the darker spots. I also use a metal polish though and then wax. I haven't noticed anything like you're describing.

[Mark R Webster]

Thanks Peter and Steven

[Dave Parkis]

Evaporust will stain the metal. I scrub planes with a 3M Scotch-brite pad. Specifically, the brown/grey ones to remove the stains you're describing. After that I wipe them down with Camilla oil and don't have any problems.

[Jim Koepke]

I am looking for something that will soak into the metal, neutralize whatever the discoloration is, and then protect the metal from further rust. I don’t want to go to something like bluing.

My knowledge on bluing is minimal. You might give it a try as it is basically a form of oxidation of the metal but from my understanding of the process it also stops further oxidation.

Also from my recollection is there are different types of bluing that produce blue, brown or a black patina on the metal.

FWIW, some of my planes have a nice natural patina, some look like they were found in a creek bed. To me it is a pleasure to have a nice looking plane, but in the end it is the work the plane does as it won't earn a place in my shop on its looks.

jtk

[Mark R Webster]

Thanks Dave... Well said Jim...

[steven c newman]

Maybe something like Paul Sellers uses? A small can, with a rag stuffed inside, kept soaked in a light oil ( I use 3in1) he does a quick swipe on the tool before he puts them away.

[Mark R Webster]

Thanks Steven

[Stanley Covington]

There are remnants of salts in the metal. Nasty, stubborn, pervasive stuff.

Strip the plane to its components. Plug screw holes with wooden plugs or modeling clay. Coat areas you want to keep dry with clear lacquer.

Scrub the clean metal with a scotchbright pad, baking soda, washing soda, or borax (to adjust PH), and very hot distilled water (tapwater always contains chlorine) to neutralize and clean. You need to get the steel very hot and very wet. Rinse and scrub well with hot distilled water to remove baking soda, etc.

While still hot, wipe the metal dry, and immediately wet sand (400~600 grit W/D sandpaper) with WD-40, CRC 3-36 or other chemical that displaces moisture. After an hour, clean off the chemical and reapply. All the salts and water should now be gone.

Don't use WD-40 for long-term corrosion protection since it quickly evaporates without leaving a protective film.

If you intend to blue the metal (I don't think you mentioned that in your post, but others seem to have interpreted it that way) then do not apply any chemicals, but go straight into degreasing & bluing. Ditto if you intend to paint.

[Mark R Webster]

Interesting I will give the procedure a try. Regarding salts, can you elaborate what salts these might be, or point me to more resources on the subject? I am afraid I am lacking in the science of it all
So if I am understanding correctly, after scrubbing with scotchbrite, heating and treating with washing soda changes the ph which somehow brings the "salts" to the surface which are then sanded off with wet/dry paper using CRC 3-36 as a lubricant and to displace moisture. Is that correct? Thanks Stanley!
Mark

[Stanley Covington]

Interesting I will give the procedure a try. Regarding salts, can you elaborate what salts these might be, or point me to more resources on the subject? I am afraid I am lacking in the science of it all
So if I am understanding correctly, after scrubbing with scotchbrite, heating and treating with washing soda changes the ph which somehow brings the "salts" to the surface which are then sanded off with wet/dry paper using CRC 3-36 as a lubricant and to displace moisture. Is that correct? Thanks Stanley!
Mark

By salts, I mean the various incarnations of NaCl and CaCl. Some possible sources are environmental (saltwater spray, dust, airborne). Salt is as problem in coastal areas of course. But environmental salt is also a real problem in areas that salt the roads and use salt removal chemicals on sidewalks and driveways. Human sweat contains salt.

Salt attaches itself to iron, much more strongly than plain H20, and is hard to get rid of. There are chemicals made for the marine industry specifically for removing salt. But with heat, pure water, agitation, and adjusted PH, you can get rid of it. The process will break the bonds of the salt with the iron and float it away.

I emailed a blue-water sailor friend and he recommended washing with vinegar in addition to the soda scrub. According to him, the acid helps to neutralize the salt.

If you leave the metal bare after this process, it will oxidize. The sanding/oiling process removes water from the metal's ins and outs, and seals it. You don't want to put plain oil over metal with water in the pores, especially if it might contain salt. Paint is better than spray chemicals for protection, but won't work on the soles and sides of iron plain bodies, of course.

[Mark R Webster]

Very informative and helpful Stanley thanks!!

[Roy Turbett]

Try soaking in white vinegar for no more than two hours and thoroughly rinse with water and washing soda to neutralize the acid. Then oil and wax.

[Mark R Webster]

Thanks Roy!