Tool Maintenance: Corrosion Prevention

“How dull it is to pause, to make an end,
To rust unburnish’d, not to shine in use!
As tho’ to breathe were life!”

Alfred Lord Tennyson, Ulysses

Between damaged tools and guns, corrosion prevention has been a high priority for your humble servant over the years motivating me to purchase many corrosion-prevention products and test them in various climates. After scaling mountains of hype and fording floods of BS I think at last I have something of value, perhaps even the genuine article, to share with Gentle Readers.

While by no means comprehensive, in this article your humble servant will address three common causes of corrosion in steel woodworking tools, as well as some methods of prevention. The three causes are: Corrosion due to sharpening, corrosion due to handling, and corrosion due to storage.

But first, to help Gentle Reader understand the basis for the measures I will recommend below, allow me to explain my sharpening philosophy.

Tool Philosophy

The word “philosophy” is of Greek origin and means the “love of wisdom.” I won’t flatter myself that I developed any original wisdom about maintaining tools, because the truth is I stole most of what I know from better men and the rest came ipso facto from my own screw-ups. Shame is the best teacher.

Professional craftsmen have no choice but to constantly maintain and repair the tools of their trade, but necessary or no, clients and employers often resent the time the craftsmen they hire spend maintaining tools during the work day. After all, they are paying them to make a product, not to fiddle with tools, at least that’s how most Clients look at it. The perceptive craftsman will strive to understand his Client’s perspective if he wants to be trusted with profitable repeat work.

Therefore, I don’t sharpen, fettle, or repair my tools at the jobsite anymore than is absolutely necessary, and never in front of the Client or employer. This is not some feel-good yuppy-zen BS, but a serious, concrete work philosophy with physical and financial consequences. It was taught to me by experienced craftsmen in America and Japan, all since retired to the big lumberyard in the sky, who knew what they were about. It has served me well.

So how do I keep working when blades dull, planes stop shaving, power tools stop spinning and bits stop biting? The most reliable solution is to have multiple saws, planes and chisels in the types/sizes critical for that day’s work, and even extra bits and power tools on-hand whenever possible, so that if a particular chisel or plane becomes too dull to get the job done, or a bit breaks, or a circular saw, for instance, goes tits-up, I need only pause work long enough to retrieve a sharp, ready to rock-n-roll replacement from my toolbox or tool bag.

This means I must purchase, sharpen, fettle and carry around more tools than I am likely to use during that workday. But since I don’t carry my tools in my “pocketses”, and they are partners that earn their keep, I do not consider it wasted money. In fact, this philosophy has resulted in tool-maintenance habits that I believe ultimately save me time and money while improving my work efficiency all while reinforcing my Client’s or employer’s confidence in me, just as the old boys I try to emulate said they would.

Of course, after a few days of continuous work I will have accumulated multiple blades that need sharpening, so if I am to keep making sawdust I must sharpen them in batches of 5~10 at a time. And because I sharpen in batches, as do professional sharpeners, I have given great thought over the years to maximizing positive results such as speed, sharpness achieved, and economical use of stones while minimizing negative results such as rusted steel. I humbly encourage Gentle Readers to give these matters just a few seconds of consideration. What have you got to lose besides steel?

Corrosion Prevention: Wet Sharpening

The corrosion risk to tools when sharpening is caused by residual water in the scratches, cracks and crevices of the blade, as well as accumulated chlorine from tap water, promoting rust, especially at the very thin cutting edge. Yes, that’s right, I’m more worried about corrosion dulling the cutting edge than of it creating unsightly red spots elsewhere on the blade.

When sharpening a batch of blades in my workshop, after a blade is done on the final finish stone, I dry it with a clean paper towel, apply a few drops of Corrosion Block, smear it around on the blade to ensure a complete coating, and set it aside to draw water out of the pores and seal the steel. It works.

Corrosion-X is another good, but stinkier, product. Neither is good enough long-term, however.

After the blades have sat for a while, usually at the conclusion of the batch, I wipe off the CB and apply CRC 3-36. This is a paraffin-based corrosion preventative that floats out water. Paraffin won’t evaporate or wick-off and is the best product I have found to prevent rust developing on a clean, moisture-free surface.

CRC 3-36 sprays on easily and soaks into everything, and if allowed to dry, will give good long-term protection, as in years. It’s especially good for saw blades because it gets deep into the teeth. But you don’t want to apply it to anything even a little wet with water because paraffin may seal it in promoting rust. Ergo, Corrosion Block first.

There are many rust-prevention products on the market, so I am not suggesting CRC3-36 is the best, only the one I prefer, partly because The Mistress of the Blue Horizons doesn’t object to the smell too strongly if it wafts into her holy chambers from the workshop. If I use Corrosion-X, however, she bars the door with her trusty broom, bayonet fixed and leveled at my genital area, and makes me strip off my stinky clothes before she’ll let me back into the house. My love is a gentle flower! With sharp knives! But I digress.

This system works fine for short-term purposes, and even for long-term storage if I wrap the tool in newspaper or plastic to protect the coating.

When sharpening in the field, or if I will be using the tool right away, I don’t bother with spray products, but just strop the blade on a clean cloth or the palm of my hand to generate friction heat, apply some oil from my oilpot, and call it good.

If you don’t own and use an oilpot already I won’t call you an idiot, but I still remember the time long ago when that word was directed at me by someone I respected for not making and using one. He was right.

A useful trick I learned from professional sword sharpeners in Japan is to use chlorine-free, slightly alkaline water for sharpening. I mix Borax powder with distilled water in a plastic lab bottle to use to keep stones wet and to wash blades when sharpening. Washing soda works too. A little lye added to sharpening water will also increase its pH. Using such water will not entirely prevent corrosion, but it certainly slows it way down. Test it for yourself.

Corrosion Prevention: Handling

We sometimes pull out a chisel, saw, or plane blade to gaze upon it. They are lovely creatures, after all and welcome our adoration. There are two things to be aware of when doing this, however.

Recall that the adult human body is comprised of approximately 60% water, some of which is constantly leaking out of our skins mixed with oils and salts. When you touch bare steel with your hands, skin oils, sweat, and the salt contained in sweat stick to the steel and will cause rust. It’s only a matter of how quickly and deeply.

The solution is to avoid touching bare steel you will later store away with bare fingers, and if you do touch the blade, wipe it clean and apply some oil from your oilpot or spray can right away before returning it to storage.

Gentle Reader may be unaware, but there can be no doubt that harsh words not only hurt the tender feelings of quality tools, but can directly damage them. How do I know that rude language offends steel tools, you say? Well, I have ears don’t I? In addition, over the years I learned a thing or two from professional Japanese sword sharpeners and evaluators, who are even more obsessed with rust than your paranoid humble servant, no doubt because of the high financial and historical costs of corrosion in rare and expensive antique weapons.

With the gift to the entire world of the Wuhan Flu from Dr. Anthony Fauci (aka Mr. Science) and his Chinese research team, we have all become more aware of the human tendency to constantly spew droplets of bodily fluids, often containing nasty bugs, into the air around us sometimes with unpleasant consequences. A handsaw can’t catch the Wu-Fau Flu, but fine droplets may find their way to the steel surface when we talk to them or around them. Corrosion ensues.

In Japan it is considered rude to speak when holding a bare sword. Indeed, it is SOP to require viewers who will get close to a bare blade to grip a piece of clean paper between their teeth to confirm the mouth is indeed closed and not spewing droplets of spit onto the blade.

I am not exaggerating the cumulative long-term damage fingerprints and moisture droplets expelled from human mouths and noses cause to steel objects. Any museum curator can confirm.

How does this all apply to woodworking tools? If Gentle Reader takes a tool out of storage and either talks to it, or to humans around it, please wipe it clean, apply oil, and rewrap it unless you will be using it immediately. It’s the only polite thing to do.

Tools deserve respect. Perhaps I’m superstitious, but I’m convinced that if we avoid rudely smearing salty sweat or spraying globs of spittle that would cause our tools to turn red and go away, they in turn will be less inclined to cause us to leak red sticky stuff. Some tools are vindictive if offended, donchano, and many of them can bite.

Corrosion Prevention: Storage

The air on this earth contains dust and moisture. Dust often contains abrasive particles harder than steel as well as salts and other corrosive chemicals. We must keep these particles and chemicals away from our tools.

Air also contains moisture that, given access and a temperature differential, can condense on steel tool blades causing condensation rust.

Your humble servant discussed these matters in length in earlier articles about toolchests, but a critical criteria of proper storage is to prevent dust from landing on tools, and to prevent the tools from exposure to airborne moisture and temperature differentials. A closed, tightly sealed, clean container, cabinet, toolchest or toolbox is better for tool storage than pegboards or shelves.

If Gentle Reader does not already have such a tool container of some sort, I urge you to procure or make one.

Tool Rolls

Your humble servant owns and uses fabric tool rolls. They are handy for transporting tools such as chisels, files, rasps and saws to and from jobsites but they have limitations of which Gentle Reader should be aware.

The first problem with tool rolls is that they appear to protect the cutting edges of chisels and saws, but that is only wishful thinking because the delicate and dangerous cutting edges are only hidden behind a thin layer of cotton or nylon. Guess what happens if you drop a cloth tool roll of sharp chisels onto a concrete slab.

If you bump a tool roll of chisels against another tool, then brush your hand against the now exposed but hidden cutting edges while digging in your toolbox, red sticky stuff may get everywhere. Oh, the humanity! Will this wanton bloodshed never end!?

Do tool rolls protect tools against corrosion? No, in fact they can make it much worse because fibers in contact with steel, especially organic fibers such as cotton, can wick moisture to the steel producing corrosion. Please see the photos above.

Leather tool rolls can be especially bad in some cases because of residual tanning chemicals.

I’m not saying don’t use tool rolls, only to be aware of their limitations and use them wisely.

As mentioned above, I do use fabric tool rolls in the field. The trick to preventing rusted blades is to insulate them from the fabric, so I make little plastic liners from the hard but flexible plastic used for theft-proof retail product packaging that fit into the pockets. Just a strip of plastic cut wide enough to fit into the pocket tightly and folded in half. Besides preventing rusty blades (chisel crowns will still rust) these little liners make it much faster and easier to insert blades into the pockets without cutting the tool roll, and to keep the blades from cutting their way out of the tool roll once inserted. The price is right too.

Canvas tool wraps are convenient for transporting handsaws, but they too provide limited protection. I wrap my saw blades in thin polyethylene sheet foam to help protect the teeth, isolate the blade from direct contact with cotton fabric, and add some insulation.

If you need to use tool rolls for long-term storage, I recommend you clean the tools, coat them with a paraffin-based rust-prevention product, and wrap them full-length in plastic wrap before inserting them into the tool roll’s plastic-lined pockets.

If tools are faithful and profitable servants, indeed extensions of our hands and minds, don’t they deserve more from us while they are in our custody than a rusty, pitted, neglected ruin like the plane blade pictured above?

YMHOS

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