Posts tagged #oiling tool handles

Penetration, Saturation and Coating, 3 Main Factors in Oiling Wooden Axe and Tool Handles

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Over the years I keep evolving and refining my methods and understanding of the process of oiling tool handles.  Although it is painfully simple, the obvious is not always so obvious.  I've been soaking my handles pretty deeply with oil for a long time, but still have had something of a fixation on coating them with a protective coat.  Until, I realized that a well saturated handle is it's own finish, and more.

a Coating ona a handle is a barrier between the wood and the environment.  But does it achieve that goal well, and what is the goal anyway?  The goal is to protect the handle from environmental changes in moisture basically.  Moisture swells the wood, and when it leaves, the wood shrinks.  When wood shrinks, it is stressed and those stressed can lead to cracks.   For some reason cracks seem more likely to form if the wood swells and shrinks repeatedly.  If the wood swells within the eye of a tool, the wood compresses against the hard metal of the eye walls, becoming crushed.  When it shrinks on drying again, it many shrink smaller, than it was before it expanded.  That is why soaking the eye of a tool in water when it is loose will eventually make it even looser.  A good thick coating of cured linseed oil can help prevent the entry of moisture, and anytime oil is used on a handle, some of it soaks into the wood to some depth, bringing in the factor of penetration, which must help some.  A coating is basically still very thin though and will wear off over time.  These are handles remember,  They are essentially rubbed over and over again.  And although some penetration is always occurring, the questions to ask is how much good is penetration when it is shallow and of a low saturation.

Enter Saturation.  Saturation if you look it up, basically means full or at maximum capacity.  But it is commonly used with a quantifier or clarification like partially, mostly, completely.  If I soak a handle numerous times with linseed oil, it will penetrate to a certain depth, but unless it is applied regularly and in quantity, it will have a very low saturation as the oil spreads itself out deep into the wood structure.  Eventually, it either reaches the middle or some unknown depth and starts to increase it's saturation eventually filling the wood to the point that no more will soak in.  This 2 minute video shows the process I pretty much use now.  If you get tired of adding expensive oil to a handle, try stopping for a month to let the oil in the handle cure and penetration should slow down.  Some handles will take a lot of oil.  Fortunately, oil is light.

Now if we think about a handle that is fully saturated with oil, for even 1/8 of an inch deep, let alone more, we now have something like the equivalent of a 1/8 inch coating.  But even more cool, it is actually protecting the wood itself by filling the pores and structures that water would fill.  If you leave such a handle out in the weather, water droplets just bead up on it and sit there.  Not recommended, they aren't necessarily immune to moisture, but it's telling.

droplets on a well saturated knife handle.  Two hours later they were still there, though smaller, but I have little doubt that at least the majority of missing water left be way of evaporation and not penetration.  That is a test better done in high humidity, not on a warm breezy morning.  This handle has probably not been oiled since it was originally treated 2 or 3 years ago.  After all, the treatment cannot wear off.

droplets on a well saturated knife handle.  Two hours later they were still there, though smaller, but I have little doubt that at least the majority of missing water left be way of evaporation and not penetration.  That is a test better done in high humidity, not on a warm breezy morning.  This handle has probably not been oiled since it was originally treated 2 or 3 years ago.  After all, the treatment cannot wear off.

Try it on a handle and see what you think.  It is a long process and the oil is not always cheap.  many tools are also not subjected to much in the way of atmospheric changes, so it's not something we have to use everywhere.  I'm pretty sold on it though and any axe that I plan to keep and use gets the full treatment now.  Dudley cook recommends the same basically, but he maintains with an occasional coat, which I think is unnecessary if the wood on the outside of the handle is well saturated.  The wood essentially becomes it's own finish.  If the wood will ever take oil on and soak it up, do it, but it it doesn't, there is no need to keep coating it. 

I use food grade linseed oil (usually labeled as flax oil, which is the same thing) anymore and have found ways to pick it up cheap enough.  Boiled linseed oil is toxic and I think it probably dries too fast.  Prices change on amazon constantly, but this brand is usually about the cheapest, but do your own research.  I've also found flax oil at the local cheap food outlet where they send overstock and expiring stuff.  Other oils can be used as well, walnut, hemp, poppyseed and tung oil should be adequate, but I really haven't used any of them enough to say for sure.

For handles that you don't need to saturate, I recommend a thin coat of oil once or twice a year, or better, just whenever you have an oily linseed rag.  Raw linseed oil will cure, it just takes longer.  So called "boiled linseed oil" contains metallic driers and solvents that speed curing time.

I have more ideas and experiments brewing around this problem, and no doubt you'll hear more about it in the future.

My Simple Deep Penetrating Axe Handle Oiling System

It took my many years to finally arrive at a very simple but effective system for oiling axe handles.  I'm pleased to say that Author Dudley Cook came to the same conclusion and recommends pretty much the same as I do in The Axe Book.  This is the first of a series I hope to continue of super accessible bullet point videos called 2:00 Minute Technique.  The idea is to deliver very useful information in two minutes or less.  Of course being rather thorough most of the time, most subjects will be covered in more depth as well, but these will be quick start guides with enough information to get to work.  I'm also linking the long version of oiling tool handles where I talk about drying v.s. non drying oils and geeky stuff like that.

This system penetrates the handle deeply.  How deeply I don't know as I haven't sliced open a handle to find out yet, but it has to be pretty deep considering all the oil some handles are capable of sopping up.  It probably builds up especially a lot in the outer rind of the handle wood.  I think of it as replacing water that was once in the living tree.  As long as you use a good drying oil, like linseed, it will cure to a tough plastic like substance, the same stuff oil paints are made of.  I use raw oil because it has a slower curing time allowing for deeper penetration before the oil on the surface seals off the pores.  The other reason I use raw is because the product known as boiled linseed oil is not boiled linseed oil at all, but rather a compound containing solvents and toxic metals to the end of decreasing curing time.  I've actually gone now to using food grade flax oil only (same as linseed oil,  but food grade is usually called flax oil).  The last can of "pure raw linseed oil" I got smells of solvents, so I just found the cheapest flax oil I could on amazon and ordered that.

There is concern among some that raw linseed will never cure enough and will remain sticky.  I've been using it on my handles for a long time and it cures out plenty well.  Whether it will cure as hard and tough by comparison to boiled I'm not sure, but it's definitely more than adequate.  I can assure you of that.

I see "oil finish" recommended a lot, like Watco or Danish Oil Finish.  As far as I know, they are all cut with solvents and dry quickly.  If part of the liquid that soaks into your handle is solvent, then when that solvent evaporates it would seem that using these preparations would leave less total oil in your handle with each coat, penetrating or not.  Personally I avoid working with solvents because they give me heartburn every damn time.  Using food grade oil is great for me since I'm applying it over and over again all day, I can keep it in the house near the woodstove for faster curing and don't have to put on gloves or even wash my hands if I don't want to.  I usually just wipe off the excess oil and get on with my business.

Once the handle is thoroughly penetrated the oil will not soak in anymore.  If you get tired of putting oil on, or don't want to use so much oil, I think you could stop for a while and let the oil cure a bit before continuing.  Eventually, you can start to build up coats as a surface finish one thin layer at a time. Just apply the layers very thinnly and allow to cure to the touch before adding another.  Building up a surface finish is not a necessary step, but it looks nice and insures the handle is completely sealed.  I tend to just add a thin coat once or twice a year when I have an oily rag.  Polish comes with use.  There is probably a way to fake it by buffing etc.  I wouldn't know.  I'd feel like a dumbass sitting around trying to make my tools look like I use them when I could just be using a tool instead.

This system takes a lot of oil and a lot of time and may be overkill for some of your handles, but give it a try on something and I think you'll like it.  The knife handle below is deeply saturated and turned out awesome.  Repeated oilings took that porous, soft birch handle and made it into something altogether different.

And here is the long version.

Posted on December 20, 2016 and filed under axes.