Has any of you done any fire hardening of wood so that it would last longer as the implement you designed it to be (shovel, knife, spear, hammer, boat paddle.)?

I understand it involves heating wood to just below the charring state and then scraping it down with a not too sharp scraper (steel, rock, bone). I am not sure, but I seem to recall reading that this procedure had to be done to the item several times, and such wood hardened to a point would supposedly penetrate wood of the same type deeper than if it was just sharpened and used without fire hardening.

As I recall, they recommended the use of hardwood for this procedure.

Have any of you ever tried it and is it worth the effort?

Bountyhunter

Bountyhunter,

Sure, my kids and I have done that many times. Actually, the way I taught then to do it was as if they had no knife. Stick the end of the spear in a fire. As it chars, remove from the fire and scrape the char off with a shard of a broken rock. Continue, and a point forms - the very tip burns faster than the shank. Eventually, a graceful but not--very-sharp fire hardened point emerges - time varies with species of wood. If you are making a digging stick, you're finished. If you want a pointier skewer, grind it on a large rock (easiest) or use a rock in your hand to grind it. All very simple.

Different species of wood give different results. Fiddle around with it - it's a purposely fun thing to do whilst sitting around an open fire. My kids have been doing that since they were 3-4 years old and they still get a kick out if it once in a while.

HTH,

Tom

AyersTG:

I know the pointed stick part is very easy, but have you or do you know of anyone that has tried it on broad application like a wooden shovel, or a boat paddle.

I know for an impact tool, the root systems of trees are better and last longer than the wood above ground for the same purpose (Got that from watching old style woodworking with Roy Underhill on PBS.), but was wondering if short term impact tool would benefit from fire hardening as working above ground wood is easier than getting and working roots?

Thanks for the feedback.

Bountyhunter

Funny this should come up I just posted on this subject on a couple of other boards not long ago.

Fire Hardening

As a foolish youth I read in books of outdoor lore about fire hardening spear points. Most just left it at that mention. A few such authors even talked about charring the wood and very little else. With typical youthful enthusiasm I thought that would be neat and tried it. Yeah Right. Results were very disappointing to say the least.

First such treatment burnt the point off. The charred wood was even softer than the green wood started out. Even after scraping the char off the tip was still softer. A real big time bummer. Which is a very good reason to try things out before depending upon them.

Well a few years ago I heard a little different story on how fire hardening actually works. Experimenting time again.

SUCCESS! It really works. Now don’t get me wrong this technique does not make a point in soft wood or even hard wood that is stronger than steel or sharper than a flint point. But it is better than a carved wooden point alone. This process only works on green wood not dead dry wood.

What it does is boils the water that is in the sap. This does 2 things. It dries the wood that toughens it to start. It also crystallizes the minerals that were in the sap forming almost a varnish that increases the hardness of the point.

The trick of doing this is you bake rather than burn the wood. Instead of putting the point into the fire you slowly rotate it above the coals. The final appearance it like a well-roasted turkey. Golden brown not black it takes time so don’t rush it If it starts to turn black it is starting to char. Stop before it is ruined. Trying to speed things up by plunging it into the fire will result in a wasted mess.

Hopefully this will save some others from falling into the same misconceptions I labored under for years.

That makes sense, but I'd like to point out one thing:

Charring green hardwood and scraping away the char works fine for forming a hardened point - in fact, the whole reason I taught my kids that was to make a point in a robust stave when they were too little to manage that carving with an age-appropriate blade and their musculature at the time. I have no experience with what would happen if the point was carved and then charred, but I expect that it would result in a more parabolic tip rather than a sharp one - maybe even blunter than what results from starting off "square". See my earlier post - that's what our experiences have been.

I'm sure that what you wrote is right-on the money w.r.t. a pre-carved point. And to reply to Pete's last post, no I have not tried this with flat forms. I suppose that a freshly carved blade from green wood would respond to what you wrote, although I wonder about warping.

Oh - one other charring experience I can relate - carving a spoon or bowl from green wood by using the char-and-scrape method DOES result in a more durable artifact as well, in my experience.

For what it's worth...

Tom

Raspy & Ayers GT:

Thanks for the details!

I am going to have to try it in all ways (charred, uncharred, preformed, & formed after charring.)

Up to this point, I had always thought that dead dry wood was the way to do this, but now I see why this system works because of the chemical reaction of the sap.

Thanks again!

Bountyhunter