How to fire harden wood ? (for spears, pila, etc...)

[Theodosius the Great]

Avete,

Does anyone know how to harden wood using fire ?
I read that the outer layer is slightly burnt but the rest of the wood is strengthened in the process.

I'm not sure if the Romans fire hardened wood when erecting palisades or constructing spears and pila.
But I'm assembling a weighted plumbata and am not confident the wood isn't going to snap the instant I withdraw
the weapon from my shield. So, I'm hoping I can strenghthen the wood via fire or some other method.

Thanks in advance for any helpful information.

~Theo

[Astiryu1]

I am not sure of actual techniques but I have played around with making staves for martial arts training and fire hardening. This is what seems to work for me:

From the tree-
Step 1- select and/or cut wood
Step 2- dry (at least a week)
Step 3- start a charcoal fire; let burn down to coals
Step 4- rotate the shaft on top of the coals until slightly blackened
Step 5- repeat process until satisfied
Step 6- Sand the shaft and treat with an oil for water resistance
Step 7- Start swinging!

*One tip the shaft should not catch fire!

I think the carbon from the coals has something to do with it as well as the heat. I would like to see a scientific explanation all I know is "It Works".

[Dithrambus]

A Google search produced several answers including this one:

http://www.ehow.co.uk/how_6558051_fire-harden-wood.html

Hope that helps

[Matthew Amt]

I haven't heard of any archeological evidence for the shafts of spears or javelins being fire-hardened, except maybe very primitive weapons that have no metal point. Regular wood seems to have worked for the ancients! If you are worried that your plumbata will break even before you throw it, you might have too thin a shaft, or maybe you're underestimating the strength of the wood! Ash is tough stuff. I'd say finish it up unhardened and see how it goes. (Easy for me to say, eh?)

Good luck and Vale,

Matthew

[Astiryu1]

In one of the translations of "The Battle of Maldon (991 a.d.)" I remember something about fire hardened spears. I am unsure of how accurate that may be though. I forget the place where I read it even; so please take this with a grain of salt. :?
In a hasty levy situation the soldiers "might" have to use fire hardening to quickly make spears ready for battle if newly cut from trees or something.

[Theodosius the Great]

Avete,

Thanks for the information everyone. So far it seems few reenactors have experience with fire hardening techniques.

*One tip the shaft should not catch fire!

That's exactly why I asked for people who have experience to comment since I prefer the safest way to execute the
process in a home setting.

Actually, I think after the hardening process the wood becomes fire resistant since the outer skin is already burnt.
If true I would think the Romans must have used this method in constructing palisades. Otherwise barbarians could
simply set them on fire from afar with impunity.

If you are worried that your plumbata will break even before you throw it, you might have too thin a shaft, or maybe you're underestimating the strength of the wood!

The latter is likelier. I had to shave down the end so it would insert into the head. Yeah, I should use ash instead of the cheap wood from the hobby shop.
Thanks, Matt. Great advice as usual.

~Theo

[Matthew Amt]

Actually, I think after the hardening process the wood becomes fire resistant since the outer skin is already burnt.
If true I would think the Romans must have used this method in constructing palisades. Otherwise barbarians could
simply set them on fire from afar with impunity.

People all over the planet built wooden palisades, but I've never heard anything about fire-treating the wood. I really doubt that the enemy "could simply set them on fire from afar with impunity"--a few fire arrows are not going to do it. Take a nice chunk of firewood, 4 to 6 inches thick, stick an arrow in it, wrap a bit of cloth around the arrow, and light it up. The log will probably not burn. You can try shooting burning arrows at it (or just at the neighbor's fence, ha!), if you want to burn your hand, your bow, your feet, your lawn, etc... Now do the same thing against damp mossy logs at the top of a steep embankment, while other people throw buckets of water at the flames (and bricks at your head). You need to launch an all-out assault, piling LOTS of kindling and combustibles against the palisade, and keeping the defenders down with missile fire, then wait an hour or so for the fire to burn enough wood to make a gap. Then charge through the hot coals... Granted, this would all be *somewhat* easier given a Roman marching camp fortified with those portable double-ended pointy stakes, but in that case you have to contend with Romans swarming out the gates and hitting both your flanks while you try to get the fire going! And again, several hundred of those stakes have been found, and no one has mentioned any trace of fire-hardening.

Don't get me wrong, I'm a dedicated pyromaniac! Wooden fortifications were definitely known to be flammable. But if it were "easy" to burn them down, they'd never have been used at all.

If you are worried that your plumbata will break even before you throw it, you might have too thin a shaft, or maybe you're underestimating the strength of the wood!

The latter is likelier. I had to shave down the end so it would insert into the head. Yeah, I should use ash instead of the cheap wood from the hobby shop.
Thanks, Matt. Great advice as usual.

Happy to help! Yeah, typical commercial dowels might be birch or something else, but won't be as good as ash.

In a hasty levy situation the soldiers "might" have to use fire hardening to quickly make spears ready for battle if newly cut from trees or something.

Hmm, I'm not sure what sort of situation you are thinking of. Levies were generally of men who were qualified for military service, and either had their own weapons already, or would be issued weapons from local or state-owned stocks. I've never heard of anyone frantically gathering unarmed men and telling them to cut sticks to fight with--they'd be slaughtered! The only reference that I remember to fire-hardened wood in Roman times is a mention (in Tacitus?) of certain German tribesmen who carried wooden javelins along with their iron-headed framea (short throwing spear). There was no implication of this being a hasty stop-gap, rather it was just a cheap way to get a few missiles in the air, in a culture which had very little in the way of metal weapons, much less armor. (Good grief, here I am shredding you again, Craig! I don't mean to, honest! I just seem to react to some assumptions that don't jive with what I've learned. Nothing personal!!)

Valete,

Matthew

[Gaius Julius Caesar]

Fire hardening is used to achieve a hardened point on a spear, as opposed to hardening the whole shaft.
when you scrape off the charred part, it naturally goes to a point, with a few reapplications.
Probably useful for setting up the fortification traps too.

[Astiryu1]

Hmm, I'm not sure what sort of situation you are thinking of. Levies were generally of men who were qualified for military service, and either had their own weapons already, or would be issued weapons from local or state-owned stocks. I've never heard of anyone frantically gathering unarmed men and telling them to cut sticks to fight with--they'd be slaughtered! The only reference that I remember to fire-hardened wood in Roman times is a mention (in Tacitus?) of certain German tribesmen who carried wooden javelins along with their iron-headed framea (short throwing spear). There was no implication of this being a hasty stop-gap, rather it was just a cheap way to get a few missiles in the air, in a culture which had very little in the way of metal weapons, much less armor. (Good grief, here I am shredding you again, Craig! I don't mean to, honest! I just seem to react to some assumptions that don't jive with what I've learned. Nothing personal!!)

Valete,

Matthew

You're just proving a point that is understandable! I posed it as a theory regardless. By "hasty levy situation" I would think an invasion or large ambush like the Teutoborg Forest. You would obviously have your equipped and trained soldiers but to fill out the ranks and rapidly get some numbers this technique could apply. Too many people volunteer but not enough weaponry to go around. This happened in WW2 in Russia (AFAIK) with issuing a rifle to one man and the rounds to another for lack of supplies (Leningrad I think). The javelins that Tacitus speaks of do you have the paragraph or whatever that contains them? I don't have Tacitus yet but am very interested in this particular part. I have used the fire hardening technique to make a couple of Javelins even carving a rudimentary blade out of the shaft and was fairly impressed by the performance (and the price)!

[Matthew Amt]

You're just proving a point that is understandable! I posed it as a theory regardless.

Cool, thanks. I'll keep shredding, then, bwahaha!

By "hasty levy situation" I would think an invasion or large ambush like the Teutoborg Forest. You would obviously have your equipped and trained soldiers but to fill out the ranks and rapidly get some numbers this technique could apply. Too many people volunteer but not enough weaponry to go around.

Okay, gotcha. Yes, there are a few times when emergency forces were raised, and I believe there is even a statement that special units of freed slaves in 9 AD were not given the usual armament. But lacking any elaboration on that rather tantalizing statement, I still think it's too much of a stretch to theorize hardened wood spears. We know the ancients were capable of producing amazing amounts of weaponry in a very short time if necessary, and there were probably already some stocks around.

This happened in WW2 in Russia (AFAIK) with issuing a rifle to one man and the rounds to another for lack of supplies (Leningrad I think).

Oh, yes, I remember that! Russians, geez, I'm not sure they count... In this case they were not only expecting at least 50 percent losses, they were basically *counting* on it! Not exactly standard Western doctrine...

The javelins that Tacitus speaks of do you have the paragraph or whatever that contains them?

Sorry, I don't have the citation offhand. Mostly I remember it from John Warry's little reconstruction in "Warfare in the Classical World", showing a hirsute young German in a breechclout and his handful of pointy sticks.

Matthew

[Theodosius the Great]

People all over the planet built wooden palisades, but I've never heard anything about fire-treating the wood. I really doubt that the enemy "could simply set them on fire from afar with impunity"--a few fire arrows are not going to do it.

Could it really be that difficult ? Siege towers were usually protected using animal hides or metal plates despite the fact the Romans were there on the spot to put out any fires.

I suppose the weather would be the greatest factor. The Roman burned through the improvised wooden wall at Masada (nothing damp about that place !) But I had the Antonine Wall more in mind. Setting a battering ram on fire might do the trick (maybe I've seen Braveheart too many times!). It must've been difficult for the Romans watch and protect every meter of the palisade wall (some 60 miles long ?).

In retrospect, it does seem impractical to fire-harden every log of a palisade even if only the outer logs were so treated. For that matter, I wonder if it would even be possible to fire-harden something a large as a single log. The process is a delicate one. There were probably easier ways to treat the wood against fire, perhaps coating it in beeswax for example ?

try shooting burning arrows at it (or just at the neighbor's fence, ha!)

:lol: Hmm...well, their house has been unoccupied for quite a while now... :twisted:

Happy to help! Yeah, typical commercial dowels might be birch or something else, but won't be as good as ash.

I'll check your famous suppliers page for a source

~Theo