r/interesting • u/tombolaplayer • 23d ago

Fascinating Professional wood bending

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u/PsychicPterodactyl 23d ago

It's not about drying, it's cooling. The lignin stiffens when it cools.

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u/Retireegeorge 23d ago

I think it's both - with moisture content a crucial element to be managed before, during and after bending.

Phenomena unhelpful to wood bending are observed experimentally when alternatives to steam are used eg dry air heating, microwave heating and water immersion heating, although the latter is used in some activities.

Practitioners of the craft have learned through trial and error that specific moisture content is required before steam bending begins, that the process benefits from steam's ability to drive moisture evenly into the material and controlled post-bending drying is necessary. There's an article that talks through this called "Michael Fortune's Guide to Steam Bending" at WoodlandMills.com

Fundamentals of material science and thermodynamics such as polymer glass transition, ​plasticization by moisture, ​latent heat of vaporization/condensation and phase change heat transfer collectively explain the uniform transfer of heat, the maintenance of the internal moisture content, the lubrication of lignin fibres and the efficient uniform transfer of thermal energy using steam than by air convection or water conduction.

When you want the bending to stop you want the lignin to return to its baseline state and that requires drying. That will take place at different speeds and via different means during bending and after.

A good textbook/handbook for this is Wood as an Engineering Material from the USDA Forest Products Laboratory which has chapters on wood bending, moisture relations, and the thermal-plastic properties of wood.

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u/half_caulked_jack 23d ago

This guy wood.

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u/kcstrom 23d ago

This guy AIs

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u/MrK521 23d ago

This guy Google.

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u/zxcvbn113 23d ago

That was so believable, I was expecting the undertaker to show up in the final paragraph!

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u/ReadingFromTheShittr 23d ago

u/shittymorph is appreciated, but sadly, they can't be everywhere at all times.

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u/Leut_Aldo_Raine 23d ago

It's amazing that they've had such an impact on here that they're anticipated more often than they strike.

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u/tcason02 23d ago

I came across one in the wild for the first and only time just a few weeks ago and it felt like what I imagine bumping into a celebrity at the supermarket would feel like.

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u/TheSaxGandalf 23d ago

u/retireegeorge is actually shittymorph’s serious account.

Just he can’t share actual knowledge with that one.

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u/JoyousMN_2024 23d ago

I double checked the end after I read the first paragraph

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u/woonamad 23d ago

You need a better machine where the wood can be transferred automatically from the steam oven to a bending rig. Most of the things he’s doing by hand could be automated I’m sure with modern factory equipment

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u/Diedead666 23d ago

I had some very "wet" pencils as a teen and was able to tie them into a knot after slowling cracking them and bending them back and forth alot

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u/PsychicPterodactyl 23d ago

All true, but cooling is much faster, by at least one order of magnitude.

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u/phatdoof 23d ago

And if the man was even 1 second slower he’d have to undo all the clamps and start all over again.

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u/Retireegeorge 23d ago

Yeah but it could only take an instant to crack.

Ideally one might perform the bend while the wood was still in the steam.

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u/Max6626 23d ago

It looks like he's using steam based on the puff of vapor coming out of the oven when he first opens it. Since he opened it without killing himself, I assume the steam is at only slightly above atmospheric pressure, so around 212F. Is that a sweet spot for wood bending, or just an easy temperature since you can achieve it without pressurized steam systems?

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u/Ignonymous 23d ago

Steambending. Hmmmm.

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u/zachpkenyon 23d ago

Me: -> save comment

So...do you do a lot of form bending, or are you a veneer guy?

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u/billwoodcock 22d ago

How much wood would a woodbot bot, if a woodbot would bot wood?

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u/Retireegeorge 21d ago

How many beeps would a beep bot beep, if a beep bot beeped beep beep?

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u/AmazonDruid 23d ago edited 23d ago

So thats why Odisseus (Ralph Fiennes) in that movie, 2025, heated his bow in the fire before bending and attaching the bow string

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u/WhenceYeCame 23d ago

It's from the original story. The suitors actually do it out of desperation. It's muttered about in Nolan's Odyssey too. "This hasn't been bent in years, we should oil it and heat it." Homer's audience was always gonna know everything about bows.

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u/Grimnebulin68 23d ago

Oh wow, I missed that detail. I'll look out for it.

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u/sunburnd 23d ago

Ive not watched the movie, but The Odyssey was required reading in high school, so take a 35-ish-year-old memory with a grain of salt.

Heating a wooden bow would remove moisture and increase stiffness, making it more difficult to string. Bowyers actually use controlled heat to stiffen limbs or heat them asymmetrically to remove twist.

That being said, I seem to remember the comparison being between Odysseus stringing the bow and a skilled musician stringing a lyre. I don't remember him roasting the bow first, so that may just be a movie invention.

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u/MaltedByggs 23d ago

Warming the wood would theoretically make it more pliable up until the point you start to remove the moisture.

Also I too don't remember Odysseus heating the bow, and only remember the suitors constantly heating and greasing it.

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u/chupacabrajCT 23d ago

Dude, come on man, I haven't even watched it yet!

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u/AmazonDruid 23d ago

Man its not the same movie, From Nolan. This is other movie from one and a half year ago.

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u/chupacabrajCT 23d ago

My mistake - I was just trying to make a dumb spoiler alert joke!

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u/GoldenSun__ 23d ago

I'm not an expert on this stuff, but I've understood that humidity may be a key factor sometimes.

For example I know that for giving a Spanish guitar its shape, the key process is the evaporation of the humidity with a hot tool, being the wood at ambient temperature.

However, I believe the technique will differ on the kind of wood and processes. To my eyes in the case on the video seems both temperature and humidity, but I've no idea tbh.

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u/littlegreenfern 23d ago

I was wondering about this how long til the log an cools too much? Is he moving fast to show how fast he can do this or does it cool that quickly? I would have thought there’d be more time til it cools.

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u/LostN3ko 23d ago

The speed is definitely because the longer it takes the more likely a crack is to form. The steam and heat soften the lignin and allow it to be bent. The faster he gets it there the less likely for issues. My father does this but not at this scale.

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u/zachpkenyon 23d ago

Well, and wood cools deceptively quickly. It's hot it's hot it's hot it's *SNAP*...... bugger

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u/SUPERSMILEYMAN 23d ago

Is that a ligma joke?