Primitive Archer
Main Discussion Area => Bows => Topic started by: islandpiper on November 02, 2008, 10:29:27 pm
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To the Mods: If microwave questions don't apply, then boot this one.
OK.........how about if a fellow had a spare used microwave, and made a hole in the left side just big enough to slide in a well-soaked limb-end, and sealed up the space around it with tinfoil. Then, closed the door and hit START. That wood would be heated inside and out, no scorching, ready to pull out and stick in the bending press.
Hmmmmm...............
comments? I'll duck if I see old boots or 'maters headed this way.
piper
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Wouldn't there be a reaction with the tin foil?
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huh!!
well my understanding, and i may be way off base,is that a microwave COOKS from the inside out. if this is true then how would you know
if you havent cooked out all of the moisture from the interior of the wood before the outside became hot enough.
me personnaly would be afraid to try and bend it at this point then,wood even when hot still needs to have moisture in it to be pliable.ifn it gets to dry it becomes
brittle and thats when you here thise dreaded cracks and snapping sounds that we all fear.
but what the hell give it a try and let us know
peace,
tim
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OK, use a wet paper towel. you just don't want the waves to escape . Remember, the walls of the oven cavity are metal, too. the reason foil reacts in the oven is that it is not a part of the circuit. Mashing it into a hole in the wall would make it so.
I'm pretty sure that there would be no trouble as LONG AS THE HOLE WAS FILLED with something that will reflect or absorb the waves.
piper
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I have heated smaller pieces of wood in the micro for bending with no trouble. The only change here would be the insertion of a limb into the side of the oven. piper
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I think it would work....Just plug the Hole with some Plumbers Putty....and make sure that you don't overexpose it..only one sure way to figure it out.....give it a Shot!! And let Us see and tell Us about the Outcome....I for one am interested..........
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OK, I'll start looking for one of those pre-Columbian wood-burning microwaves. piper
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An experiment was done at MoJam a few years ago with a microwave for bending wood. I think it was successful. There may have been an article in PA about it. ??? Pat
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I'd be careful playing around with a microwave... those things are designed to be perfect waveguides for standing microwaves (entire graduate physics books are devoted to waveguides, just to give you an idea of complexity). The box isn't just a metal box, in other words. Plugging it with tin foil would probably just do the same as sticking tin foil in it and turning it on, though not as quickly. You'd be better off plugging it with rubber or some type of microwave safe plastic, though that'd do little to stop them. Keep in mind that practically anything metal or with water in it will get extremely hot. You could use one for bending small pieces of wood or drying them without modification, I've done both myself, but I would not reccomend trying to modify it. If you do, though, don't stand in front of it.
Oh yeah, and they do not cook from the inside out, they cook from the outside in like everything else.
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Pats right there was an article in PA about using a microwave to heat wood for bending. The author put a
hole in the front and back so anysection of the bow could be heated. It works but like any other method there
advantages and disadvantages.
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Yeah, I remember reading that article. I think I'll stick to regular heat sources.:)
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(yep, that stirred up the troops. Gave y'all something to think about besides the election)
Piper
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I know a guy whos done it, but I'm not going to try it anytime soon. Sounds kinda dangerous.
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Howdy Group,
As WaterLogged had mentioned, microwaves are complex.
And, the microwaves in microwave ovens are designed to excite water molecules in the food (or wood) placed inside the oven.
People are made mostly of water.
Microwave safe plastic, does it block microwaves or allow the microwave to pass through unaffected?
Aluminum foil, does it block ALL or some of the microwaves?
The idea of heating small wood pieces to bend (or heat treat) sounds interesting, but Modifying a microwave oven, by cutting a hole in it, is DANGEROUS!!
DON'T DO IT!!
Canoe
(Yes, I took plenty of physics course while in college.)
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Canoe -
Microwave safe plastic I would guess blocks some of the waves, and aluminum foil blocks pretty much all of it... and turns it directly into heat. This heat will first cause flaming pieces of the metal to fly off (sparks) but a little while later will cause it to rapidly oxidize (burn) and turn into a light gray powder.
As to it effecting the human body.... as canoe said, it excites the molecules, which basically means it heats them up. This is ok for a bit with the human body, but if you get a molecule excited next to DNA... that could cause cancer. Probably won't, and you'd probably need to use the thing several times, standing in front of it, to even have much of a chance of getting it, but still not something that you'd want to mess with.
As a side note: adding metal into the box in any way changes the fundamental frequency of the box, and could overload the magnetron that makes the microwaves. In other words, slowly break it.
A microwave works really well for bending smaller pieces of wood, like the recurves for a horn bow, if you stick the wood you want to bend in a cup full of water, and stick it in the microwave for a while, watching it close, and let it boil for a bit. Works great. If you could find a microwave big enough to do a shortbow, that'd be cool. Modifying one, not so much.
Waterlogged (year away from a physics degree)
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that sounds like an idea there. have you tried it yet?