Primitive Archer
Main Discussion Area => Bows => Topic started by: Jodocus on August 15, 2012, 01:26:17 pm
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Help, I need advice:
I was working on a maple (Acer platanoides) stave yesterday that I planned to make a flatbow from. I had steamed reflex into the tips about 3 month ago. Not too much, just some. about two inches of reflex on the last 4 inches to the tips. I wanted these to be working reflex.
I had done this when the stave was still about an inch thick. This might have been a mistake. Now that it is down to what it is, maybe 2/5", the reflex just pulled out in the tillering. not all of it, but almost. ??? :o :( >:( :-\
Now: I really want those tips to be flexed. Is it any point to re-bend them? I don't feel there is, but I coul imagine that by thinning it, I cut away all but the compressed part of the wood, this might be better this time that it is as thick as it will be.
I also read you can glue on a second layer of wood on the belly side? I'm far from proficient at woodworking and I use only hand tools, so the thought of cutting that glueline is a bit intimidating. Any good tutorials anywhere?
any other options?
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Wet wood pulls out, or you didnt leave the heat on it long enough. My guess is moisture.
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when i steam in recurves a nd such i like to put it back on the form and heat treat after it sit's a bit just for this reason, they stopped pulling out, Bub
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I second the heat treat after steaming. Also, if you want 2 inches of reflex, I'd steam in 3 or 4.
Gabe
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Thanks for the replies. I'll probably try the heat treating. I never have heat treated, but I've been planning to do so and wondering about it.
The wood may still be wet, PD, but it has been sitting 4 months in a roughed out state, so it's probably the dryest of all my wet pieces. Also, It had stopped loosing weight 2 months ago. I had really hoped it was dry enough by now.
So:
- I steam bend it again, ab bit more this time. When I'm done tillering.
- I let it sit a while (a couple of days? weeks?)
- I heat the belly where I bent it 'till it discolors, while I still sits in the jig.
- I let it sit a while again.
right?
I have no hot air gun yet, gonna get me one. Does it need finely adjustable temperature or does a simple one do it? anyone ever tried a flat iron? (the thing you use on shirts). ::)
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Just use a heat gun to flip the tips. Steam is good for statics.
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Funny you'd suggested a flat iron, I've wondered about it too.
I got a temperature controlled hot air gun so that I could work out what I was doing (since then I managed to break it), however once you have the knack it's ok with an ordinary hot air gut (at least 2000W).
The mistake I made when I started was going too hot too quick and just scorching the surface layer, the second mistake was not giving it a couple of days to re-aclimatize.
To do it right you should get bored rigid thinking nothing is happening, just when you are about to give up you notice the wood is maybe darkening a tad? Then it starts going a deffinite honey, then brown. All this time you are wafting it about an inch above the wood and you are wishing you'd made a jig to hold the hot air gun.
To do one limb takes about 30-45 mins, that gives you some idea.
The problem is with a jig, you go indoors and start to watch TV and forget while the wood is scorching to a crisp >:(.
The great thing about a hot air gun is you can bend and heat treat at the same time. But leave it clamped up for at least 2 days (I usually try for 3 'cos I know I'm an impatient old git)
I can PM you my heat treating notes with actual temperatures if you get a temperature controlled gun if you want me to.
I still use steam for some jobs, there are pros and cons to both.
Del
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IMHO it would be rather difficult, if not impossible, to make a working recurve selfbow out of maple. As for using heat guns, you have to heat the back to bend the tips. That means, you have to make a static recurve. Anyhow I would just flip the tips making it static, just enough to compensate for any string follow.
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scp,why do you have to heat the back to bend the tips :-\ I never do.
Pappy
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Im with the steam bend followed by dry heat school of thought. Working recurve selfbows are a like walking on a knives edge though....I would go for a static recurve.
Also...those initial 2" of reflex are on the low side...as is the 4".
Cheers
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scp,why do you have to heat the back to bend the tips :-\ I never do.
Pappy
I also used to use the heat gun only on the belly side. Then I broke a couple of tips and that got me thinking. It happened mainly because I was impatient and used too high temperature too close to the wood. But I also realized that for bending wood in boatbuilding we usually heat the wood "on the inside of the curvature."
Cf. http://koti.kapsi.fi/hvartial/bend/bend.htm
Now I heat the back side when I flip the tips.
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Boat planks stay bent, they arent asked to bend back and forth 15" several thousand times. And they are generally sawn on both surfaces. Heating the back of a bow is a no-no no matter who ya' is.
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Boat planks stay bent, they arent asked to bend back and forth 15" several thousand times. And they are generally sawn on both surfaces. Heating the back of a bow is a no-no no matter who ya' is.
Even for static recurves?
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Statics require steaming most often with most woods.
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That's not at all unusual for a whitewood. 2 in of set is par. What's the solution? Just make a bow and enjoy. Jawge