Primitive Archer

Main Discussion Area => Bows => Topic started by: DC on November 08, 2014, 12:37:11 pm

Title: Flattening bamboo
Post by: DC on November 08, 2014, 12:37:11 pm
Is it possible to flatten bamboo? I mean split it and soak, steam,boil or heat it to take some of the curve out so the split pieces are wider. I did a search and mostly I get people rasping, planing and sanding the inner surface to make it flat for gluing.
Title: Re: Flattening bamboo
Post by: simson on November 08, 2014, 02:48:39 pm
IMO no!
you have to work it down
Title: Re: Flattening bamboo
Post by: Badger on November 08, 2014, 04:51:49 pm
  Bamboo is pretty much uni directional in its properties, I would imagine if you were to split it into 1/4 wide pices and square the sides back up and glue it back together it would behave pretty well. I think the small natural crown we get from bottom flattened bamboo actually works out better than flat though.
Title: Re: Flattening bamboo
Post by: DC on November 08, 2014, 08:51:10 pm
Thanks guys. I didn't think it would work but I had to ask. I got a 3" dia bamboo log from a garden center. If I was to split it and plane it flat and 1/8" thick it would be  about 1 1/4" or so wide. I thought that if I could flatten it a bit I could get wider strips. I will probably be using it as a backing for left over yew heartwood so it will probably do for that. Thanks
Title: Re: Flattening bamboo
Post by: PatM on November 08, 2014, 09:03:17 pm
The Koreans successfully flatten it as core for their horn bows. not sure if it's worth doing that for a backing. It's capable of being crowned. Think of a bamboo fishing rod and the stress it can take with sharp corners.
Title: Re: Flattening bamboo
Post by: duke3192 on November 08, 2014, 10:42:56 pm
The Koreans do it when it is green, and then season it, I know a fellow that has done it, when green, by just soaking in water.
Title: Re: Flattening bamboo
Post by: DC on November 08, 2014, 10:54:34 pm
This is bone dry. It's been sitting in the corner of this garden center for a long time.
Title: Re: Flattening bamboo
Post by: DarkSoul on November 09, 2014, 06:51:51 am
A bamboo backing can be narrower than the wooden core/belly. It will create an artificially trapped back. A 1" wide bamboo strip is great for a 1½" wide bow. Works especially well for less compression strong woods such as oak, juniper and many white woods with iffy grain. A full width bamboo backing would otherwise overpower these bellies.
Title: Re: Flattening bamboo
Post by: Richard Tipton on November 10, 2014, 09:51:15 am
You could glue thin strips together(action boo), just make sure you offset the nodes. I've used bamboo for years and I only use slats cut from 6" or greater poles, it's flatter.
Title: Re: Flattening bamboo
Post by: Springbuck on November 12, 2014, 05:32:00 pm
  I once flattened a piece to use as a backing, and then I torched the pith side to correct a crook.  Not the outside, you understand, which would be kinda dumb for a backing.  Anyway, the glue side was flat from sanding, but then bulged as it was heated.  The back flattened and the flat glue side bulged out slightly in the middle.  So, I did the whole thing and re-sanded the glue side flat.

So, it flattened it flatter than it was, but not all the way flat, and I still used it as a backing, no problem. But not flat, flat.

Is your boo just too small in diameter?
Title: Re: Flattening bamboo
Post by: DC on November 13, 2014, 03:45:02 pm
Is your boo just too small in diameter?

Yes. The 3" piece was $35 and the 4" was $85. My Scottish ancestry won out. False economy maybe?
Title: Re: Flattening bamboo
Post by: bushboy on November 13, 2014, 06:29:39 pm
Whow!those prices seem outlandish, I can buy a 3"x8' for 8 bucks and a 4x8' for 40 here in Canada and every thing is more pricey up here maybe save maple syrup.ive only used the smaller boo cause my lastname is Maclean!lol!bamboo is great stuff albeit a lot of prep and hard to get a descent glue line with.i have found with 3" I can get half that as a slat.boo will overpower most woods save ipe and osage.
Title: Re: Flattening bamboo
Post by: duke3192 on November 13, 2014, 09:49:07 pm
How thin are you going with your bamboo backing, you need to get it down really thin, especially at the tips, 1/4 to 3/16" at center to 1/8" at tips.
Title: Re: Flattening bamboo
Post by: DC on November 14, 2014, 01:44:49 am
This was the only bamboo handy and $35 wasn't going to kill me. Sometimes I'm a bit of an impulse buyer. If I can go 3/16" tapering to 1/8" I won't have any trouble with an average bow of mine. I was thinking 1/8" all the way and that left me a little shy of width close to the handle. I'll work it out.
Title: Re: Flattening bamboo
Post by: mikekeswick on November 14, 2014, 02:13:57 am
I'd say look for another source at those prices, bamboo can be bought much cheaper than that.