I was bending a thin piece of natural bamboo around one of the fades in the riser when I pushed a bit too hard in one spot and cracked it up the middle for about 4 inches. I filled the crack with super glue and I was able to clamp it in place without a problem. I left it like that for a day and it was ok, but when I was removing the clamp, I put my thumb in the wrong spot again and it cracked a bit farther up, but not in the repaired area. I filled it with super glue and the crack is closed, but now I wonder if I should even use this lam in the bow.
This bow is only dry fitted and not yet glued up. Any thoughts?
Dave.
I'll throw my 2 cents worth in and reckon that if it was a glass backed bow then it would probably be ok as any stresses are either in extension or compression and not laterally. Sort of like the glass and epoxy holds it in place and it would be highly unlikely to be able to 'spread ' under the glass and other lams.
Hi David,is this a glass bow?I had this on an all wood bow that i built but it showed up after glue up.But anyway,IMHO i wouldent take the chance.A person spends to much time and money building a bow to take a chance in using materials that your unsure of.I know if it were me and i used the piece of bamboo and it gave me a problem i would be very unhappy with myself for not just replacing it in the first place.But im always thrilled even if i have to get another piece when a bow turns out the way i intended it to.I also agree with bigbob.But if there was any doubt in my mined i wouldent chance it.
Sorry guys. I should have mentioned that this is an all bamboo tri-lam. It's one of the belly lams that has split. I kept thinking about it last night and I was going to replace it. Even if it glued up ok and didn't cause any more problems, it might show in the finished bow and I don't want that.
Thanks for your input. :thumbsup:
Dave.
Woodcarver, what are the thicknesses of the three lams?
I've only seen pics of one all boo bow, but this is interesting.
Red, this bow is a bit of an experiment. It might come out a bit light, but I just want to see what happens, then adjust for my next one.
The back and belly are natural boo that's just over 1/8" thick, tapering to 1/16" at the tips. The centre lam is also natural boo planed both sides to 1/8" and I made a jatoba power lam 26" long by 3/16" thick. The riser is a nicely figured piece of walnut 14" long and the bow is 1 3/8" wide, tapering from full width at the ends of the power lam to 1/2" at the tips. I might thin down the tips a bit for looks later.
I don't know if it's a great idea to use a planed piece of natural boo for the centre lam, but I figured that being sandwiched between the back and belly it should be ok. Other all bamboo bows I've seen were made of only a back and belly lam and the lams were thicker.
I almost forgot to mention, I took my blowtorch to the belly lam and toasted it black. I also singed the back for looks.
I'll post pictures after I glue it up. Right now I'm heading out to the garage to prepare some more bamboo to replace the belly lams.
Dave.
I've been working on this bow for a bit now and it's coming along. I have a question though. I've done a bunch of sanding and the bows width is now 1 5/16" and it's 2" from back to belly through the riser. I'd like to cut a shelf into the riser, but I'm not sure if it would be safe to cut to center. I'm aiming for a finished weight around 55#. The minimum weight allowed for moose hunting here is 49# so I don't want to fall below that.
Any thoughts?
Dave.
I wouldn't chance it.
Maybe I'll cut in a shallow shelf then. Roy, you missed your chance to get in a long distance thumpin! all you had to do was say "yeah that's a good idea" and the bow would have done your work for you. :)
Dave.
I didn't wanna see the bow get hurt:)
Why ya wanna cut in a shelf Dave? Ya looken for closer to center shot ya big sissy pants? LOL
My yew bow has the widest handle of any bow I've ever made and it shoots better than a lot of my other bows.
Here are some pics of the bow so far.
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0451.jpg)
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0452.jpg)
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0454.jpg)
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0455-1_zps23d2a5a3.jpg)
I don't know what they've done to photobucket but it stinks now. People can't leave well enough alone.
Dave.
That is sharp dude. On photobucket in the upper right hand corner is a little link that lets you switch back to the old photobucket. I never tried it yet but might. Ya know as wide and deep as that bow is ya might get away with cutting in a little shelf.
That is the old photobucket. it's buggered as well. Where it used to take a few seconds to re-size a picture and post it, now it's a fight and some come out big while others come out small. :banghead:
Anyway, I'm glad you like the bow. It's a candidate for the swap.
Dave.
That kicks a**. I don't even think twice about cutting a bow to center. I do it all the time. If your riser is 2" thick you're good to go. Just make sure you've got at least 1/2"-3/4" of width remaining in the sight window portion of the riser.
I'm thinking of going in 1/2". That will leave a bit over 3/4". The 2" of thickness includes the riser and lams. Back to belly.
Dave.
Well, I was showing this bow to a friend today and I decided to string it up. I got out a string that's 3" shorter than the NTN length and put it on. I was shocked to find a hinge in the upper limb, just shy of midlimb and just past the end of the power lam. In the larger picture above, the hinge is to the left of the node at the edge of the table, about midway between the nodes. You can just see where the power lam ends.
I'm at a loss as to how to fix this one. Up till now I had been using a slightly longer string and the limbs were both bending exactly the same. I had been tillering by scraping and sanding at the edges only, so that I don't take away the bamboo belly. I can't use the gizmo on it because of the natural boo belly.
Any ideas?
I hope this one isn't firewood. :pray:
Dave.
Have you been tillering by removing material from the belly?
It sounds like where the power lam ends there is,too much transition. The only way to fix it is to remove wood from the belly from each side of the hinge. Then even out on the other limb.
Probably keep you from hitting weight.
I'm wondering if having the power lam that long caused the problem in the main working section of the limb.
Dave,
The bow looks great. Bet it shoots good too. :thumbsup:
Pictures of the bow strung? I have done two with bamboo bellies and other than scraping from the sides you can "knee tiller" any stiff spots out, but I don't know about hinges. Unless the rest of the limb is too stiff causing the hinge.
David, wait till you see that hinge! You might have a change of opinion. I'll have a couple of pics in a few minutes.
Dave.
OK, here are the pictures. I'm wondering if the node on the belly just to the right of the hinge is causing a stiff spot.
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0459.jpg)
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0460.jpg)
If you look close, you can see that the power lam is bending nicely.
If I were to sand the node area down some, will it help?
Dave.
Man hate to say it but by the time you get the hinged limb even close it will take a lot to to even out the other limb.
For some reason that area was just weak.
It might be a good learning experience trying to fix it.
I guess there are a lot of unknowns with natural materials like bamboo. I'm going to try and save it. I'll sand the belly outside of the hinge, then even out the other side. I can then shorten it or make a kids bow.
Dave.
IMO I would try to knee tiller the stiff areas. If you sand through the power fibers of the boo I think it will make it extremely weak in those areas.
I'm not sure I know what knee tillering is. When I bent the bow over my knee, both limbs felt the same. What I don't get is the other limb has the nodes placed in almost exactly the same locations as on this limb.
Dave.
Knee tillering is where you actually bend the limb in a very specific area (over your knee) to cause targeted set. You bend it just far enough to manipulate (sounds better than crush :) ) the belly fibers to achieve "more" bend in that area. It works really well with bamboo bellied bows.
I knee tillered mine when it was strung, did a couple of pulls and rechecked tiller until it was acceptable.
Woobcarver 2,I am no expert on bbb's by any means but from where you are i would sand the nodes off the belly completly and ajust the tiller WITH OUT PULLING IT MUCH or it will blow, then toast up another piece and try to keep the nodes away from the end of the p-lam. tiller the new piece before you glue it on.Ajust the weight with the width--Joe
Thanks for all the advice guys. All I need now is some good luck.
Dave
VB, that will be what I do if I can't sand out the problem. I have another toasted bamboo slat that I can replace the belly lam with. If the weakness is in the core, then I guess the whole thing is toast.
Dave.
Nick, thanks for the tip about knee tillering. I had heard of it before, but I'd forgotten . Last night I strung the bow and bent the good limb over my knee. Lo and behold, the tiller is almost even now! I was afraid I would have to take drastic action or cut it up for firewood, but now it looks like I might end up with a bow. :archer:
When the weather warms a bit, I'll get out and put some tip overlays on it and finish tillering.
Dave.
QuoteOriginally posted by wood carver 2:
Nick, thanks for the tip about knee tillering. I had heard of it before, but I'd forgotten . Last night I strung the bow and bent the good limb over my knee. Lo and behold, the tiller is almost even now! I was afraid I would have to take drastic action or cut it up for firewood, but now it looks like I might end up with a bow. :archer:
When the weather warms a bit, I'll get out and put some tip overlays on it and finish tillering.
Dave.
Sweet! I know it sounds sketchy, but it works :)
Right on, good save.
Ok you saved it!! now post a dang picture of it.. this thing is gonna be killer if you finish it out. I love the toasted look of the bamboo. Does that do anyhting to the bamboo itself or is it just for looks??
Justin
Sorry for not posting. :o I was busy with doing inventory at work and I didn't get any work done on any of my bows. :mad: I hate inventory, the company they hired made a mess of it.
Justin, from what I learned here, toasting the bamboo for the belly tempers it. I like the look as well. I torched the back lightly just for the camo look.
I want to get some more work done, then I'll take some pictures of it.
Dave.
Ok, I went out and took some pictures of the bamboo bow. I drew it to 22" and it hit 40#, so it should make weight. The only problem is it looks hingy ( is that a word?) on either side of the power lam.
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0470.jpg)
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0463.jpg)
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0461.jpg)
Here it is drawn to 20".
In the next one it is drawn to 22".
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0464.jpg)
The right limb looks like it has a hinge, but it might not be as bad as it looks because there are nodes on the back and belly that distort the curve of the limb. The right limb is the upper one and it's 1/8" positive tiller.
What do you more experienced bowyers think?
Dave.
Those would be hinges at thd end of the fades. But with 40# at 22" you should still make weight.
Work those hinges out and you'll be looking gooooooood.
Overall I really like the bow.
Would sanding / removing material from the edges of the limbs from just outside the fades to just shy of the tips work? I'm not sure that I can remove much from the belly.
Dave.
Hi Dave
I really like the bow and the color of the backing- ist this dye after removing the boo`s wax?
For tillering you can even try trpping the limbs- but I guess thats nothing new to you^^
Hi Moe, I'm glad you like the bow. I colored the back with a butane torch. I also torched the belly lams to temper them. I like the charred look.
Dave.
Oh cool I wonderd for some time how the boolams in the cazadors limbs get this nasty look ty-
but for a backing I would worry about the influence on the boo through that heat treatment, but if it still works you`ve done the right job!
Dave ya need to work on that bow or it might break at those hinges. If ya can't take wood off the belly, then narrow the limbs a little at a time equally on each side.
(http://i47.photobucket.com/albums/f165/ROY-CHRIS/dave_zpsd3134f1a.jpg)
Thanks Roy. I'll be scraping and sanding in those areas.
Dave.
Love the graphics, Roy! Such artistic flair! :p :p