BBI Questions - Belly Crack and Tip Overlay Glue (Pict Added)

[bridog]

Hello All,

I'm in the final stages of making my first BBI r/d longbow.  The bamboo is trapped.  I used the Torges method of tillering with facets.  I have the bow to within a couple pounds of final weight (50), 51-52lbs at 28".  I have the tiller 3/16" more on the top limb for 3 fingers under.  I have the handle and shelf +-85% where i want it.

I decided to sand out the limbs - When I did i found a 3/16" wide check in the wood that goes perpendicular to the length of the limbs.  It is near the side of the bottom limb about 8-9" from the fade.  It does not go out the side of the limb.  It is hairline.  I tried scraping some wood to see if it would come out but it is still there.  I did not want to take to much wood as I did not want to loose weight and affect the tiller too much.

Is this going to give me problems?

What caused the crack or is it just crushed wood fibers?

I also have a question on what type of glue to use for glueing on phenolic limb tip overlays with ann osage accent on top?

Thanks much for any insight you may have.

Brian

[bigbob2]

Cant help about the crack but the only glue I use is smooth-on for the risers, tips and lams.

[macbow]

Hard to say but I'd keep an eye on it maybe mark the length.
Do some more break in shooting to see if it changes.
A fret or Crysal (compression) failure usually end up wider than that on mine.
Look the bow over from the side with good light. In that area is there any dip in the thickness to make a weaker compression area?
Only time will tell.
A good close up photo will result in the real bowyers helping out.

On using phenolic I'd use smooth on.
Ron

[PEARL DRUMS]

Thats a fret and its because your tiller is off and that section is working too hard. It will get worse odds are.

[SportHunter]

A deep penetrating glue is Locktite 420, it's expensive but it will seep into to crack. Post up some pics of your tiller & problem area.

[bridog]

I'll try and get a picture and post in the next day or 2...  thanks for the input so far.

Brian

[bridog]

Here is a picture of the crack at brace height of 6".  It is in the lower limb +-8" from the fades.

Thanks, Brian

[PEARL DRUMS]

Thats a compression fracture and glue wont help it all. Your fades are probably stiff causing that area to work too hard. Loosen them fades up.

[bridog]

Here is the bow drawn to 27.5".  Kind of tough to see with all the stuff in the background.  Lower limb is to the left with the crack being about 8-10" left of the fade.  The total bow length is 66".

Thanks much, Brian

[PEARL DRUMS]

Yup. Stiff as ever. Your right limb is almost dead straight, Im suprised it didnt form fractures first. Get that tiller ironed out before you pull on it anymore or your jepordizing its survival.

[bridog]

Some questions on your comments...

Where is it stiff? - I'm having a hard time seeing where I need to take wood off.  I was told the limb end are supposed to be stiffer for this style.

To loosen up the area around the fracture - Do I take wood away on both sides for an inch or two and skip the exact spot where the fracture is at?

This bow has a high reflex/deflex profile.  I will post picts of the unstrung and braced profile for reference tomorrow.

Thanks, Brian

[Colorado Joe]

If you have a chance I would love seeing a side view of your tillering board. Nice construction.

[bridog]

Joe,
If you email me at [email protected] I'll send you a pict of it.  I'm having a heck of a time posting picts to my photo-bucket and uploading picts.  If you can believe it I still have dial-up...

It's a combo tiller tree and pully set-up.

Brian

[horseapple]

looks like a chrysall to me, are you pulling the bow to draw length and then leaving it while taking pictures? I built bows with that tiller for just a short time until I smartened up and tillered the limbs to work to about 6" from the tip, lots more success    also use ea 40 for the phenolic and always use urac for wood to wood.

[Sam Harper]

Horseapple, this is off topic, but since I haven't seen you around in a long time, I thought I'd go ahead and ask.  You used to have a tutorial a long time ago showing how to do a fiddle back stain on the back of a bamboo bow.  I practiced and practiced with various kinds of dyes (including aniline) and various ways of applying it, but I could never replicate your design.  Has your tutorial ceased to exist, or did you move it somewhere else?  If would be awesome if you could video tape yourself putting a stain on a bamboo bow and posting it on youtube.  A lot of people have asked about how to do really cool stain jobs on bows like yours, Vinson Miner's, and James Parker's.  The answers that come back are usually kind of vague.  Help us out, J.D.   Make the world a better place.  Post a video on youtube.  :-)  Please???

[horseapple]

Hi Sam, I still have the tutorial on cd, prob not gonna see me on what you call youtube    most important part of making the stain look good is sanding the waxey resin off the bamboo, then the aniline dye will adhere to the boo.