boo backed R/D longbow help

[razorsharptokill]

A few years ago I started to build some bows using boo for backing and kickory for the cores. I leaned more toward the laminated fiberglass bows due to the more predictable out come. Now I need a change of pace.

I have a lam of hickory 3/16 thick rough shaped for a long bow. I have my boo rough shaped also and sanded flat but not quit knife edged yet.

I have the hickory tapered from 3/16 at center to 1/8" for thickness at the tips and 5/8" wide. I plan on using a form to add the r/d.

Now... my question. How thick should my osage be to get it to glue up on the form with my boo and hickory?

[Walt Francis]

We need to know what weight bow you want to end up with, 5/8" thick would be a good starting point for a 60# bow with the hickory core.  It is better to be too thick then too thin.  You might have to use clamps to get the Osage to bend if your R/D is severe.  When I use anything over ½” I heat the Osage and bend/reshape it in the form then let it cool completely so it has that shape before gluing up the bow.  I found by doing this my BBO retain the shape of the form when removed and hold that shape better during and after tillering.

[mmgrode]

Yes, as Walt mentioned it is better to start out a bit heavier and work it down to the weight you want.  With that setup(depending on how much r/d you put in) I would say somewhere around 1/4" to 3/8" parallel for the belly osage. Typically trilaminates like you're making hold most all of the r/d off the form.  I typically prefer a bit more taper in my limbs, but that is how it bends on my form.  What kind of form are you using?  Good luck and don't forget the pictures!  Matt

[razorsharptokill]

I've had these two pieces of material for a while, I think the hickory core is 65"? I'd like to shoot for 55-60.

So if I could get some billets spliced (or a long enough board) I could just rip a 3/8" piece to use huh?

Has anyone ever put glass under the boo and on the belly over the core/ Seems like that would make a light quick limb.

[mmgrode]

Yes, just rip out a 3/8" thick piece of osage, sand it up, and glue it up! You can always take osage off the belly to make weight.  If you're talking glass you'll have to get someone else to chime in.  Good luck, Matt

[razorsharptokill]

I can't remember who it was here that built the form that I duplicated but they work with CNC machines I believe and used a computer to draw the plans. I did a search but couldn't find the post. Here's a pic.
 

[razorsharptokill]

Measured the length at 68". I was planning on taking the handle portion a little higher( away from the blocks) than this bow was.

i need to find some osage now and get it spliced, ripped, and glued up!

[razorsharptokill]

How does this profile look? Should I lower the height of the little blocks? It seems like it would give it a better flow.
 

[elk ninja]

Hey Jim,
Looks good so far my friend!  Here's a link to a website that I really like, this guy is pretty amazing what he makes in his apartment... similar form, a little less in the tips I think, so take a look at his final product and decide if you want more or less definition in the reflex.  good luck, be sure and keep us posted with LOTS of pics.... speaking of which, it's been a while since I've seen a good build along!
Mike

[elk ninja]

http://www.geocities.com/salampsio/ipe1.htm
whoops, forgot the link.
Mike

[razorsharptokill]

Here's some pics of todays shop time. Here's the Osage I picked up today. It was 71" long 7/8" thick and 1 1/2" wide. I ripped it to 3/8" and put it on the form with my hickory lam and hit it with the heat gun.
 
  I think the little blocks need to be reduced in height about a 1/4". It looks like there is a flat spot there.

Ok... glue question. Is smooth on good for all wood/boo bows? I have a heat box that will hold this form. I also thought about putting the lams on the form and cooking them for a while before glue up to get the memory into the osage.

[razorsharptokill]

Love that link elkninja! Thanks, and Semper Fi.

[razorsharptokill]

TTT

[Walt Francis]

Warming the wood before gluing it up is always a good idea, but with your tri-lam design don’t heat it to much.  Also, watch that the wood doesn’t get too dry.

[razorsharptokill]

Good point. I have it in the form in my father in laws shop. I better get it glued up soon huh?

Now back to my glue question. Can I use Tite Bond III or do I need to use smoothon or uraq? I'd like to save my smoothon for my glass bows.

[wingnut]

Urac is best, smooth on is good and both are better then titebond.  You can use it but don't cry if it fails.  LOL

Mike

[razorsharptokill]

Better safe than sorry. I had a handle pop off using Titebond III once.  Thanks, I think I'll just order some urac. Where is the best place to get it? can it be found locally or is it a special order item?

[razorsharptokill]

Never mind ... just ordered it from Nelson Paint.

[razorsharptokill]

Ok.. saw another BBO post and I noticed that during the glue up the handle section was left off.

I like the Dryad "Soothayer" style handle so my handle is going to be several layers of bocote, padauk, and Kingswood. I guess I'll have to do it in layers to get it to make the bend in the handle huh?

Another thing.. do I center the handle section or favor lower than center to help with tiller?

[Steve Kendrot]

I'm about to start my first BBO too. In regards to the small blocks, I wonder if you even need the mid sized blocks. In Dean T's video, the form he uses has blocks under the tips, mid limb and handle only. Seems like it would flow more smoothly without forcing it to hit both sets of mid limb blocks. Maybe??