Bamboo backing, glue & finish question

[TomBow]

Glued bamboo backing to hickory with purple heart handle in the works.  Glued with Titebond III and worked in some reflex, 2+ inches at this point prior to any tillering. etc. Today, I read that Resorcinal should be used.  Since I didn't use Res. and used water-soluble Tite-3, should I be concerned about de=lam?  Other question is about finishing this bamboo hickory, If I get lucky this time and produce an actual shooting bow that doesn't break after tillering and being shot in, what are some suggested finishes to use to waterproof the bow?  I have some tung oil, stain, wipe-on poly and access to other finishes, should I need.  Just a few expert opinions would help me narrow it down a bit.  AGain, so far the bow looks good with the bamboo/hickory/purple heard.  Any info will be greatly appreciated.

Thanks,
TBow

[Pat B]

If you applied the glue and prepped the glue surfaces as per the directions you will be fine. TBIII is a very strong glue. I've used it a lot with backed bows and never had a glue failure.

[Mad Max]

any sanding scratch can break a bow

removing ALL scratch's is important

my 2 cents

[wood carver 2]

TB3 works great for wood and bamboo bows. It also offers the advantage that a damaged backing can be removed with a little heat.
As for finish... lately, I have been using a spray application of shellac, followed by multiple coats of polyurethane. I find that the shellac is pretty good at filling pores.
Dave.
P.S. you can't describe a bow like the one you're building and not post pictures.    

[Eric Krewson]

I disagree with the sanding scratch/bow failure suggestion because it just isn't so.

I pep my glue surfaces with a toothing plane iron, big, deep scratches on the back and bamboo belly. 50 BBOs out of my shop so far and not the first bow failure from a "sanding scratch".

That said, I know for a fact if you scrape the rind off your bamboo too aggressively you are setting yourself up for a bamboo failure somewhere down the line.

My advice is to scrape just a little and sand the majority of the rind off. I leave any rind that is in the normal tiny valleys on the back of bamboo slat. This remaining rind leaves a neat streaked effect when stained.

 

[Bowjunkie]

Eric, I think perhaps younz are talking about two different backs. Aren't you talking about prepping the back side of the core wood? ...and belly side of the bamboo?

I assumed Mark meant a scratch left on the outer surface of the bamboo (bow's back) can lead to breakage? But I could be wrong.

I do exactly as you do when it comes to prepping with the toothing plane (I glue up with gap-filling Smooth On), and treat the rind the same way you do. I'm especially careful not to create nicks in the bamboo with my scraper(with a small lightly rolled burr), or sand too much attempting to remove every trace of rind in the little valleys. I also dont touch the back of the bamboo with anything more aggressive than 240 grit red oxide paper.

I dont have breakage or splintering issues either... knock on wood :^)

[Paul/KS]

What is your glue of choice Eric..?

[Eric Krewson]

Urac until I run out then Unibond.

[LittleBen]

Yeah I think you were right here Jeff .... And that would make both mark and Erik also right.

Bad scratches on the backings outer surface is not ideal.

TBIII is awesome, but the main reason I finally stopped using it is cause it's water based and makes the wood swell when you glue up  then the woods dry at different rates and for long after the glue is cured, and it causes an edge at the glue line you can feel, and I think I read somewhere that the two pieces shrinking different amounts weakens the joint.

Been using smooth on and it's solved all my problems and more.

[Paul/KS]

Thanks Eric.