2 layer vs 3 layer laminated R/D Bow

[vanduzer]

I have hickory for the back,  and I bought some black locust for the belly.  Now I am having a feeling that I should glue these two woods together and then tiller.  For insurance I was considering adding bamboo to the belly.   I plan to use a smooth on ea-40 epoxy.  I also plan to put this 68 inch bow on a form with a 2 inch block on the ends and a 1 inch block in the middle and securing with u bolts. I plan to cook at around 160 for 3 hours.     I have made a few bows and I have had most of them brake.   So any input would be valued.   Some questions that have crossed my mind today.  1)  can you temper black locust with a torch like you can with bamboo.   2)  having my wood layers looked good.  when I tapered the black locust today I put the scraps in a vice to test flexibility and strength.   I had some results that showed that the wood could be bent at a decent rate.  The scrap pieces all broke.   This is what prompted me to tiller the bow down to 40lbs and then attempt to add a thin piece of bamboo for the belly.      thanks for suggestions....   I learned some of what I have practiced through rudderbows.     I have questions on design, materials and technique but I guess that is why I am on this forum : )      My goal is to have a 55 - 65 pound somewhat fast bow for hunting elk and deer.

[HickoryBill]

First off bamboo is way way better in Tension( backing) than compression( Belly). If you want a tri Lam I would do a bamboo.locust.hickory.or a Bamboo hickory locust..Hickory is an excellent belly wood. To answer one of your other questions BL will temper( heat treat) very well with dry heat and a little oil.When the wood starts to  golden brown and smells like buttered popcorn your there.. usually 10-15 mins for each limb...

[vanduzer]

Thanks HickoryBill.  What is the method of dry heat for the BL.  Could I put it in my heat box?  And would mineral oil or linseed oil be ok to use ( i have both of these)?   Does this change the cell composition making it less likely to break under tension?

[mikekeswick]

You can heat treat b.locust and it will respond very well. However you cannot heat treat a laminated bow as you will certainly ruin the glue (any glue). You could heat treat a belly slat before glue-up but thats pretty much a waste of time. Heat treating basically makes the bow better in compression - if anything it makes a bow MORE likely to break in tension if it is overstrained or has any flaws in the back. A simple way to do it is with a paint-stripping heat gun. Heat till the wood turns to medium brown.
Uncut wood fibers end to end of the back will make the bow virtually un-snappable (clauses...).

[blackhawk]

Heat treating a belly core pre glue up will help IF it is a well pre tillered belly.<----key words
I know marc heat treats some of his bellies in his composite bows pre glue up. Hopefully he'll see this and give his experience with it.

[vanduzer]

thanks for advice.  I was also wondering if a board bow once nicely tillered can be reinforced on the belly with bow tuff fiberglass?  If this is a good practice how many added pounds can you expect to put back on the bow with the one layer of fiberglass?  I am only doing this for insurance.  I thought maybe I am being paranoid and was wondering if my belly of the bow (black walnut) would be okay with the hickory backing.  I know no guarantees but just wanting to use the best techniques for durable board bow.   

[fishfinder401]

aaaaaaaaaaaaaahhhhhhhhhhhhhhh, he said the f word