Question about floor tillering and making target weight with heavier bows

[Sandsquid]

I've been trying to make a heavy weight ELB for two years now.  I've had some success with bows under 100 lbs, but can't seem to get north of 100 lbs without the bow taking a large amount of set.  The bows I've made have held together they just are not very fast shooters.  I've feel my failure begins when I first try to brace the bow.  I've been a bad judge of where I'm going to end up in lbs.  I feel by trying to brace a bow that is way over target weight I'm putting unnecessary strain on the limbs.  My successful bows under 100 lbs were mistakes.  I was tricked by the reflex in these staves.  These bows were real stiff until I braced them.  Once braced they lost weight quickly.  They did manage to hold some reflex and seem to be fast for their weight (at least compared to other bows I've made).

At the moment I'm working a piece of white mulberry.  This is my first time working with this wood.  The stave had a slight propeller twist, reflex/deflex in one limb, deflex in the other, and decent size knots on the inner 1/3 of each limp.  I've steamed every thing mostly straight and plan on heat treating the belly.  The handle is 1.7" wide by 1.15 thick.  NTN will be 76" (I would have liked it to be a little longer but my dad cut the log a little short).  I'm shooting for a final weight of 120-130 lbs @ 30".  I have each limb bending 8" and everything looks pretty even on to me on my tillering tree.  At this point the stave has taking about a 1/2 inch of set.  I think I'm going to heat treat now and let it sit a few days before moving forward.  I just hate to make the same mistakes again.

Does anyone have any tricks for making target weight for these heaver bows?  Any suggestions on methods for getting the bow to a brace?  Does anyone have experience with mulberry in heavier weight ELB?  Any advice would be appreciated.

[Pat B]

Looks like your right limb is bending more than the left and most of the bend is at mid limb.
 You might also post this in the War Bow section. You will get more and better advise there because those guys are more familiar with tillering heavy ELBs.

[Badger]

   You don't have to guess at it at all. When you are tillering the bow and using the long string read it just as if the bow were braced. It does not change much when you brace it. So if you want 120# @30" then pull the bow to 120# each time and just keep correcting the tiller until you get to 28". Once you get there you can brace it and finish tillering. If the bow starts taking too much set on the way you will need to lower your target weight.

[bradsmith2010]

maybe you will need to use more wood if the bow is taking  too much set,,wider longer, etc,,

[willie]

If the bow starts taking too much set on the way you will need to lower your target weight.

or

wider longer, etc

or
lesser draw length
or
use a more elastic wood

the above covers the design possibilities If your bows are taking their set evenly all along the limb. If not, try tracing the rested limb as you tiller to in order to locate your problem areas as they develop.

how much set would you be happy with for a 77" bow? 
a pic  of an earlier bow at full draw will eliminate some guess work by others commenting

[Del the cat]

Heavy bows are tricky, I can't imagine that it's even possible to floor tiller! If you can flex it enought to see the bend, then it's probably already too weak!
Like Badger says, you need to keep with the long string until it's coming back a good way. Even then you may need a winch to brace it!
Any stave with reflex becomes a nightmare, behaving exactly as you have described, ridiculously hard to brace and then dissapointing.
You need good wood, a long stave and nerves of steel!
Good luck
Del

[Sandsquid]

Thanks for your replies.  I know some of my earlier problems were design issues.  I was too short, too narrow, and tapered the width too quickly.  I was originally working with slippery elm which I am confident would make a good heavy weight ELB.  Problem is I ran out of staves and have not been able to source more.  I had some hickory I was working with.  All the staves were from the same log and were just not very good.  After drying they all took deflex in one end of the stave.  I'm thinking it had something to do with the growth rings.  The outer 10 rings were almost paper thin.  I ended up chasing a ring on every stave I worked with to get to good rings.  Even after I steamed the staves straight, it seemed like only the original deflexed half wanted to bend.  I did make a couple of bows that I do shoot.  They are just slow and ugly.   

I'll spend more time with long string and not be in a hurry to get the bow braced going forward.  We will see were I get with this mulberry.  I'm worried about the right limb.  There is a little bit of an s bend in the mid limb.  It was bending more than it should there and is starting to twist a little.  I originally set this stave aside because of all the straightening I had to do on that limb.     

[bradsmith2010]

ok also, its not all about how it looks,, if it bending evenly,, even with set,, it should shoot well,,,

[Selfbowman]

   You don't have to guess at it at all. When you are tillering the bow and using the long string read it just as if the bow were braced. It does not change much when you brace it. So if you want 120# @30" then pull the bow to 120# each time and just keep correcting the tiller until you get to 28". Once you get there you can brace it and finish tillering. If the bow starts taking too much set on the way you will need to lower your target weight.

This !

[willie]

Even after I steamed the staves straight, it seemed like only the original deflexed half wanted to bend

steam bending works well for sideways corrections or flipping non-bending tips, but if you remove deflex (or add reflex) to a working section of a limb and it pulls out is not unexpected.

[Bruce M]

   You don't have to guess at it at all. When you are tillering the bow and using the long string read it just as if the bow were braced. It does not change much when you brace it. So if you want 120# @30" then pull the bow to 120# each time and just keep correcting the tiller until you get to 28". Once you get there you can brace it and finish tillering. If the bow starts taking too much set on the way you will need to lower your target weight.

Thank you for taking the time to type this response, it helped me immensely with my own struggles with tillering.