Tip Reinforcements for non-B-50 Strings

[KellyG]

Ibehiking I have been reading the traditional bowhunter's handbook. I there it has B-50 with a minimal stretch of 4% and a .018 diameter 45# per strand and Brownell's FF .9% stretch, .015 diameter and 95# per strand. So there is a big differnce in the absortion of energy. On brownell S4 newer had .9% stretch, .018 diameter and 167# per strand.
Now do your math thing.

[Dave Worden]

With Dano's/Pat's bow thrown in the mix, does the confusion increase?  No treatment/reinforcement for the tips, FF, and it still works?!!!!!  
On the couple of longbows that I've made, I reinforced the tips with Dymondwood (cut-offs from the riser).  If you cut through the tips, you'd have a tear drop shape with the "sharp" end of the tear drop on the back of the bow.  Is this what's meant by a tear drop shape?
I agree fully that the string grooves need to be filed in such a way as to not let the string bend over a sharp edge.  I try to round everything that can be rounded, and by adding the thick reinforcements, there is no sharp edge for the string to bend around as it comes onto the belly as my old recurve does.
I'm beginning to think that there is nothing that can be calculated/measured to GUARANTEE that a bow can take FF except to build some and run durability tests.  Although the hint on using phenolic may be the magic bullet that makes for a guarantee.  
Boy, would this be a good discussion topic for a seminar at Compton's or K'zoo or some such place.

[scrub-buster]

Is it just about stretch, or cutting through the tips?  Could you use FF or other newer material for a selfbow if you build it endless loop with serving around the loops?

[Dave Worden]

You've got me, Scrub.  That's why I'm asking the question.  I only make endless loop strings, loops served with dacron, not mono and B-50.  It's worked on any bow I've built, but then it's B-50, it should work!  I still don't know if I could put a low stretch sting on those bows.  The tips are pretty darn thick and tear drop shaped, but there's no phenolic.  Still looking for the definitive answer to what it takes to be able to use FF.  Though, once again, that definitive answer may be "use phenolic", I still don't have an explanation, just another rule to follow.