Perry Reflex

[DC]

Here's link to the explanation of Perry Reflex by Dan Perry. I still have to read it more carefully but I did see that the belly has to be full thickness. I'm not sure exactly what "full thickness" means. I took off the "H" You have to scroll down a bit to find Dan's post.
ttp://leatherwall.bowsite.com/tf/lw/thread2.cfm?forum=23&threadid=188683&category=

[SLIMBOB]

I think his point on full thickness just stresses the point that thin lams won’t produce the same results as a “full” thickness belly.

[PatM]

Interesting that Baker says the belly should be mostly reduced before glue-up and claimed Perry did this but Perry himself  seems to indicate forcing a too thick  belly into reflex is the way to go.

 I do think that both their explanations for Perry reflex are speculative at best but both get to throw their weight into their statement due to  them being considered guru's.

[DC]

 I do think that both their explanations for Perry reflex are speculative at best but both get to throw their weight into their statement due to  them being considered guru's.

Ain't that the truth but then that's the truth for just about everything in this world.
The one thing I know from personal experience is that you get more of that reflex gain while tillering if you use a thicker belly piece. Whether or not it has any influence on the outcome I have no clue. When you make a bunch of bows and they all come within 10fps of each other it's really hard to point a finger at what made one the best. Drives me nuts , but then that's not a drive, that's a short walk. Pu dum dum

[Stick Bender]

 Don are you saying you end up with more reflex in the end after complete tiller using the thicker core or starting reflex ?

[gutpile]

I just taper the belly well before glue up and have had no issues...gut

[DC]

Don are you saying you end up with more reflex in the end after complete tiller using the thicker core or starting reflex ?

I've never done it because I think the set from my poor tillering hides it but yes it seems that way. You take it off the caul after glue up, measure the reflex and start tillering. As you tiller, keep measuring the reflex and you will find that it's increasing. Sometimes quite a bit. I guess if you could do a no set tiller it would keep increasing but I've never managed. l always wind up with some set. I lose the increase and usually more on top of that. Maybe something else happens I dunno

[Stick Bender]

Im just saying to me it seems like all wood bows the more reflex you can start with the better off you are as far as retained reflex so it would seem to me the multi thinner lam could be reflexed farther to start unless heat treated reflexing the core like Marc said but I know with my current self bow I started with 5 1/4 reflexed and probably half that or better at 27" tiller so far so the same principal with less of a degree should apply to Perry flexed bows , like I said I dont no nothing but just thinking out loud !

[DC]

If I'm understanding this at all I think the sign is the increasing reflex. If you don't get any increase in reflex when you start tillering(it may not last ) then you didn't get any Perry into it to start with. The whole thing keys around trapping the compressed back of the core(for lack of a better word) by gluing on the backing while the core is compressed. When the glue cures and you release it the core will try to straighten out. It will straighten until the tension of the back stops it. The two pieces are now in equilibrium. When you start to tiller you are weakening the core(belly). The tension of the back is now stronger and the reflex increases. If it doesn't increase then there was no tension between the two parts and therefor no Perry reflex. Talk me out of it if you can

PS All that said I still don't understand what those trapped tensions do to enhance performance. I don't think it's just increased reflex.

[Stick Bender]

Oh ok but it would seem to me the bow that would hold the most end reflex at the same mass would win the race , (arm chair theory) but what about Marc saying reflexed core works better for him ?

[DC]

There is a limit to how much reflex you can put into a bow. It would be nice to know if you had two bows, both with maximum practical reflex. One Perry and one steamed in. Would the Perry be better?
I know Marc has said he reflexes his bows before glue up. I very much respect Marc and his work. It's one of the reasons I question the whole thing.
My own experience seem to indicate that Perry reflex works but it's a limited sample and I could have just hit something else right.

[ErictheViking]

http://leatherwall.bowsite.com/TF/lw/thread2.cfm?forum=23&threadid=188683&category=

[DC]

I've had that open for a couple of days. I have read it before. I think that's where I got most of my knowledge about it. Time to read it again I think

[SLIMBOB]

So far as I understand it...most of the tension and compression work is taking place on the surface of the back and belly under normal (non Perry reflex bows) conditions. PR causes some of that work to shift closer to the neutral plane (the glue line).  That work is being added to the work the surface wood is doing. That is where the extra kick comes from. So far as I can figure.

[DC]

I just find it hard to grasp how something that is happening at the neutral zone has any effect at the surface. It would seem to me that any internal tensions would cancel each other.