Changing paradigms

[Roy from Pa]

Looking good Pat.

[Buemaker]

Can’t wait to see it finished. I have used a very thin rawhide from Reindeer and one time I found a couple of air pockets after it was dry. I filled a syringe with thin hide glue and injected glue through the rawhide and gave it a massage, worked fine. Kept the syringe in warm water.

[Mad Max]

 

[Kirkll]

What kind of glue did you use for the snew and rawhide backing Pat?  That is quite a process you are doing there….

 Cleanest shop I’ve ever seen too. I need to call my interior decorator to pick out curtains now.  Kirk

[Buggs]

Thats a lot of physical mass being added to the bow. Have you ever weighed a bow, before and after the sinew, glue and rawhide are applied?

[Bryan Adolphe]

 That’s a very cool process Pat great job!

[Longcruise]

Thats a lot of physical mass being added to the bow. Have you ever weighed a bow, before and after the sinew, glue and rawhide are applied?

According to Tim Baker, sinew is the only backing that will actually add to the bows performance. 

Not something that I personally know anything about. 😌

[Mad Max]

Not that much weight added 

[Pat B]

Sinew and hide glue do weigh more than wood but the elastic properties of the combo helps to negate that extra weight. Sinew, unlike FG stretches and recovers which gives that elastic property that imparts the better performance.

[Mad Max]

How many # of draw weight will it add?
How many # would the bow be without the sinew?

[Buggs]

FG stretches and recovers. Maybe not as much as sinew, but if it did not, there would be thousands of exploded bows  and a bunch of maimed archers.

[Pat B]

Mark, I'm shooting for about 45#. The sinew could add 10# so if it does I'll tiller it back down to a usable weight.
 Phil, obviously I don't know much about FG but I guess it would have to stretch and recover some or else, like you said it could be trouble.
 I checked the bow this morning and the tips have raised back up off the blocks...



...and here is the rawhide covering the sinew...

[mmattockx]

FG stretches and recovers.

This is correct. All materials deflect under load and then return to their original shape when the load is removed. This happens until the load exceeds their yield/failure limit and permanent deformation or failure occurs. The differences are how stiff the material is. If we take a good bow hardwood like hard maple as the baseline, sinew is about half the stiffness and fibreglass is about 3x the stiffness. This is why it's harder to see the stretch of FG as compared to sinew, it just deflects much less for any given load.


Mark

[Pat B]

Thanks, Mark. That's helpful to know. 

[Kirkll]

I think it’s cool as hell you guys have so much fun with these old school self bow methods. It’s gotta be pretty satisfying when one comes together nicely, and holds up over time. Hat’s off to you guys!   

[Pat B]

February 16 will be 2 weeks since I added the last sinew and rawhide backing so then or sometimes shortly after that I will work on bracing the bow.   

[Mad Max]

First brace on a glass bow with masking tape, the belly side shows wrinkles in the tape. 

[Pat B]

Compression effects on the tape?

[Roy from Pa]

Compression effects on the tape?

Pat, I think he is off his meds again:)

[mmattockx]

Compression effects on the tape?

Yep.


Mark