Tanned snake bow backing

[bigcountry]

Ok, I am almost finished with my son's osage bow.  Its only 36" long and pulls 8lbs at 12".  I might take off another pound or two.

But here's my thought.  Kids are rough on things.  My wife is worried its going to break.  So I was going to sinew it.  But that adds wieght and limbs are very thin now.  So I thought, ok, I would raw hide it.  But then I thoguht of something.  

Is tanned rattlesnake strong?  Or strong enough for protection on the back of of a kids bow?

I was snake skin it anyway just to make it like his dads,(me), but figured this way I could kill two birds with one stone.

[Pat B]

I don't like tanned skins for bow backing because it is like a sponge that will soak up moisture.  The osage should be tough enough that he won't break it. If you feel a backing is necessary I would use rawhide, silk or linen.

[bigcountry]

Silk, sounds like the ticket.  SawFlier brought that up too.  Any particular kinds of silk?  Just go to a craft store and get silk?

[Pat B]

Thrift stores usually have ladies silk shirts or even neck ties that can be used as a source of silk. You might get a nice pattern too.
   You should be able to find silk or linen at cloth stores.

[bigcountry]

Been doing some reading tonight about silk in the TBB, and they say it should be put on under pressure and kept to dry.

All I want it for, is to keep the bow from breaking and hunting my boy.  Not increase performance.  

Is this tension method really necassary?

[Pat B]

You aren't going to get any extra performance from silk anyway. I've backed bows with silk before and didn't put it under tension first. The material(silk, linen and even brown paper bag)when set in glue becomes very strong; like with glass fibers and resin. Any of them will help to hold the bow together. I really don't think you need to back it anyway unless the bow's back has issues. Osage is very strong and if the back is in good shape it can take a lot of abuse before breaking. I've been building bows for 25 years and never had an osage bow fail in tension...and at 8# the only way it is going to break is if it is drawn way too far unless the back has issues.

[bigcountry]

Well, I must be living my life wrong.  Because with a perfect tiller, she broke.  Tension break on the back where I heated her and bent the limb.

I made the mistake of trying to tiller real thin on one side and I guess it put too much tension on to small a piece on the back.  It was at 10lbs at 12" when it broke.  I had what I considered a perfect tiller.  I used my block wood gizmo with the pencil and showed both limbs perfect shaped.  So I was in teh middle of sanding down teh belly trying to get the wieght to 8lbs at 12", and wierdly I developed a hinge out of nowhere.  I thought I heard a tick.  So I worked around the hinge, but it blew up.

Guess my wifes intuition is right.

 
 

[Roy Steele]

First of all at 8 pounds your O'sa ge bows not likely to break.Unless the backs rings are vialated Besides if your tillered right your childs not going to hurt it by putting arrows down range.I have 2 boys beleive me O'saga will hold up.
    BIG COUNTRY your bow may have broke where you heated the limb because you dryed it out to much at that spot.

[bigcountry]

Originally posted by Roy Steele:

    BIG COUNTRY your bow may have broke where you heated the limb because you dryed it out to much at that spot. [/QB]

Everybody else has such great luck with heat guns.  I never do.  Looking back, what I should have done is keep the limb more thick than wide, heated it to move sideways, then reduced the limb thickness.  

When I heated it and put it in a form, the limb wanted to curl up and over instead of purely sideways.

[Pat B]

It looks like the limb was not scraped evenly. One side looks way thinner than the other.
I use oil on wood when I use a heat gun to prevent scorching. I very rarely use the heat gun on the back and if I do I let it rest for 4 or 5 days to rehydrate. A dry, brittle back will break. Heat the belly and sides only.
   I think you are trying to over think this. Keep it simple. Your limb cross section should be rectangular. If it bends sideways clamp the handle to the form, heat the wood a bit and slowly line the limbs up clamping as you go out to the tips. Let it rest and cool completely before removing it from the form.

[bigcountry]

Yea, I scraped it uneven to keep it from bending back.  Big mistake.  I heard you can sometimes tiller a limb to bend to one side.  Oh well, live and learn I guess.

I am rather embarrassed about it.  Second bow broke in a month from stupid mistakes.

[Pat B]

I broke two bows in a row last year from stupid mistakes and they were the first breaks in a long time. We all break bows if we are making them. I keep most of my broken bows to study later. They can teach you a lot...once you calm down from the break.
   You can tiller some twist out of a limb but it would less extreme than what you did. If it takes more than a few scrapes then it it probably time for heat. Twist in a wood bow isn't like twist in a glass bow. Twisted wood bows can shoot for years and many arrows and still be ready for more.
   There are 2 kinds of twist. One is natural prop twist that is a result of a tree with a spiral growth habit. Then there is twist caused by uneven limb thickness. If that can cause twist, you can also reverse twist by making one side of your limb stronger than the other...but with limits.

[bigcountry]

Well Pat, I guess the bright side of this, is I bet I never forget this lesson.  Thanks again for all your advise.