Lamination formula

[Rocriver]

Hello all. I’m about to build my first laminate bow and I got tons of questions. I’ve built a lot of self bows 20 years ago but never fiberglass. I been reading for days but not found a formula. Is thee one? I mean like lam thickness, glass, tapers, length for target weight?

I’ve Ben shooting and hunting with longbows for 30 years but I want to make a takedown recurve. I need a rugged bow as I’m kind of rough on them. Would like to cut my own veneers if I can. I’m a woodworker and I’ve got a ton of scrap strips about 8’ x 2-3” x 1/4”. Most are cedar but a lot of hickory, hard maple, yellow birch, and ash. Also have a lot of salted wood I’d like to cut veneers from if I got any good ones.

I’m just trying to figure what and how many or how thick of laminations and glass to come in around 50-60 # at 29”? Thanks for any tips and the ones I already got from reading all the great content on this site.

[kennym]

Your stack thickness will depend on bow length, width and a few other things. I don’t make recurved but Binghams Projects has a pretty good chart fit thicknesses  for recurved.

Good luck and enjoy!

[Crooked Stic]

Your first one go with Binghams design
. They have the stacks already figured out. Every design will have a different stack to hit target. And get some Stable core from Kenny for your limbs.

[Flem]

I don't know about Binghams, they don't give all the specs. I was curious one time and called to find out the thickness of glass for one of their stack recommendations, the guy told me it didn't matter!
HUH? glass thickness does not matter, I thought WTF, since when?

[monterey]

Got a similar response way back.  Wanted to know what thickness to use for a certain stack and the answer was "just don't go to extremes".

All the ASL s that built off their LB chart came in pretty much right on.  Course, i didn't go to extremes. 

[Mad Max]

Jim Thorn's "Build your own bow"  I got my plan's for $15.00
Contact  from Facebook

[Crooked Stic]

Flem I have built several bows same stack one .050 glass one .040 glass very little draw weight difference if that is what you mean.

[kennym]

Hey Mike, you mean one bow with all .050 and one with all .040  or a bow with different thicknesses on each side?

[Flem]

Flem I have built several bows same stack one .050 glass one .040 glass very little draw weight difference if that is what you mean.

Actually what I mean is that I am bit miffed when a retailer proffers up a formula, with measurements down to a thousandth of an inch and then when questioned about a component, which is likely the strongest constituent of the formula and will vary the formula by 10 hundredths of an inch, tells you that
"it does not matter"

[monterey]

dang, Flem, I know you realize that total stack is the operative factor and that going to thicker glass would require reducing thickness of other components such as the core lams.

[Flem]

Yes, I do. But those formulas are meant primarily for first time bowyers, who might not know that. If it was me offering guidelines, I would assume the person asking questions would want a complete picture.
What can I say, I'm a hard a$$ when it comes to details!

[monterey]

I get what you are saying and agree.

Another thing they don't mention to the first timer is that the weights are based on getting a full width blank off the form.  Most first timers will lose some to squiggle.

[Mark R]

The details in Bow building make a big difference. JMHO

[Rocriver]

I don’t know how to do Facebook so that’s out. I was just asking as I just want to hunt with a bow I made besides self bows. Want something a little more rugged as the older I get the harder I am on bows.

I just thought that with lams be so precise to thickness and taper, and different woods, and the millions of them built, someone could give me a close idea. Those lams and glue and finishes aren’t to cheap so I’d rather not start at the bottom and experiment.

I know wood varies so it won’t be the same always but within 10 lbs. I’m happy. Got my form hardware and hose finished last night. I’m ready to cut my form shape and assemble. I have a hot box I use to keep woods stable in humid weather but I’m not sure of temp. I’m sure I’ll have to modify it just a bit.

I’ve been thinking on veneers as well. I’ve got all kinds of burl, and spalted wood that I would like to use but I’m not sure if the quality is bow material though? I’ve got some awesome pieces I’ve saved over the years just for this project.

I’ll figure it out eventually. Lol. I’ll update as I go. I’m ready to order materials but I need to call and talk to the folks at three rivers and bing man and see what they recommend first. Another question....will regular store bought wood veneer work? I have found some beautiful wood veneer but not sure of the quality. The veneer stores online have some amazing veneers in case mine isn’t good enough. Thanks for the help.

[Mark R]

For your first time go to kennysarchery.com he has good info on start to finish, and can help with the material and size and draw weight on his design if thats what you want. Different designs will require different stack calcs. to get the right draw weight. As for veneers I would stay at or under .030, its mostly figured in the metric system and will be calc. into the stack, plenty of more info on performance and designs so kiss and go with proven bow design and specs, as for hot box temp I get it up to 160 for 4 hrs. others may differ and hose pressure also. Better yet just go to kennysarchery.com browse and call him if you have questions and everything should work out fine for ya. Being a wood worker you will probly want to make more than one and get sucked in like the rest of us, it will make you happy. Also I have never dealt with Kenny but browsed his website and he has a wealth of good easy to understand info. and is highly regarded on this website.

[Mark R]

Rocriver I see your in sw Wi. Im in the west suburbs of Chicago so not to far away PM if you want, be happy to to talk to ya.

[Mad Max]

Can you post a picture of what you want it to look like un braced?

[Rocriver]

Just standard recurve for shape. I’ve got a lot of fine bows I can use for a pattern and then tweak it a bit somewhere to make it mine. As far as kennysarchery, I checked it out and thanks for the tip. They have all I need at a good price. I’ve got an email in to there now with a few questions.

Another question....will e40 bond with wood stained wood? Oil base probably not without long drying period but what about water base stain? May have to use heat a little to ever get it dry enough? I was just wondering. I’ve got my form built completely except cutting the shape. I checked my hose press over night last night and it only lost 4 lbs in 12 hours at 88psi. Should worked fine for eight hours at 40 or 50 lbs. Thanks again for the tips and help.

[Crooked Stic]

I would find and fix the air hose leak. You dont want it fail with a bow under it. Alcohol (denatured) or leather dyes are best.

[kennym]

" I checked my hose press over night last night and it only lost 4 lbs in 12 hours at 88psi. "

 If that wasn't with heat, you may want to find the leak and fix it.  The heat may let it spit the plug out , that ruins a bow or limb. I know this as I heard it from a friend.... LOL