# Laminated fiberglass bow building question.



## jgpk (Sep 6, 2011)

I am soon to attempt a fiberglass laminated bow. i made the form, it will be a straight end hill style longbow. i have made quite a few wood bows so i am familiar with that process however i have several questions if anybody knows the answer i would really appreciate the help. 

First i want to cut my own laminations. i have a nice bandsaw that cuts decent with a board used as a guide. i also rigged an adjustable table on an old belt sander to sand laminations and am able to sand very good laminations. ok my question is it necessary to use tappered laminations? i have heard that you can use parallel laminations for the whole bow and this makes sense as the taper on the limbs will be cut in from the sides. does this affect performance? i am not looking for the worlds fastest longbow but rather a durable one. 

ok my second question is why do bow makers use so many laminations? i have seen kits that the whole wood portion of the bow is cut from a single piece of hickory and the glass is glued on. i assumed this is for mass production and dependable results. it stands to reason that if a bow made from 4 laminations at x dimentions will make a bow of z draw weight every time. however why would it not work to take a single piece of say quarter inch limb material, glue on a riser and then glass this. is a lamination strip required on the belly.

finally i planned to use black walnut for the entire bow. will this work? i selected a piece that i would make a wood bow out of so i know its a good peice of wood. would i be better off using maple or bamboo in the core section?

ok i know thats a lot of questions but i appreciate all the help i can get. i think i have a good feel for the rest of the process and, as i have a small knife making shop, the required equipment. 

thanks


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## Hunterdale (Nov 28, 2009)

You might ask this question over at The Leatherwall on Bowsite. A fair amount of bowyers over there.


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## Stash (Jun 1, 2002)

I'm not a bowyer, but I have some input.

Tapered laminations may reduce splintering along the limb edges but parallel laminations are almost as good, and a lot easier to make.

As you well know, wood is inconsistent. The more laminations you have, the more likely you will have 2 sections of wood that will have similar characteristics. Also, more and thinner laminations will reduce warpage. 

Again, wood is inconsistent, so you can't guarantee X thickness will produce Y draw weight. With practice you can get close, but the type of wood, length and width are also factors, not just thickness. Your first few bows will probably be complete guesses.

I can't say about the walnut, but maple is the wood of choice for limbs because it is light and springy. Perhaps walnut will be too heavy for laminations? Maybe best to just have it in the handle area.


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## timduvall (Mar 18, 2008)

walnut is a very good wood to use in the limbs...taper laminations help increase speed because the less material at the limb tips means the limb tips can recover faster which means more speed. The lighter the tips, the less handshock and greater speeds you will have..within reason..you don't want 'whippy' tips...but yes, an all parallel limb will work...it will just hurt the efficiency of the bow.

more laminations in the limbs help with the stability of the bow. the more laminations you have the greater the stability..think actionwood...those risers are practically bombproof.

the weight of fiberglass bows comes from the thickness of the limbs...a given thickness will produce a given weight provided you keep some parameters constant (i.e. ratio of glass to wood core)...what i mean is lets say that you your form gives #40 bow with a limb thickness of 0.25" using 0.040 glass...if you go to 0.050 glass and decrease your wood core to keep the 0.25"...your weight will be different because you changed your glass to core ratio..going from an all parallel to a tapered core will also change your weight because you are making the limb profile different...lots of variables to bow design/building...good luck...its a blast.


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## Stash (Jun 1, 2002)

Re: "tapered laminations" 

I think he was asking the value of actually making the laminations tapered not just the limbs. The limb tip weight would be the same whether the laminations taper or not.


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## vth0kie12 (Mar 5, 2007)

you get you bow wight from measuring the lam stack at the but end (handle). if you are going to use onl parallels you may needs to adjust yor stack to get your wieght (the more taper you have the more your tips are going to move which helps with speed, but you can get your tips to wippy and that will cause your bow to stack bad at longer draw lenghts) . you can make the bow from parrallels, but from waht i gather its better to use tapers. you get better preformance and it have less hand shock. 

the few bow i have built i have used tapers in them all. binghams have some good plans and dvds to help if you need them. 

i have never used walnut as a lam, but i have heard it is a good core wood. nowi have used it for a riser block on a kids bow and it has held up fine, but i have read that walnut is a very unstable wood and you really need laminate some sort of accent strip in it.

you might want to check out tradgang.com, those guys over there can help yo a lot more than my self 

i will say that if you are designing your own bow it can get expensive very quick, the first few are just a guessing game on what the weight is going to come out. i designed a reflex/ deflex longbow a few months ago and my secong bow missed my lbs by 8 lbs, and that after i cut the limbs down 4 inches to stackt he lbs. 

as far a the amount of parallels/ taper; you get alot of your glue lines give you a lot of your strenght. i would not suggest using one lam.


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## vth0kie12 (Mar 5, 2007)

i should have read timduvall post, he hit the nail on the head


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## kerrye (Sep 1, 2010)

Bought my first laminated recurve in the late fifties from a guy in Springdale, Ark. who started building his own bows after he had three commercial bows twist out and delaminate. He said he just finished tearing the last one completely apart to see how it was made and started making bows. He said: "after I built about a hundred of them, I made a pretty good bow".


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