making fiberglass lams

[Bradford]

I remember reading on how to make your own fiberglass lam's.. but can not seem to find the thread.  Not sure if it is this site or the other forum that fell apart about a year ago.  So if anyone has any info on making your own fiberglass laminations, I would love to chat.  Really want to try to make my own.

[Living_waters]

I havent tried it yet but a guy gave me this site  http://www.fiberglasssupply.com  and said they have a 6oz unidirectional fiber glass tape he uses with a cheap marine grade epoxy.  He has used it on the back and belly and averages about 10lb on the back increase. He said he has also used their carbon fiber.
Looks interesting.

[mater]

I just finished a bow with 6oz. cloth on back and belly and it broke first pull.  It was 64" and about 50#.I dont make many wood bows so it could be me. But its not a cure for breakage.  Mark

[Pat B]

The glass back and/or belly could contribute to bow breakage or fretting. A well made selfbow doesn't need a backing for protection or to give it more zip. If a stave does have back issues and a backing is necessary linen, silk or rawhide will add that protection and a sinew backing will give it the extra zip.
  If you are gonna make a wood bow, make a wood bow! If you are gonna make a glass lam bow then make a glass lam bow. Using the correct design and materials for the style of bow you want to build is the way to go. You can't make a silk purse from a sows ear no matter what you back it with.

[Living_waters]

I agree but the guy I was talking to was using the tape on a laminated bow not a self bow. I have heard of fiberglass cloth crushing most woods on self bows.
I believe I was watching a video on you tube where a guy was making lams on a sheet of glass he was covering the glass with paste wax or Vaseline first to prevent sticking and then laying down a coat of epoxy then laying the cloth soaked in epoxy down and rolling it with a small roller. He said if you didn't put epoxy down first on the glass it would leave bubbles.
In theory the longitudinal or unidirectional tape and epoxy would be the same as a lam of Gordons. It says one layer of tape wets out .0128    
We cant clip the wings of the ones that are brave enough to experiment, where would we be.

[hova]

but if you lined it right you could make a silk purse that looks like a pigs ear...


just stopping by to be contradictory...

-hov

[mater]

I should say mine was five laminations of wood. It shows that 6oz. cloth isnt strong enough for a laminated bow. Maybe two layers?

[Pat B]

Mater, where did your bow break. Was it a belly failure or a backing failure?  The inside lams don't have to take much stress. They are basically neutral. The back get pulled(tension) and the belly gets pushed(compression).
  With a multi lam bow if you use a good backing wood like hickory or bamboo(even maple, ash or elm) and a good compression strong belly wood like osage, yew or ipe the center lamns have very little effect on the bow except for their physical weight. They are mainly there for appearance. You can pre-stress each layer as you glue them up seperately and get some positive effect but depending on the woods used and their physical weight it might be a mute point.

[mater]

The tension side broke. It was hickory all the way through. There was a small knot on the back lam, I thought it was to small to worry about. The bow had alot of reflex to it. I was just experimenting. Not a los, but a lesson.

[Living_waters]

May have just been over stressed and no amount of strengthening the back would have saved it. Glass won't make them indestructible. I had a Martin hunter break and it was the glass that gave up on it.
Pat b is right a well designed all wood bow will work...even work well. I prefer an all wood bow but I have to admit, I won't let myself get to dogmatic about it because all bows are a work of art and worth their own place of respect.

[T L]

For what its worth , I made a hickory bow and it came out a little light in pull, so I backed it with regular fiberglass and marine resin.
  It added 10lbs to draw wieght and started to de lam after ten arrows, I think the general purpose resin is too brittle.
  It was just an experiment, i was able to pull the glass off, and backed the bow with another piece of hickory and it still is shooting fine.  TL

[Living_waters]

Yeah the polyester resin is not that strong in adhesion. I did an unofficial test of bonding strength between materials woods. Used tb3, polyester resin, 5 min epoxy, and some mast epoxy resin I had left over from a boat build. The 5 min and polyester were a joke but with out a way of measuring the force the tb3 and epoxy felt really close, intact both had the same wood fracture with the glue joint still intact.

[Bradford]

Glass as a form might work.  The one thread I saw way back when, the guy used a metal plate with metal strips for the height and form.. so saw a 12"x72" piece of metal with 3"x72"x.050.  Then once he epoxy'd and glassed, he put another piece of metal on top.  But, I can not remember what he used for resin.. and how he attached the metal.  Would really like to make my own lam's.. just adds to "Hey.. I built it from scratch".

Open to all ideas..