A Faw Questions about Laminated Fiberglass bows

[arachnid]

Hello, I`m new to TradGang.
My name is Dor, I`m from Israel. I Build wood bows (selfbow and laminated) for about 4 years and I want to give fiberglass laminated bows a shot (and forgive me any PA member...). I have a few questions:

1) I have very limited power tools and I live in an apartement. So, Do I HAVE to use tapered lams or can I make all of the lams parallel (I can just saw a board to lams at a local carpentr`s place. He doesn`t have a lam grinder..).

2) Since I have to order fiberglass online from europe (from the US it`s a pricy shipping) I was wondering if I can use fiberglass cloth. I thought I`ll glue the wood lams on the form first, and then add the FG cloth on the back and belly (It might even give me time to tiller before adding the glass).

3) If I CAN use fiberglass cloth, do I have to use uni-directional or does the woven kind works as well?
And, is there any difference in preformance between FG cloth and bow-making FG?

4) Do I need to concern about grain orientation it the wood lams (since the FG is doing most of the work)?

5) What are the wood lams for (besides looking good and seperating the fiberglass lams)?

well, that`s it for now...
Thanks,
Dor

[KenH]

Hi Dor;

1.  Many glass-lam bows can be made with parallel lams, I make my Scythian bows and other designs that way.

2.  Glass cloth is only good for backing a wood or wood-lam bow to prevent splinter rise.
 
2A.  You can glue up the wood lams first, then glue the glass on back and belly.  My Scythian design is so radically curved, and I use an open top form, not a pressure hose, that I have to do it that way.

4. You don't need to worry about lam grain in a glass-lam bow as it's major purpose is to separate the glass lams which provide 88% of the power.  I've made very successful glass lam bows with cheap pine lams.

[arachnid]

Thanks Ken.
Can I make R/D longbows or recurves with parallel lams only?

As I understand, the tapered lams are there to create an even limb curve. What do I nee to take into consideration when using parallel lams?

And, is there any difference in proformence between tapered and parallel lam bows?

Sorry for all of the questions....these are just things I need to know and haven`t found any info...

Dor

[wood carver 2]

If you have access to a jointer and a table saw or band saw, here's an easy way to make tapered core lams.
Start with a board as thick as the width of the bow you're making. It should be at least an inch or so wide, and 1/2 the length of the finished bow. So if you are making a 68" long by 1 3/8" wide bow, you will need a piece 35" long by 1 3/8" by at least 1".
With a pencil, divide it into 3 sections. Make your marks visible on the 1 3/8" side. Now, set the jointer for a light cut and plane to the first mark. Stop there and plane again from the beginning to the second mark. Stop, and plane from the beginning to the end. Your board is now tapered. If you need more of a taper, you can do it again. Now you can go to the saw and set it to cut off the tapered part. The taper should be on the outside of the blade and it becomes an offcut. Repeat for your second lam.
Of course, this is something that you should not do unless you are very comfortable using these tools. A jointer can be a nasty piece of equipment if you make a mistake.
I also use a stationary belt sander the same way to taper lams. Mark the wood, sand to the line, sand to the next line, sand through. I use a square block of wood to push the lam against the sander. This takes longer, but it works well and is a safer way than jointing.
This takes a long time to explain. If you were here, I could show you in not time.
Dave.

[wood carver 2]

Oh, and the reason I said 35" long is so you can cut a scarf joint in the two ends to join the lams.
Dave.

[Robertfishes]

could you buy your tapers from the same place you buy your Fiberglass pieces? when choosing bow lams..In my opinion grain orientation does matter, I use edge grain in my tapers and parallels. the exception is when I use very thin (0.025") veneers under clear glass, most are flat cut. I have not built a parallel bow, I use either .002 or .003 per inch total taper in my limbs.

[Kauz]

Tapering could be done with a handplane in a similar way to Dave's method, preferably a long plane, like a jointer or jack plane. With edge grain, this would work best. You should sand the planed surfaces with 80 grit sandpaper for better gluing.

[KenH]

Yes you can make R/D and recurves with parallel lams. I made these two bows, and others with parallel lams.  The upper bow is 44" n-t-n, the
Scythian style on the bottom is 48" n-t-n.  Both are 1.5" wide at the handle fades and taper in width out to the tips.

  [/url] [/IMG]

I made them using this type of simple form cut from a 2x10
  [/url] [/IMG]
 
You don't NEED tapered lams. Tapered lams may be slightly better efficiency wise -- but I've not seen anyone   prove it by making two identical-except-for-taper bows and putting them through rigorous testing.

[LittleBen]

Since you are going to need to order fiberglass laminations by mail anyway, I would suggest finding somewhere that can send you good quality lams too. They aren't that expensive, at least here in the U.S. they can be had for about $15-20/lamination. You're going to pay for shipping on the fiberglass anyway, I'd order it all together. That way you know you've got the right stuff and your time won't be wasted.

[arachnid]

Ok, thanks a lot for the info so far.
Now, lets move on to wood selection and glue.

1) Are there recomended woods to use or any will do the job? The easiest lumber I can get are- white oak, ipe, maple, bamboo flooring. I might be able to get walnut.

2)I've seen bows made with 2 wood lams (one parallel and one tapered) and with 3 lams. What's the difference?

3) The online store I will get the FG from has something the call "carbon core" or something similar. Here's a link:
   https://shop.bearpaw-products.com/WebshopB2C/Bearpaw_Stabil_Core/P-161/1  

Anyone heard/used it? What is it used for?

4) Can I use any king of epoxy? I can get 2 ton epoxy (the double syring kind), polyester resin, or something  else which is a local product.
Thanks in advance...
Dor

[arachnid]

Ben, unfortunately Bearpaw doesn't sell wood laminations (or at least I haven't found any at there online store).

[takefive]

Hi Dor-
I'm on PA, too.  I mostly make wood or wood laminated bows, but I've made two FG bows buying the glass and lams from Bingham Projects.  I got the plans for the form and a follow along DVD from them, too.  They carry Smooth On epoxy, which I'd guess is the choice of most glass bow guys on here.  Unless their shipping cost to Israel is too prohibitive, they are a great choice for your first FG bow.
Here's a build along from Sam Harper that helped me alot.  It was good to know that I could use all the C clamps that I've amassed for hickory or bamboo backed wooden bow glue ups.

 http://poorfolkbows.com/glass1.htm

Another very helpful one from KennyM:

 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=001165;p=1

[Buemaker]

You can get wood lams, glass and epoxy from this guy in Germany.
 http://rudiweick.de/bogenbaumaterial/