Making a Fiberglass Laminated Bow

By Sam Harper

Where were we? Oh yeah, we just did the glue up. Now we have to take it out of the oven and cut it out.

Roughing it out

I'll bet you thought "roughing out" was just something people did to selfbows. Nope, it happens with fiberglass bows, too. Maybe they call it something different, though. I don't know.

Anywho, unclamp it and make sure it isn't stuck to the form. Then put it back on the form and mark where you're going to cut the ends. I'm going to make a 64" bow, so I'll make my mark at 66". Then I'll cut my nocks one inch from both ends, giving me 64" nock to nock.

Once I have those ends marked, then I need to make sure my tips are going to be aligned. There are a variety of ways to draw a straight line down the back of a curved bow. I'll just tell you a few of them.

One way is to use one of those cool lazer doohickies they use to line pictures up on the wall. Stand the bow up against the wall and shine a lazer line on the back. Then trace it.

Another way that is kind of similar is to use the shadow cast by the corner of a building or something. The problem with this method is that the line isn't sharp enough in my opinion.

Another way is to sand one edge of the bow completely flat. Then lay the bow down on its side on a flat surface. Take a block of wood that, when you lay it down beside the bow, comes to the center of the handle. In other words, it's half as thick as the bow is wide. Put that block of wood against the limb on one end and move it all along the back of the bow with a pencil pushed against it.

Another way is to lay a string across the bow from end to end and hang weights off the ends. Then shine a light on it directly overhead. The string will cast a shadow on the back that is perfectly straight, and perfectly aligned.

As for me, I use a template. But to use a template, I still need to do something to make sure the tips are going to be aligned. I mark the center of the handle, and use the string-and-weights method to line the tips up. I adjust the placement of the string until it lines up through the center of the handle. Then I mark each end of the string. When I place my template on the bow (which has a center line through it), I line it up with the mark on the center of the handle, and the mark on the ends of the bow. Then I trace it.

Now I go to my friend's house and use, not his 12" band saw, but my own 14" band saw. You see, I don't have room for it at my apartment. My philosophy teacher, wonderful man that he is, gave me a 14" band saw. He used to make custom furniture, but he doesn't anymore, so he just gave it to me.

Remember that fiberglass destroys bandsaw blades. So just use one blade for cutting glass so you don't ruin your other ones.

After I cut it out, I use the belt sander to sand to the lines. Then comes the fun part--taking the masking tape off. Let's look at the cool part.

Isn't that neat? As you can see, though, the center of the splice isn't the same as the center of the limb. I guess I need to work on that. You see, my zebra wood warped on me back when I glued the splice up in the hotbox, so that made it almost impossible to keep everything lined up. I guess one solution might've been to use lams wider than 1.5". Then I could've sanded them down to straighten out any warpage. You don't have this problem with straight 45 degree splices.

The warpage caused a worse problem, though.

Do you see that? Look at the top. That's all glue up there. The only way to fix it is to narrow the limbs, and that will weaken the bow. It could've been avoided by making wider lams or by doing a better job of getting everything to line up. For example, using guides on the sides of my form would've helped. That's okay, though. Narrowing the limbs will fix that other problem of the splice not being lined up. Isn't that convenient?

Anyway, let's worry about that later. Right now, we want to glue on overlays.

Gluing on overlays

Before you glue on the overlays, you need to sand the tips...

...and the back of the handles.

I say handles with an s because I'm making two bows instead of one. It's ironic. The other bow lamination isn't spliced. It's just zebra wood all the way through, and yet it didn't have the same problem with warping and glue where wood should be.

I use my handy dandy pneumatic drum sander with a 120 grit sanding sleeve to sand.

The back-of-the-handle overlays must not be longer than the fades. If they are, they will have to bend, and if they bend, they could lift up, being under tensil forces. I make mine 12 inches.

The tricky part is clamping them to the back of the handle, because how are you going to get c-clamps on your curved fades? I solve that problem by setting the bow face down on a board, and putting the clamps on the board.

See that piece of walnut under there? It's a problem solver.

I also use a piece of rubber and aluminum for pressure strips. I use Smooth-on, wrap the handle in saran wrap, clamp it, and put it in the hotbox for four hours. I leave the lid ever so slightly cracked so that it doesn't get quite as hot as it did before. I don't know if it matters or not, but I figure it's less likely to delaminate that way.

Oh, and I also glue the tip overlays on there. A lot of people who shoot fiberglass bows like to use fastflight strings. Fastflight strings put a lot more stress on the tip overlays than B-50 Dacron, so you can't use them with just any tip overlay. If you want to use fastflight, then you should use phenolic, micarta, or something like antler or horn for your tip overlays. If you use wood, you shouldn't use fastflight. I'm using wood for the build-along bow, and some phenolic on the other one that my friend gave me--the one who also lets me keep my bandsaw at his house. He's a great guy!

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