Making a Fiberglass Laminated Bow

By Sam Harper

Now let's prepare the fiberglass.

Preparing the fiberglass

I actually prepared the fiberglass before I did anything else. It's just that this build along is topical, not chronological, remember? I always prepare the fiberglass as soon as I get it in the mail. You can get fiberglass from Bingham Projects or Three Rivers Archery. I'm sure there are other places, but those are the two I know about. I get mine from Three Rivers Archery (3RA) because (1) it saves on shipping since I get other things from 3RA, too, (2) it's cheaper than Binghams unless you buy in bulk, and (3) they don't give you options like Binghams does. The reason I don't like options is because I don't know enough to choose, and having options stresses me out. I'd rather the choice be made for me. I get it in .05" because that gives me room to tiller if I want to.

Fiberglass is nasty stuff. It is the primary reason I don't make many of these kinds of bows. The splinters are harder, they're invisible, and they're numerous. You have to be very careful with it.

The fiberglass will come smooth on one side and sanded on the other. You want the smooth side to go on the outside, and the sanded side should be the glue side. The first thing I do is lay it all down with the smooth side up. Then I put masking tape over the smooth side.

The top two have masking tape, and the bottom two don't. Sometimes I use blue painters tape, because it's easier to get off later. But this masking tape I found is even easier to get off than the blue tape. Plus, it's easier to see pencil marks on it. You see, the masking tape serves two functions. First, it keeps glue off the fiberglass during glue-up. Second, it provides a surface for drawing your bow outline with a pencil.

Once I have all the fiberglass taped, I find the center mark. They are six feet long, by the way. Remember that I'm making two bows, not just one. That's why I have four pieces. Anyway, I want to leave two of them 6 ft long and cut the other two in half. The half pieces are going to go on the belly, and I cut them in half to ride up the fades. Of course you can design your riser so that the belly fiberglass goes through the riser, in which case you don't need to cut it in half. But I'm cutting mine in half.

Since there's going to be about 5.5" of the riser that won't have fiberglass on it, some of that fiberglass will end up hanging off the end of my form. But my hotbox isn't long enough for that, so I like to cut my fiberglass a wee bit shorter so it doesn't hang off as far. Instead of cutting the fiberglass in half, I cut out about a 4" section from the middle. I find the midpoint, then measure two inches on either side.

There are a variety of ways to cut the fiberglass. One way is with a band saw. There's something you should know about cutting fiberglass with a band saw, though. As soon as the blade hits the glass, you'll see some sparks. That's the blade being ruined. It's necessary, though, unless you plan to whittle your bow out of the glue-up and destroy your pocket knife instead. So just sacrifice one band saw blade and use that one blade for all your fiberglass stuff. That way, you don't destroy all your other blades.

Another way to cut the fiberglass is with a pair of shears. I've got these super cool scissors I can cut a quarter in half with. I cut my fiberglass with those one time. The only problem with cutting fiberglass with shears or super cool scissors is that it causes the fiberglass to splinter a lot near the cut.

I use a Dremel tool with a cut-off blade to cut my fiberglass.

That seems like the easiest way to me.

Once I have the fiberglass taped and cut, I turn it all over. There's going to be dust and stuff on the sanded side, and we don't want that there, because whatever is on there will show up after glue-up. So I take a wet paper towels or something and wipe everything down. Then I let it dry. Make sure there are not cat hairs or anything on your fiberglass or any of your laminations. Don't run your fingers along the sanded side.

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