A friend needed a quick prop for a painting, so I made this Roman-style bow by heat-bending 1" PVC pipe. Please note that while you can use the same techniques to make a fully functional bow, this one is decorative only. For that reason it might also be a good toy for martially-inclined kids or cosplay.
You will be using heat in this project, so please be careful. Wear heatproof gloves or at very least have a supply of pot holders handy. Also, make sure the room is well ventilated.
Schedule 40 1-inch PVC pipe, 50 inches long
paint, tape, etc to decorate
at least 2 strong clamps
Step 1: Mark Out the Limbs
Mark out the centre of the pipe, then decide how large you would like the handle. I marked 4" on either side of the centre point. Then mark out your siyahs (bow tips). I wanted fairly large, 8" each in from the ends.
Step 2: Flatten the Limbs
This is probably the trickiest part of the project, since you will be heating a fairly large area of the pipe. With a heat gun, start evenly warming the length of one limb, that is from the edge of the handle mark to the very end. It is important to work carefully and evenly, moving the gun continually and rotating the pipe. It may take some time for the pipe to heat enough to be pliable, it depends on the wattage of your heat gun. When the pipe starts to droop under its own weight it's about ready, but don't worry if you mess it up the first time, you can always start again...
Place the heated pipe in your vice. I used a simple board along the top of the table, using the edge of the table as a guide for keeping the limb straight. Clamp it down (an assistant holding the pipe is a huge help here). It looks more realistic if there is a slight taper, i.e. the pipe is thinner at the end than the middle.
If you can't squash it enough, you will have to reheat it. As you do, you will notice the PVC returns to its original round shape, which is something to be aware of inlater.
Step 3: Flatten the Siyahs
The siyahs are the stiffened bow tips of an old-style composite bow. Flatten them to be at right angles to the plane of the limb. Just reheat the tip of the bow down to your 8" marking until it pops back into round, then place back in the vice.
Once they are set, carefully reheat the PVC at the point where the siyah meets the limb and bend slightly.
Step 4: Shape the Siyahs
Creativity time! With the hacksaw, shape your siyahs any way you like. You can also (it looks very nice) introduce a slight curve into the siyahs themselves by heating GENTLY and applying pressure. You don't want to overheat or else you risk them popping back into the round, which is a pain to fix. Trust me. I know.
Step 5: Shape and Finish the Bow
Now for the fun bit. Shape the bow as you please. I found it easiest to bend the handle first, because then I could work on each limb and keep it symmetrical. I wasn't happy with the angle of the siyahs so I did that again. Lastly, I put the final big curve in the limbs.
Again, you do NOT want to overheat the PVC at this point or you risk undoing your hard work. If you overheat the PVC will try to become a regular piece of pipe again. Warm it until it's hot to the touch, then try bending it. I used a large saucepan as a form. Another thing I did was cut and flatten a waste piece of piping and practice bending with that until I got confident. Be patient and you will get there.
As this was a quick prop, I didn't put too much effort into decorating, as you can see. With some more sophisticated painting and maybe some leather bindings, it could look really nice.
If you want more details about the bending technique, I highly recommend the books and videos by Nick Tomihama, the Backyard Bowyer.