Aurora’s Bow – A Compact Two Piece PVC and Fiberglass Tent Rod Takedown Bow

In my last post, I wrote about the making of the Imperial Ranger takedown bow, a large, heavy 3 piece bow meant to emulate a warbow that was small enough to fit inside a backpack. At the same time, I was also making the one which will be detailed in this post, which, in many ways, is the total opposite. Whereas the Imperial Ranger bow was large and heavy, this one was designed to be as small and light as possible. The Imperial Ranger was also complex (although not necessarily on purpose), whereas this one was designed to be straightforward and simple. Yet, they both function as takedown bows able to fit in small spaces, and despite the small size, this one packs a punch – 50# of draw weight when pulled back to my draw length of 32″.

So what do you need to do to make a bow like this?

Here’s the materials:

One piece of 1/2″ Sch 40 white PVC pipe (I used a piece 36″ long)
One length of 3/4″ Sch 40 white PVC pipe for the handle (I used a piece 7″ long)
A flat hardwood coat hanger (I used one made of cherry; for strength, make sure the grain of the wood is running horizontally when the hanger is held in its hanging position)
Fiberglass tent poles (I used four, two per limb, each about 15″ long and 4 mm in diameter)
550 paracord for the string (or your bowstring material of choice)
Heat gun
Gloves (for handling hot PVC)
Flattening jig (to flatten the PVC pipe once hot; see info below for more info)
PVC cement (optional)
Sandpaper
Saw
Spray paint and clear coat varnish (optional)
Leather for arrow rest and arrow strike plate (optional)

If you already have the tools (heat gun, saw, etc), this bow can be made cheaply (for under ten dollars – the main costs will be for PVC, paint, a can of Great stuff foam – the hanger and tent poles you may be able to find around the house or by repurposing stuff you find used). This bow is not very complex to make, though if you’ve never made a PVC bow before, I highly suggest you make a few prior to attempting this one. Or, check of the 3 piece PVC fiberglass rod bow post with the associated video or the updated Fourth of July bow for a hybrid PVC/fiberglass bow you can make in probably less than an hour.

PVC is a forgiving material. Even so, practice does make the process easier, and making PVC takedown bows is more complex than one piece bows. I highly recommend you check out videos on youtube such as the Backyard Bowyer channel by Nicholas Tomihama. Though plenty of folks have uploaded videos of their creations, he, in particular, has a huge variety of tutorials (meant for both beginners and advanced PVC bowyers) to walk you through making PVC bows as well as the equipment you’ll need to make one, such as the flattening jig I mentioned above – easy to make once you’ve seen it, though more difficult to explain in isolation.

I’m going to pick up after the PVC pipe has already been flattened (in this case, I flattened the pipe in such a way that the handle was thicker and gave the limbs a gradual taper). I next cut off the ends (~8″) of the wooden coat hanger to make wooden tips for the bow (called siyahs in archery terminology). Wood is lighter than PVC, and the lighter ends allow the bow tips to move faster, theoretically increasing the velocity imparted to the arrow. In order to attach the wooden tips to the PVC, the ends of the PVC pipe need to be heated until they swell back up again. Then the wooden tips can be inserted inside (about 2″ should do) while the PVC is still hot. When the PVC cools, it will shrink, forming a tight grip on the wooden siyahs. It is important at this step to make sure the nocks line up.

Although I added more heat to bend the limbs forward just proximal to where the siyahs were inserted, thus reflexing the bow limbs (adding a bit more spring and draw weight), you don’t need to do that. You can create a bow that has a simpler longbow shape as opposed to the one I ended up with.

At this point, after everything cools, you can string the bow and check its profile. There should be fairly evenly bending limbs on both sides without major twisting. If one area is bending more than the other, correct it now by gently heating the area until it puffs back out, then use gloved fingers to shape the limb. This part is admittedly finicky and takes me the most time. But it’s always a good idea to try to correct minor issues of limb asymmetry or misalignment now prior to progressing further. For those that make wooden bows, this trial and error process of making the limbs draw as evenly as possible is akin to “tillering.”

When I was finished with this portion, I strung the bow and tested the draw weight – it was about 20-25# at 32″, which was about right for 1/2″ PVC.

Once I was satisfied with the profile, I cut the bow in half at the center. I then heated up the piece of 3/4″ PVC and fitted it over the limb I’d designated as the lower limb. A layer of PVC cement helped secure it in place. I then heated and shaped the other end, making it a bit more of an oval shape in cross section to match the lower limb side. In general, despite what I said above about making the limbs draw as uniform and evenly as possible, one limb may bend slightly more – this is fine. Make that one the upper limb, since the grip is usually in the center of the bow, and the point where the arrow is resting is usually above that, meaning the upper limb needs to bend a little more to compensate for the arrow not being right at center.

Next came the rejoining of the two limbs. This was not my first takedown attempt – I have been fiddling with them for the past six months or so – but still find that they can be persnickety things to get right. Of course, there’s the simple fact that you must make an essentially “broken” bow function as if it were whole again without exploding in your face. But if you take care, make sure the limbs are aligned and the junctions properly reinforced and not at particularly high stress areas, making a functioning and safe bow gets easier with time (though there can still be surprises, as my last post will attest). No, for me, that hardest part is, in some sense, the simplest – once joined, getting the two pieces apart again. It’s taken a lot of fiddling and some consultation from people smarter than I on the interwebs (i.e. youtube and the google plus PVC bow making community) to get it right.

So here’s the secret – heated PVC expands. Cooling PVC shrinks. So the trick to being able to get the 1/2″ limb out of the 3/4″ PVC piece once heated is to heat the end of the 1/2″ PVC limb, stuff it in the cool 3/4″ piece as best you can, then wait. As the 1/2″ PVC limb cools, it will shrink in diameter, allowing you to pull it out again once cool. It sounds simple (and is, once you know the trick), but I’ll be damned if it didn’t take forever on this particular bow to get right. A layer of plumber’s grease on the joints hasn’t hurt, either 🙂

Above is a picture of what the bow looked like when everything was assembled. Then, since I had them lying around, I wondered what would happen if I added some small (4 mm diameter) fiberglass tent pole rods in the limbs. I had a bunch lying around that I’d found somewhere, and since they were about 15 inches long, I figured they could fit easily into the flattened limbs. I was able to fit two in each limb, which I “glued” in place with expanding Great Stuff foam (which comes in a spray can and is used to seal holes around doors and such – a wonder of modern technology that I both admire and curse. Two words – wear gloves. You will be glad.)

Once everything was dry (I let the foam cure for about a week, I think), I reassembled it and tested the draw weight. I was surprised at how much the draw weight had shot up – somewhere in the upper 40s to low 50s – an increase of 20-25# of draw weight just from using the two thin fiberglass rods in each limb.

From there, it was just the finishing touches – a few coats of spray paint and clear coat lacquer, a grip, an arrow rest, and a string with nocking point wound on. The pictures do these details better justice than my descriptions could.

Final specs:

Length nock to nock when strung: 45″
Unstrung length: 47.5″
Length of each limb: 27″ for the lower, 22″ for the upper
Brace height: 4.75″
Draw weight: ~50# at 32″
Speed: varied considerably from 166 fps – 194 fps with the 446 grain arrow I used; I suspect due to inherent inaccuracy in the sound based app I used to test the speed, but after averaging the four values I obtained together, it came to 179.25 fps.

So how does it feel to shoot? Well, it’s small, light, and solid. The brace height is low and is probably more comfortable to shoot with an arm guard on, since the string sometimes snaps the wrist or heel of the hand. Since it’s such a small bow, the angle the string makes with the fingers is fairly acute, so comfort-wise, it could be better. And it stacks a little at the end (meaning the draw weight jumps up the last inch or so), but given the small size, I expected that. I’m surprised it can go back as far as it can without collapsing. All in all, I’m happy with the way it turned out. Given its speed and pull, it goes to show that appearances can be deceiving. It makes a nice little companion to its larger partner bow, the Imperial Ranger takedown.

If that bow was meant for Logan in The Thirteenth Hour, then this one is meant for his partner in crime, Aurora – smaller, lighter, but just as fast, strong, and versatile. And so, ladies and gents, that’s where the bow in the title gets her name. You will see more of Aurora and her bow in the as-of-yet-unnamed sequel to The Thirteenth Hour. So stay tuned! Until then, I leave you with a picture of Aurora from when she last fired a bow in the The Thirteenth Hour.