PVC Archery - Test of New Bow

Readers of this blog have seen my previous posts regarding PVC bows. Due to life circumstances in general, coupled with a shoulder injury, I have not done anything with archery in over a year and a half. Today, that changed.



Using some tips I gleaned from Backyard Bowyer's YouTube channel, I quickly constructed this bow today and tested it out.

All in all it worked pretty well; it needs some tweaks and modifications but it clearly IS possible to make a usable 35#-45# draw-weight bow out of standard schedule 40 PVC water pipe for a total materials cost of under $10.

I'm using arrows bought at Wal-Mart for $3 a piece on clearance several years ago. These are good enough but need a little help, too - as the fletching was improperly glued on. I should remove the vanes and glue them on properly. Will discuss that in more detail in a future post.

I used a 55" piece of 3/4" ID Schedule 40 PVC pipe and formed it with a heat gun using methods found on Backyard Bowyer's site and elsewhere online. Flattening the limbs of the bow as he describes definitely helps improve the curve as it is drawn, the force distribution, the overall performance, and keeps the bow from getting a permanent and unwanted bend in the middle. I left the middle 5" of the bow untouched with its original round cross section.

After the pipe cooled, I shaped the ends for attaching the string, which consists of 350 Paracord. This is smaller than the 550 Paracord one normally reads about but works perfectly well on this light a bow. While Paracord is very durable and resists fraying, one definitely wants to put a serving on the string so that the nocking point is thick enough for a standard commercial arrow nock to grip.

I strung the bow for a 6.75" brace height at the center point.

The finished product has a measured draw weight of about 35# at 28 inches of draw.

The arrows in the target shown in the above photo were shot from approximately 30'. No doubt as I build up strength and accuracy much greater distances will be possible. I also plan to use the ballistic chronometer in future tests of PVC bows. Stay tuned ...

A couple notes:
Backyard Bowyer reshapes the middle "grip" section of the bow to improve shooting accuracy. Some folks say you don't need to do this and certainly, it is far easier to leave the handle section alone. This is the configuration I tried today. I noticed some issues with the arrow being deflected somewhat unpredictably when it would sometimes hit the bow and/or my hand. Clearly tapering the handle section and creating an arrow rest should help with this.

Using the technology described above, one can get into archery for about $15-$20 - NOT including the $17 target shown in the photo.

The piece of wire on the target in the bottom photo is for the vibration sensor used with the homemade ballistic chronometer. The sensor, which is actually the piezo buzzer out of an old computer, is duct taped to the lower left-hand side of the target.

Painting PVC Pipe

Just during the past week, someone came to this blog after a google search dealing with "how to paint PVC". This is indeed a good question, so I thought I'd briefly touch on this topic.

Can PVC pipe be painted?
In a word - yes. That said, surface preparation is critical, as it is with painting anything else. There are also some other small but important details to keep in mind when doing this:

1) The surface MUST be clean of all oil, dirt, dampness, etc. or any coating you use won't adhere properly. I typically do this with rubbing alcohol and a clean rag.
2) The surface should be lightly scuffed with steel wool or a very fine grit sandpaper - such as 600 grit or finer. Once you sand or steel wool the pipe, CLEAN it AGAIN with more rubbing alcohol and a clean, lint-free rag.
3) Use a paint designed for PVC. If you don't, you will be disappointed. More on this below.
4) Good spray can technique applies here - use several thin coats rather than one thick one to avoid runs and drips. Also, spray with the can 10" or a foot (30 cm) away from what you are painting. Keep the can moving so you don't build up too much paint on one area. If you haven't done much spray painting, practice on some scrap first before doing your critical work.

Coatings for PVC:

Years ago, I attempted to apply a cammo paint job to an antenna mast I built from PVC pipe for my homemade portable QRP ham rig. I used either Krylon or Rustoleum - I don't remember now. The paint job looked beautiful when freshly done, but proceded to flake off whenever the pipe was bumped. I could scrape the paint off easily with my thumbnail.

Since then, Rustoleum has come out with a primer that works on PVC and some other plastics. Krylon, if I remember right, has come out with a small assortment of colors that work directly on plastics, including PVC - no primer needed. The trouble with the Krylon product is the color selection for their plastic paint is, in my opinion, rather limited.

By using the Rustoleum primer as a basecoat, you can use whatever color you want from their standard line of spray paints. I actually used Krylon's flat "Hunter Green" paint on a 50 caliber blowgun I'm making for a friend. The base coat was Rustoleum primer for PVC. It seems to have worked OK so far. A few accidents here in the lab while handling the pipe don't appear to have caused damage. See the photos for the products used as well as the blowgun.




Caveats:

1) I have not, to date, subjected any of these painted surfaces to severe, real-world testing yet. What I can say is that casual handling and occasional droppage against other objects hasn't apparently caused chipping or scratching. So compared to the antenna mast described earlier this IS a huge improvement.

2) ANY time one applies a solvent-based coating to PVC or other plastics, the base material is weakened somewhat. One should take this into consideration if one decides to use any kind of paint on something like a PVC archery bow that is subject to significant stress during use.


Hope this information helps someone. Have fun and stay safe.

More on Making a PVC Pipe Archery Bow

Regular readers of this blog will recall the piece I wrote about my experimental PVC archery bow. I wanted to see if one could actually produce a longbow type archery bow easily and cheaply using PVC. Between family, school, and other demands I have not gotten out to shoot it yet. See my previous post here:
http://inkarlslab.blogspot.com/2011/06/homemade-pvc-pipe-archery-bow.html

While doing some research a couple weeks ago I stumbled upon this interesting you-tube video. It details how to make a PVC bow that is considerably more elaborate than the one I made and wrote about. It's owner claims 60 pounds draw weight - quite respectable, in my opinion.

http://themanscave.com/hunting-outdoors/pvc-bow/

There are plenty of sites online that deal with PVC as a cheap and readily available material for making archery bows. Here is a quick distillation of what I have learned:

USE EYE PROTECTION when shooting ANY archery bow!! Any bow made of any material could potentially break. This could cause eye injury, depending on where the pieces fly. I've also heard of strings breaking and swatting people in the face, too.

1) While PVC will work, it does NOT have the speed or the "snap" of wood or fiberglass. In other words, when the string is released, a PVC bow of a given design and draw weight will take slightly longer to return to the relaxed position. Thus it will not produce as much arrow velocity as other materials.

2) PVC will develop a "memory", or "take a set", if it is left strung all the time. Thus, one should always unstring the bow when not in use.

3) On ANY "traditional" style bow, you want a brace height of 6" - 7". The brace height is the measurement between the string and the handle - in this case as measured at the middle of the bow. I should adjust mine by shortening the string slightly; the brace height is about 4.5".

4) The "composite" design of "Themancave's" bow offers the advantage of better speed due to the fiberglass rod core. Doing as he said by using a 1/2" pipe slipped inside a 3/4" pipe might also help protect against breakage - though I'd use soap or lanolin instead of petroleum based oil as the assembly lubricant.

5) If you paint PVC as "Themanscave" did, beware that the solvents in the paint will eat into the PVC and weaken it somewhat. Krylon and Rust-Oleum both make a spray primer for PVC. This primer is supposed to help the paint bind to the PVC. I'm currently using that on my own PVC projects to hopefully avoid the paint flaking I've experienced in the past.

6) As I mentioned in my previous post on this topic, PVC gets quite brittle at temperatures below the mid 40's Fahrenheit. So don't try to shoot it in cold weather. PVC also degrades due to UV exposure - so don't leave your PVC bow exposed to sunlight when not in use. Painting your bow will protect it from UV exposure, but as I mentioned above the paint itself will weaken the material slightly.

While PVC does have certain disadvantages as pointed out above, it can be a viable way to obtain a bow quite cheaply and easily, and also might prove to be a useful emergency technology in a survival situation.

If any readers have made and used a PVC bow, I'd love to hear from you. In a future post I plan to cover simple "home and hardware store" materials to use for making bowstrings.

A Homemade PVC Pipe Archery Bow

For thousands of years, the bow and arrow have been used for both sport and survival hunting. Even today it is still used throughout the world. In America, it is primarily a sporting weapon, though occasionally it is still used for more serious purposes. For example, during the Vietnam conflict, American Marines were said to have used bows and arrows for relatively close situations where a quiet, discrete weapon was needed.

Ever since I was a boy, archery has fascinated me. I had never owned a bow nor did I have the opportunity to get instruction from anyone who could properly teach me. As an adult I fortunately was able to take archery at a local college. I did quite well in it and bought my first bow shortly before the end of the course. Since then, life intervened and I haven't shot a bow in years. While I still have my factory-made bow, I wanted to try something a bit different.

My Hardware Store Specials:
One goal of mine was to, as much as possible, stick with materials I could readily buy at any local hardware or home improvement store. When doing a project I try to avoid any hard-to-find or exotic stuff whenever I can.

I am currently doing two archery bow-building projects. Both of these are classified as "long bows", as opposed to a recurve or compound bow.

One is a "board bow" - so named as it is carved from a solid 6' piece of red oak 1" x 2" board. I have the rough shape cut out and am in the process of whittling it to its final shape. This is a painstaking process involving a draw-knife and/or a carpenter's plane. More on this project in a future post. I got the board for under $10 USD from the local Lowes Home Improvement Center.

In the picture above is another experiment I am doing - the PVC pipe bow. While handling some PVC pipe a while back, it occurred to me that given its springiness it should make a crude but effective bow. Some searches of Google and you-tube revealed numerous examples of folks who have made PVC bows. Many of them were of low draw weight and made by kids, but a few are of decent (40# or more) draw weight and made by adults. And so I made the one in the picture above. It consists of a 72" piece of 1.25" schedule 40 PVC pipe. The string is my own crude attempt at a "Flemish bowstring", made from 6 pieces of mason's line. I bought my mason's line from the local Home Depot for about $5 USD.

I haven't fired this bow yet, but I do have some arrows that are suitable for the approximate draw weight involved. In a future post I will give test results, draw weight measurements, ...
Meanwhile I have built a wooden stand for measuring the draw weight accurately and for "tillering" the board bow. "Tillering" is the process of shaping the limbs of the bow and adjusting their tension so that the bow is properly balanced.

A Word (or Two) of Warning:
If you decide to try this, BEWARE that PVC gets extremely brittle in cold temperatures! DO NOT try to use such a weapon at temperatures below 45 degrees F - it could shatter and injure you!!

Secondly, when messing around with unproven materials such as these, use some good, stout eye protection. If the string or the bow fails, you do not want the shrapnel going into your eye.

By the way: PVC pipe is great stuff; I've found all sorts of novel uses for it. PVC performs reasonably well up through VHF frequencies for winding loading coils for amateur radio antennas.
Granted, this has NOTHING to do with archery, but it is another valid re-purpose of a common commodity.