Sunday, August 24, 2014
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.