# PVC Perfections bow test



## Hank D Thoreau (Dec 9, 2008)

First I will show the main panels for the PVC bows. You will notice that both bows store energy pretty well. This will be more evident in the comparison charts.


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## Hank D Thoreau (Dec 9, 2008)

The next two charts compare the 2 PVC bows with the Samick SLB longbow. 

1) DFC: The Crimson LB has a large position deviation from linear at the start of the draw, but drops, considerably, late in the draw.
2) Potential Energy: The Samick SLB and Yellow Jacket are very similar at full draw, with the Crimson LB lagging behind at all draw lengths.
3) Smoothness: The smoothness of the two longbows is very similar, with the Samick stacking more at the end. The Yellow Jacket is very smooth, which is noticeable when drawing, and in the first derivative curve. This is the affect of the syiahs.
4) Energy per weight on the fingers: The Yellow Jacket is king here, store much more energy per weight than either of the longbows, which are very similar.

The next test is how they perform with an arrow.


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## Hank D Thoreau (Dec 9, 2008)

Next I will show chrono readings. This is where the PVC bows fall behind. I use 31 1/2 inches as my draw length since these bows are narrower than a recurve.

My test arrows were six 503 +/- 6 gr wood arrows with 5 inch feathers.

Crimson Longbow: 108 +/- 1 fps - efficiency = 37%
Yellow Jacket: 112 +/- 2 fps - efficiency = 38%
Samick SLB: 143 +/- 1 fps

Certainly, one contributor to the very low efficiency is the fact that the limbs do not get lighter toward the tips. This means that you are accelerating a lot of mass.

Nick, the Backyard Bowyer actually tested a PVC bow at 171 fps with 435 gr arrows and a highly reflexed bow design. That gives me a target to shoot for when I start making my own bows.

http://www.youtube.com/watch?v=zDO__SNuEOI

I decided to see how much speed I could generate with some lighter arrows. 

With the Yellow Jacket I got the following:

344 gr ACE: 125 +/- 1 fps
435 gr ACC: 119, 118, 107, 102, 118, 111 and 97. The ACC were very inconsistent which I believe is from the 3 inch plastic vanes being shot off the hand. The ACE has FFP250 which, I believe, resulted in less interference.

In conclusion, they are not fast, but they are fun. There also may be ways to make them faster. I hope to use PVC as a way of rapid prototyping designs to see how different features affect performance.
__________________


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## Thin Man (Feb 18, 2012)

Interesting stuff, and thanks for the great information and comparisons. Good luck with your own designs.


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## wseward (Mar 7, 2013)

Congrats on the new bows. PVC may be a good inexpensive material for the testing of bow design features.

When working at the UCB Aquatics Program (Boating Saftey), I used schedule 80 PVC pipe to fix lobster/crab trap floats to the tops of sailboat masts. When they capsised, which they frequently did, it was less likely for the boats to turn turtle and stick their masts in the mud. PVC is a tough material for the cost.


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## GPW (May 12, 2012)

Hank, Thanks !!! That’s a great scientific comparison ... Thinking we can optimize the efficiency with more bow design experiments ... Our 48” PVC bows shoot much faster than the 60” ones ...even at a looong draw length ... which we would Not do with a regular bow , and NEVER with a wooden bow ...


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## scout4 (May 18, 2010)

I think pvc bows make a good low cost option to building wooden bows, but I wonder just how durable they are and how well the pvc longbow would hold up in cold weather, if for very long at all? If not out-right fail to splinter or complete breakage, the performance would certainly be hindered.
scout4


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## Hank D Thoreau (Dec 9, 2008)

GPW,

I am planning on doing some experiments with the goal of determining which design factors most affect: energy storage, smoothness, speed, and efficiency. PVC seems to store energy very well. Transferring the energy into the arrow is the issue. I want to see if I can use the analytics from my bow testing to optimize the design and to be able to tune performance variables to achieve a desired outcome. My bow test database currently contains performance data for over 30 bows (and growing as I test more) of various types, which gives me a lot of options for comparisons. I can compare up to four bows at a time by selection from pull down menus. It is too bad my kids are through with science fairs. It would be a great experiment.


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## Hank D Thoreau (Dec 9, 2008)

I have a typo in the website. It is www.pvcperfection.com. Take a look. They are fun bows and very affordable.


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## scout4 (May 18, 2010)

Yes Hank D. I have seen this Fellow's site. You are right about them being low cost. Seems from what I've read on these pvc bows that once you have a basic form and heat gun you can make up just about any type bow. I have had contact with a lady from California that makes and sells these pvc bows, she has stated that pvc longbows with perhaps the last 8 inches tapered and flattened toward the belly side will give the best performance. Also easy to make the single string groove into the tip. It may well be that the longer a bow is with this type limb ends, then the longer could be that taper. So instead of an 8" taper you can make it more like 10". And so, if you have made say a 66" longbow with a 4-6" handle section, you should be able to taper and flatten about the last 9-10" of limb and this should make for a pretty quick shooter from a 1" pipe. Also the diameter of the pipe effects draw weight. ie, 1 inch at 66 inch may well render a 50# longbow. Let me know what you think. Thanks! scout4


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## Hank D Thoreau (Dec 9, 2008)

scout4,

I got all the tools and made the flattening jig. All I have left to complete my first bow is to cut the nock. I ran out of time today. I had to exchange my heat gun for one with more power. It takes a lot more time and heat than I thought to get the PVC soft. It looks much easier in the videos. I built a basic longbow with recurved handle. My limb tips are a couple inches forward of my handle when unstrung. I will have to see how much set it takes. This should give me some extra speed.

Nick shows how he tapered the tips by cutting a wedge out of the end, heating, and them pressing the two end together. He then glues. This would remove weight from about 6 inches of the limb tip which should help the speed. I may try this if I manage to get to next weekend before I get a chance to finish the tips.


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## scout4 (May 18, 2010)

Hank D here is a pic of a the kind of limb end I'm saying. This is one of the bows she makes. I don't think she'll mind me showing her handywork here, as it is promoting her sport. She is a great lady and really knows this stuff well! I have one of her recurve's. scout4


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## Hank D Thoreau (Dec 9, 2008)

Scout4,

That is flattening the PVC at the end of the limb, but it does not remove material, so it does not lower the weight of the tips. That is similar to what was done with the syiahs on the Yellow Jacket, except the syiahs are reflexed, for more power. The syiahs are also made of 3/4 inch tubing, which reduces weight at the tips, as long as the joint with the limb does not cancel out that gain. I am going to lighten the limb tips on my first attempt (I already have the limbs marked). My only concern is that it might negative affect the tiller by making the tips too weak.


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## wseward (Mar 7, 2013)

Hank D Thoreau, Careful guy. A lot of the wood bows I have made I wear a full face bike helmet, good eye protection and additional clothing...just in case when I first start shooting them.

Might want to skip the paint as well just to be able to monitor the structure of your materials over time. Is PVC UV sensitive over time? Most of it gets buried in the ground or a wall.


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## JDBrown (Jul 18, 2013)

wseward said:


> Hank D Thoreau, Careful guy. A lot of the wood bows I have made I wear a full face bike helmet, good eye protection and additional clothing...just in case when I first start shooting them.
> 
> Might want to skip the paint as well just to be able to monitor the structure of your materials over time. Is PVC UV sensitive over time? Most of it gets buried in the ground or a wall.


Long exposure to UV does cause PVC to deteriorate -- that's the main reason you should only use new PVC for making bows (the date of manufacture is printed right on the pipe). If you buy pipe that is several months old, it may have spent most of that time sitting out in the sun, deteriorating somewhere.

PVC's UV sensitivity is one of the reasons many electricians, plumbers and landscapers will transition to metal pipe for risers that will come up out of the ground (the other reason is metal is just plain stronger). However, if PVC needs to be installed in a location where it will be exposed to sunlight, you can protect it by painting it with several coats of metallic paint (the kind with actual metal in it). That will block the UV and protect the underlying PVC. You can then paint whatever color you want over the top of that.

But really, that's advice for pipe that will be installed, say, on the exterior wall of a building -- where it will be exposed to sunlight all day, every day. As long as you don't store your PVC bow in direct sun, UV shouldn't be a problem for you.


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## Hank D Thoreau (Dec 9, 2008)

wseward said:


> Hank D Thoreau, Careful guy. A lot of the wood bows I have made I wear a full face bike helmet, good eye protection and additional clothing...just in case when I first start shooting them.
> 
> Might want to skip the paint as well just to be able to monitor the structure of your materials over time. Is PVC UV sensitive over time? Most of it gets buried in the ground or a wall.


I guess it would not help to mention that I have a 32 inch draw length. When I got my board bow, I pulled it first on my draw board. Then I pulled it with safety glasses. I did not take it to full draw until the second day. I have had two bows explode on me. An English longbow exploded into three sharp pieces. Pieces hit me above each eye, on the eye brows, leaving bumps. The other piece flew over my head. The second bow exploded near the end of the 70 meter round of a FITA. I had just shot a personal best at 90 meters. I had 11 arrows to go to get a first day personal best when the limb went and hit my an inch below my left eye. That was the end of that tournament.


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## Todd the archer (Feb 7, 2003)

I have had two PVC bows break on me and both at full draw. No injuries! They were shorter bows with wood siyahs and using 1" pipe. They drew around 55 pounds @ 27" and both both were shot hundreds of times before they failed. Pipe was not old or store in sunlight and was not scorched when heated up. Most likely they pushed a little too far in design stresses. However they did shot nice with only a small amount of hand shock and had good speed (for what they are) around 155 to 160 with a 500 grain arrow.

Todd


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## scout4 (May 18, 2010)

Hank, make the bow! Just as you want. From what I've seen a longbow made of this stuff is not going to explode on ya, and I think you'll have good longbow for a long time. One thing is certain. [IF] and that's a big if, something goes wrong with it you will not be out hundreds of dollars. So then you get another 3/4" pipe and make another longbow.
And also, after ya got the bow done and put a bunch of shots through it, give it a dandy paint job before you post up photo's will you please?....man, I can't stand all them letters and numbers all up the side of them once they made into a good looking bow! :wink:
Thanks Hank! Good shooting! scout4


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## GPW (May 12, 2012)

Besides good bow design , Speed is most always a function of draw weight , the heavier the draw weight , the faster the arrow leaves (generally speaking) ... the really Nice thing about PVC is if you want a heavier weight bow , just go up a pipe size... Since PVC doesn’t seem to “stack" when drawn , a few more pounds shouldn’t be a big deal , and draw comfortably ... 
It’s been said the Gray PVC schedule 80 is more resistant to UV and COLD ... 

Hank, we’d be glad to send you one of my Asymmetrical PVC bows which shoot fine and have almost no hand shock ... for testing ... Although “strange" compared to other bows , it shoots Nice and Fast enough for taking Meat at my usual 15 yd. hunting limit ... Just another design consideration... :set1_thinking:


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## Hank D Thoreau (Dec 9, 2008)

I finished my first bow. It is a simple 62 inch longbow with tapered tips. I had made if quite reflexed for extra energy, but I could not string it. I end up stringing it deflexed. The bow is quite a bit heavier, at 45 pounds at 28 inches, than the two PVC Perfections bows, even though mine was the same length and used the same diameter pipe. I must not have tapered the thickness of mine enough. I found that you have to get use to working with the PVC. Tapering the tips was a lot harder than I thought. The bow is not pretty but is was not bad for a first effort. Before you ask, it is too dark to take a picture. Maybe I will add one tomorrow.

I did manage to soundly break the speed record of the PVC Perfections bow, though it was completely driven by draw weight. My bow clocked an average of 128 fps, with a 38% efficiency. The energy per weight on the fingers (ability of the bow to store energy) lagged behind the PVC Perfections bow until 32 inches of draw. So, in conclusion, it was much heavier, it did not store energy as well, but matched the efficiency of the Yellow Jacket, which was the most efficient of the PVC Perfections bows. All this combined to give a faster bow. Here are the comparison charts.


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## GPW (May 12, 2012)

That looks like a Big PLUS for PVC, and a smooth draw too ... 

Just a thought ... by adjusting arrow weight, we could get some fairly high speeds for those that have the “Need for Speed “ ... Just sayin’ ...


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## Hank D Thoreau (Dec 9, 2008)

GPW,

I am going to test some lighter arrows later today. I will run my 344 gr ACE and 435 gr ACG through it. Those are my target arrows and are not set up for shooting off the hand, but they will give an indication of extra speed. I did the same with the PVC Perfections bows, except I used some ACC with larger vanes instead of the ACG. I reread your post about sending a PVC bow to test. I will PM you about that later. I am heading off the a 3D this morning. 

My extra draw weight came from the fact that I did not flatted the PVC enough. Stiffness is dependent of the distance of separation between the power generating surfaces. My surfaces were too far apart. That said, my tiller looked good.

Now the fun begins as I start diddling with the design to see what effect it has on the performance.


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## wseward (Mar 7, 2013)

Congrats on the new bow! Interesting data.


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## rattus58 (Jul 9, 2007)

Hank D Thoreau said:


> GPW,
> 
> I am going to test some lighter arrows later today. I will run my 344 gr ACE and 435 gr ACG through it. Those are my target arrows and are not set up for shooting off the hand, but they will give an indication of extra speed. I did the same with the PVC Perfections bows, except I used some ACC with larger vanes instead of the ACG. I reread your post about sending a PVC bow to test. I will PM you about that later. I am heading off the a 3D this morning.
> 
> ...


I was looking at some video's regarding pvc bows and this kid Backyardboyer has a number of pvc bows some of which he has chronographed. One 55# bow he tested of someone else was pushing his I think 435 grain arrows at 135 fps or so. I saw another of his bows that were around 150 fps. I can imagine what a 700 grain arrow would do.... :grin: I think these bows are a great innovation if you want to have an inexpensive bow you can make yourself... :grin: You've done an interesting job of comparing data.

Aloha...


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## Hank D Thoreau (Dec 9, 2008)

I put a link to Nick, the Backyard Bowyer's fastest in post #4. I am still not sure how he got 170 fps with a 45 pound PVC bow with 430 gr arrows. I would like to test that bow myself just to make sure his chrono is okay. I am working on it. Bow one is now discarded and plans are started for bow 2.


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## rattus58 (Jul 9, 2007)

Hank D Thoreau said:


> I put a link to Nick, the Backyard Bowyer's fastest in post #4. I am still not sure how he got 170 fps with a 45 pound PVC bow with 430 gr arrows. I would like to test that bow myself just to make sure his chrono is okay. I am working on it. Bow one is now discarded and plans are started for bow 2.


I missed that one... most of what I've seen have been in the 135 to 150 range.... I'll go back and look at post 4... thank you!

Well there is something about that bow probably that is giving it its speed. He was commenting on the penetration he got with it as well. Nice looking bow.

Aloha... :beer:


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## Hank D Thoreau (Dec 9, 2008)

rattus58,

I think you have to get better than 38% efficiency to get the speeds in that test. So far, my bow, and the bows from PVC Perfections were right on at 37 to 38%. 

As far as penetration, he was shooting at an old suitcase that probably had some sort of filling in it. He mentioned that the penetration was greater than he had seen before. That is a relative statement. I would not conclude anything from that test without knowing what he was shooting through and what the conditions of the test were. 

My next goal is to see if I can push PVC higher than 37 to 38%. Without a much higher efficiency, speeds will be limited.


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## rattus58 (Jul 9, 2007)

Hank D Thoreau said:


> Hopefully this will not be a duplicate. I posted this information a few hours ago and it did not seem to take.
> 
> I put a link on post #4 showing Nick, the Backyard Bowyer, clocking a 45 pound bow with 430 arrows at 170 fps. That seems like a lot for PVC, considering the very low efficiency levels I am getting. The efficiency of my bow, 38%, was right on with the bows that I got from PVC Perfections. I would like to get ahold of that bow to see what I get. Here is that link again: http://www.youtube.com/watch?v=zDO__SNuEOI .


Why don't you write or email him and ask him if you can borrow that bow?

Much Aloha,


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## Hank D Thoreau (Dec 9, 2008)

Rattus, you caught that post before I had a chance to delete it. Actually, I sent him a message a couple of weeks ago about heat guns and I did not find an answer. I say find because I may not have looked in the right place. Maybe if I send him a link to this he will respond.


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## rattus58 (Jul 9, 2007)

Hank D Thoreau said:


> Rattus, you caught that post before I had a chance to delete it. Actually, I sent him a message a couple of weeks ago about heat guns and I did not find an answer. I say find because I may not have looked in the right place. Maybe if I send him a link to this he will respond.


I bought a ryobi paint peeler for about 60 and my wife told me that when wife was buying paint for my poochie palace.. she saw it for 30 at home depot... :grin: I actually used it to make pvc wire strand towers to keep my dogs from scaling the fence.... worked flawless... learned a lot from that kid...

As for pvc you can with a cardboard channel wrapped in tinfoil turn pvc into a noodle in about 3 or 4 minutes... cool beans...


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## scout4 (May 18, 2010)

Hank D. Have you made any more of these pvc longbows? 
Would really like to see what you came up with as I am about to venture into making one of this type longbow myself.
May I ask what arrows you have found are working the best for you considering the efficiency of the bow you made?
The charts you have are pretty cool! I like all the data you've found about these bows so far.
I'm going to test the one bow I bought for cold weather, just interested in finding what will come of it in 30 degree temps.
Thanks Hank!
scout4


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## Hank D Thoreau (Dec 9, 2008)

More bows and test to come. Nick, the Backyard Bowyer, joined AT and sent me a long PM with some very useful information about PVC bow design/performance relationships. He is very helpful and many credit his videos for teaching them how to build these surprising bows. I have not yet started bow number two. I will probably start my next this weekend.


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## Beendare (Jan 31, 2006)

My guys work with PVC daily. Have you thought of a hybrid? Utilizing the tubular shape maybe and using 1/2 a pipe as backing or belly with some other material. what about fiberglass backing the PVC to counteract the brittleness? If you are just experimenting to find the materials limitations then it seems to me you are almost there. Its heavy, brittle and seriously affected by temperature, I just don't see it being suitable bow making material.


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## scout4 (May 18, 2010)

Hank D Thoreau said:


> More bows and test to come. Nick, the Backyard Bowyer, joined AT and sent me a long PM with some very useful information about PVC bow design/performance relationships. He is very helpful and many credit his videos for teaching them how to build these surprising bows. I have not yet started bow number two. I will probably start my next this weekend.


Okay Hank D. Thanks! I hope Nick the backyard bowyer will do some posting. There is a group of folks here that are interested, so he will surely have fans.
scout4


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## scout4 (May 18, 2010)

I had my pvc bow outside this afternoon. I did leave the bow outside for about 3 hours so it would be good and cold when I tested it. 
I did flex the bow to half draw several times before making a full draw. Then just went ahead an let loose several arrow shots. Much to my enthusiastic pleasure
nothing at all happened to my bow and it actually shot well for me! My son did take a video of this which has been downloaded to my email, but I do not know how to get it from there to here. I actually did attempt to load it to post here but I think the file is to large. Anyway, the bow shot well and nothing blew apart, so that was pretty sweet!!! Thanks!
scout4


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## pfbows (Jun 12, 2013)

I have been making the PVC stuff for a little over a year, broke 2 out of 35. I think the grey electrical conduit PVC is much less likely to break, none of them have snapped. I am sticking with the Asian type horsebow style (58-63"). These seem to work the best. For a safety pre-caution I would highly suggest that you slide some bicycle inner tube over the stress areas to "capture "& prevent the flying shrapnel..(been there, felt that 2X ) No...know...fun. Currently I'm experimenting with bonding some innertube rubber to the back of the sch 40 to bring the draw weight to the 45-50 lbs. with better snap. (kinda like a sling shot,cable bow, or speargun cloned mutation *)I would be interested in trading bows with other like minded builders. Photos would be needed before a trade.


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