PVC pipe is fairly smooth, both inside and out. It works great for blowguns that are 4 ft. or shorter. It is also a quieter, warmer material that is easy on the mouth. It accepts camo paint really well, making it my choice for shooting sparrows in the brush. If you choose to use PVC, make sure that the piece is fairly rigid, and more importantly, as straight as possible. PVC is also the best choice for the beginner.
Copper pipe also is smooth. It works great for longer airguns (5+ feet), where greater velocity is required in hunting larger game like rabbits. In choosing copper pipe, make sure that you use type M or type L rigid pipe, don't try messing with the flexible tubing stuff. Type K rigid pipe is way too heavy to use, and chances are, you won't find it anyway. Select a piece that is as straight as possible.
For those who are serious about blowgunning, you may wish to order aluminum pipe. It is fairly strong, but its greatest advantange is being lightweight. It tends to be more expensive than the other choices I have presented, as well as harder to obtain. Check out OnlineMetals.com, they should have what you need.
What diameter should you use? I personally use 1/2" pipe, though some use 3/4". I guess I am not filled with too much hot air! Try both out for fun, and stick to which ever works better for you.
From Pipe to Blowgun
For those building a longer gun, again let me stress the importance of using copper pipe over PVC. PVC will bend under its own weight causing inaccuracy.
Once you have cut the pipe to length, you will need to remove the burr, or the roughness caused by cutting. Take a round file or Dremel and file away the rough edges, both inside and out. That will ensure smooth dart entry and smooth lips as well. At this time, also make sure that the pipe is still straight. If it is not, try to straighten it, or start over with another pipe.
Congratulations, you now have a working blowgun! If you plan to hunt with it, you'll want to paint it. I recommend using the Krylon Camoflage Paint System, available at your local department stores. It is a flat, long-lasting paint. Rough up the outside of the blowgun with 320 grit sandpaper, then wipe with a tack cloth. You might want to use primer prior to painting copper blowguns. The blowgun can now be painted in any manner you choose.
A good alternative to painting is to wrap the gun with camo tape. Just make sure that the outside of the tube is clean, dry, and grease-free to ensure proper adhesion. This especially works well on the copper blowguns, as the paint has a nasty habit of chipping.
To prepare the gun for shooting, take a piece of fishing line long enough to run completely through the blowgun. Tie one end to a sinker, the other end to a piece of old T-shirt. Lightly oil the T-shirt, and run through the gun several times to clean and lubricate it. Don't use too much oil, it'll screw up your darts if you do! Hang on to this cleaning rag, you'll need it later on to clean spit and dirt out of your gun.
You now need darts to try out your gun. Go on to our dart construction section!