How-To
Make Your Own Launcher

Making your own spud gun isn't all too hard. It may take you a few hours or searching for parts and a couple to build, but it can be a fun process. Most parts can be found at your local hardware store. Try looking around Home Depot, Menard's, ACE, etc. They should have all you need to start your project.

Take some time to browse the plumbing sections. Become familiar with the parts and how they connect. Take note that pneumatic spud guns should only use pressure-rated fittings and pipe. Never use what's called DWV (Drain, Waste, and Vent) or Cellular Core. Those materials are not made for holding pressure and can rupture. The reason for this is that tiny air bubbles are whipped into the pipe to keep material cost and weight down. You want PVC marked with PW (Potable Water). Some pipes are marked with both PW and DWV; those are fine to use for either application. Look around the metal fittings area if you are interested in propane meters or pneumatic triggering assemblies. Pressure regulators and gauges, air couplers, and hoses are generally found over by the air compressors. Sprinkler valves can be found by the gardening or irrigation sections. BBQ sparkers are near the grills. Replacement sparkers are sold individually. Flint lantern sparkers are usually found in camping supply sections.

After you know how PVC and metal fittings join, you can select the shape of your launcher and build accordingly. I find that it's best to select the parts you are using from the shelf and line them up in the configuration you plan to build in on the floor. Take the time to figure out how to make interchangeable barrels. They are a great thing to have! And yes, this is going to cost more than you expected. Go to the hardware store planning to spend a lot of money. Each fitting is going to cost you about a dollar or more, depending on its size. Other things such as igniters and specialty parts will cost significantly more.

Solvent-Welding (Gluing)
You will also need PVC primer and cement. To use PVC primer and cement, first gather your parts neatly and be sure they are all clean. You will be doing one joint at a time. Knowing what parts are called will help this process. PVC parts have two different connection types: spigot, and socket. Spigot fittings are cemented inside of socket fittings. Tees, couplers, adapters, unions, caps, etc are all socket fittings because they have a socket for pipe to slide into. Pipe is considered a spigot fitting. Other spigot fittings include bushings, plugs, and certain adapters. To weld these parts together, get the two fittings for the joint and open the primer and cement. It's a very good idea to have paper towels at the ready. I always have a neat stack withing inches of my solvent-welding station to stop any solvent drips before they start. There is an order to the process. It's not too hard to follow. Primer is always used first and should be applied in an amount that gets the entire surface wet. Prime the socket, then the spigot. While the primer is still wet, apply cement to the spigot, than the socket. Immediately after applying cement, join the fittings and rotate them in each other 45 degrees to spread the solvents evenly and create an airtight weld. Once the parts are all the way together, hold it in one hand while wiping excess solvent away with a paper towel. Be sure they pieces do not slide apart. It usually only takes 10-20 seconds for the solvents to set and you can move onto the next joint in the same manner. Let the joint sit for 24 hours before shooting or even test-pressurizing. Applying pressure before the joint is fully cured will cause leaks and can even pop fittings off. Fittings that have already been used cannot be reused.

Teflon Taping and Pressure Testing
Don't forget the teflon tape on all your threaded joints. Threads don't seal themselves. You need to put in about 5 wraps of teflon tape to make the seal. Simply wrap the tape around the pipe's male threads. You want it to be in the direction where the tape will not unwind while you screw it in. So if you are looking at the side that is being inserted, the tape winds around that clockwise. Tighten all fittings with your hand and then when you can't turn anymore, give it 2 more turns with a wrench. After it is all together (and the PVC has sat welded for 24 hours) you can pressurize it all and test for leaks with soap-water. Use Windex or something similar and spray it on the joints. If there's a leak, bubbles will form. To fix that, try tightening more with a wrench. If it feels like it's too tight, unscrew it and apply more teflon tape. If it's a solvent-welded joint then you can't fix that. Either you must deal with the leak or start over on it.

BBQ Ignition
Adding a BBQ igniter isn't too hard. Get the sparker and attach wires to the two leads. If you only have one connector on yours, there is a very thin bare wire running down the side which you should tape a wire lead against. Those two wires should each lead to a screw which passes through the chamber wall. It's suggested that these screws go through a double-layer of PVC for extra strength. The best place for that is generally the rear pipe and female adapter joint.. Just put the screws in so they come to a point with an 1/8-1/4 inch gap and secure the wire leads to them. Be sure the heads of the screws are not as close together as the tips of them are. If the screws are too far away for the spark to work correctly, bending them closer isn't against the rules.

Be creative!
Add something special to your launcher, Make a nice paint job. Add tons of barrels. Make a neat launcher shape. Do some research to see what others have done. There are tons ow ways to build one of these and the list keeps growing. Make something and please tell me all about it. The guys on the forums would love to see your work!