Spud Launchers

What you need and how to build a Spud launcher!

Step 1- Materials

1. Cut a 40" length of the 2" piping
2. Clean and trim the end that will be bonded to the reduction fitting
3. Taper the inside of the other end with a file, knife or Dremel tool (see Figure 1)
4. Cut an 18" length of the 3" piping
5. Clean and trim both ends
6. Clean the bonding areas of the cleanout plug and the bell reducer
Note: The cleaning step is important to ensure that the bonds between the sections of PVC have adequate strength. Use only PVC cleaner, as it the only thing that will do the job properly.

Step 2- Construction

Part 1- Barrel/Combustion Chamber Assembly
Attach the 2" section and the appropriate end of the bell reducer fitting with a liberal amount of PVC glue.  Attach the 3" section and the endcap, again using a liberal amount of PVC glue
Note: PVC glue dries quite rapidly and does not allow for much working time. Try to work quickly to achieve the best joint possible. Also, though PVC glue does not take that long to dry completely, make sure you allow enough time for the joints to cure. Failure to do so will compromise the structural integrity of the device. Attach the end of the 3" combustion chamber to the 3" end of the reduction fitting.
Note: This is the most critical joint and care must be taken to ensure it has the proper strength to withstand the pressure generated inside the combustion chamber. Use plenty of PVC glue and make sure the pipe fits all the way into the fitting.

Part 2- Ignition System
Drill out the center of the endcap to accomodate the igniter
Note: Use a slightly dull drill bit if possible. Sharp new bits can "bite" into the plastic too much and make it difficult to drill straight through the endcap. Be prepared to finish the hole with a knife or X-Acto blade. Trim the PVC coupling so that it will slide over the igniter and stop just below the grounding tab on the body of the igniter.
Bend the paper clip in an "L" shape as shown in Figure 3 using a vise, pliers or whatever tools present themselves
Note: Make sure the paper clip is not too far from the end of the igniter, otherwise it will not create a spark. Solder the paper clip to the grounding tab on the body of the igniter. Push the igniter through the hole in the endcap and secure with epoxy.
Note: The epoxy must be thoroughly mixed and applied to clean surfaces. For best results, keep the parts in place for 5 minutes. Wait for the epoxy to dry (usually 5-10 minutes) before proceeding. Make sure to use epoxy, as PVC glue is intended only for PVC to PVC bonds. Apply epoxy to the butt of the endcap and the lower portion of the igniter.  Slide PVC coupling over igniter and keep in position for 5 minutes.

Step 3-Construction Notes:
Allow both components to cure 12-14 hours before test firing Teflon tape on the threads of the ignition system makes it easier to screw into the combustion chamber.

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My Spud Launcher!

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