How to Make a Spud Gun Silencer

Silencers can reduce the loud explosions emitted by spud guns.

The principles behind the spud gun silencer are the same as those used in silencers for real guns. The noise from a shot comes from the sudden expulsion of the high-pressure gases built up behind the projectile (in this case a spud). This is why you hear a "pop" when a wine bottle is uncorked. The silencer adds spacial volume that allows the pressure to bleed off as it travels through silencer. This drastically reduces the amount of pressure that exits the weapon and reduces the sound.

Things You'll Need

• Schedule 40 PVC threaded female adapter (same diameter as the gun barrel)
• One 14-inch length of schedule 40 PVC pipe (same diameter as the barrel)
• One 8-inch length of schedule 40 PVC pipe (twice the diameter of the barrel)
• Two schedule 40 PVC couplings (sized to fit the 8-inch pipe to the 14-inch pipe)
• Wall insulation material
• Work gloves
• File or circular sander
• Drill press
• 3/16-inch drill bit

Instructions

1. Use the file or circular sander to remove the ridges inside the couplers, allowing them to slide freely onto the 14-inch piece of pipe.

2. Attach the female adapter to one end of the 14-inch length of pipe.

3. Slide one of the couplers onto the 14-inch length of pipe until it touches the female adapter. The larger side of the coupler should be facing away from the adapter.

4. Slide the 8-inch section of pipe into the coupler and attach the second coupler to the other side.

5. Adjust the assembly until there are roughly two inches of the 14-inch pipe showing on the side without the female adapter. Mark that point on the pipe.

6. Remove the assembly and draw dots along the 14-inch pipe between the two points that mark the coupler positions. Leave approximately 3/4 inch between each dot. Rotate the tube as the dots are drawn so that there are dots present around the entire outside of the tube between the coupler marking points.

7. Repeat this process with the 8-inch pipe section, but leave 1 to 1 1/2 inches between the dots to reduce their overall number.

8. Drill 3/16-inch holes through the dots on both the 14-inch and 8-inch pipe sections.

9. Slide the bottom coupling onto the 14-inch pipe up to the position marked in step 5.

10. Slide the 8-inch piece of pipe into the coupling.

11. Fill the void between the two pipes pieces with wall insulation material. It is important to avoid packing the insulation too tight, but there should be enough so that some will enter the top coupling once it is attached.

12. Attach the top coupling and screw the completed silencer onto the spud gun using the female adapter.

Tips & Warnings

• The lengths can be adjusted according to the design and overall length of the base spud gun. Test the silencer and add more holes or change the packing material if the sound is still too loud.

• Use gloves when handling the insulation material, as it is very irritating to the skin.

References

• How Stuff Works: How does a gun silencer work?
• Advanced Spuds: Silencer