To build this you will need two lengths of PVC pipe, one slightly larger in diameter than the barrel of the gun, the other about 1″ beyond that. You will also need PVC reducers that fit the pipes, cotton balls, and various cutting and finishing tools. Cut the stopper tab from the smaller pipe and put into a reducer, hammering the reducer into place. Cut the pipe about 1″ away from the reducer, being careful to make the cut as even (perpendicular to the length of the pipe) as possible. Now drill six straight lines of ten holes along the pipe with the smallest drill bit possible. Sand down the inside of the pipe by wrapping sandpaper around a cylindrical stick and move the stick in and out of the pipe. Cut the larger pipe so that it is slightly shorter than the smaller pipe. Fit the two pipes together and fill the area between the two with about 20 cotton balls. After that, fit the second reducer to the other end. At this point the silencer is functional, but guide author [MrAngryPants] suggests painting it black.

As the paintball and CO2 are expelled from the gun, the cotton baffles dampen the resulting sound wave.