Halfpipes are one of the most versatile ramps in all trick sports, including skateboarding, BMX biking, and rollerblading. Riders can do jumps, spins, flips, stalls and even grinds using the ramp and coping of the half-pipe. Because of the high number of tricks that can be performed on a half-pipe, it can be fun, and useful for practicing. Building the pipe yourself allows for customisation, a far cheaper price than pre-made pipes, and can be a rewarding experience.
Lay down a plywood board. Tie a string around a pencil, and cut it six feet long. Start the pencil at the top left hand corner of the plywood. Keeping the string taught, draw to the right an arc until the pencil comes off the edge of the board.
Measure back four feet from the end of the arc. From that point, draw a line straight down to 3 1/2 inches below the lowest point of the arc, then draw a line perpendicular to that to the other end of the arc. Saw the sides using a skill saw, following the lines you drew. Use this as a template to make three more arc sides just like it.
Cut out two 3 1/2-inch tall and 6 feet long strips from plywood. Nail them onto opposite ends of a 2x4. Make sure the 2x4 is at the right end of both of them, and the 4-inch tall side of the 2x4 is vertical. Nail another 2x4 on the other side. This piece is the centre side that will be attached to the arc sides.
Place a pair of arcs on the edges of a 2x4. Do the same thing to them that you did to the strips. Then repeat this with the other pair of arcs.
Nail the 2x4s of the arcs to the 2x4s of the middle section; use multiple nails to hold them together.
Evenly space out six 2x4s between the two end 2x4s of the middle section. Nail them into the sides of the plywood.
Nail six 2x4s between the arc sections of the pipe. Make sure they are facing parallel to the slope of the arc it is currently at and are evenly spaced.
Cut a 2-inch square notch into the 2x4 at the top of the arcs.
Nail one 2x4 into the top back corner of the end sections of the half-pipe. Nail another one two feet in front of that.
Cut an 8 feet wide by 3 feet, 10-inch long plywood board. Nail it flush with the top of the arc onto the three 2x4s.
Take four 2x4s and cut them so that they are 4 feet by 5 inches tall. Then nail them between the top 2x4 and the bottom 2x4, two on each side of the half-pipe.
Drill four large holes that a screw head can fit through into both metal rods, and on the other side drill a skinnier hole that a screw base can fit through.
Place the metal rods in the square notches cut in the 2x4s, and drill a screw through the larger hole into the bottom of the 2x4.
Take an 8 feet wide by 6 feet long plywood board and nail it down onto the middle section of the half pipe. Nail a second board and a masonite board of the same dimensions on the first.
Use a measuring tape to determine the length of the arc of your half-pipe. Cut four plywood boards that length and 8 feet wide.
Nail the boards onto the 2x4s on the arcs, slowly bending the board into the arc.
Nail another pair of boards onto the first to strengthen the half-pipe.
Nail masonite boards down to smooth the surface, and then you are done.