By the time you reach high school as a baseball player, the competition becomes much more intense, especially if you're a pitcher. Batters become bigger and stronger, meaning the pitches must be thrown harder and with more accuracy. The best way to become more proficient at this is to practice pitching in a simulated environment as often as possible. Building a pitcher's mound that can be transported between backyards and to different public parks and fields ensures high school pitchers always will have a realistic environment in which to practice.
Mark the treated 2-feet-by-10-feet pieces of plywood to be cut at an angle which rises 1 inch for every foot in length. The height of the standard pitching mound is 6 inches, so this means each 2x10 piece will be 6 feet in length, creating a ramp which rises this amount on both sides. Five of these 2x10-feet pieces will be used, each spaced about a foot apart. Use the 2x8-feet piece of treated plywood to make the back brace for the portable pitcher's mound, attaching it at a 90-degree angle to the cut 2x10-feet pieces. The skeleton of a 6-foot ramp will be created that gently rises 6 inches. Cut off the excess amount of the 2x8-feet plywood piece which isn't necessary for the back brace and discard it. The exact dimensions in feet of the finished frame should be 2x10x8.
Cut one 2-feet-by-4-feet piece to run across the front of the 2x10 pieces which now run along each side of the ramp. Then cut the other 2x4 pieces to connect to the front 2x4 and the 2x10 back brace. These will offer support to the entire portable pitching mound structure and should be firmly connected to each end with nails or screws. The frame for the portable pitching mound will now be constructed and should be solidly connected together, without any wobbling or cracking of the wood.
Cut a 2-feet-by-10-feet-by-12-feet piece of plywood to perfectly cover the front of the ramp. This large rectangular face of the wood should be firmly nailed or screwed into the frame of the portable pitching mound. It should also be able to support the weight of a high school pitcher winding up and throwing a baseball as hard as he can. If there is any doubt this can be done on the plywood cover, a thicker piece of plywood should be attached to the front of the ramp. Once it is attached, cut off any excess plywood from the frame of the ramp.
Roll artificial grass over the 2x10x12-feet cover of the ramp and attach it with heavy duty spray-on glue. This will simulate grass on the portable pitching mound and give pitchers some traction while they practice pitching so that they do not slip off and hurt themselves. Allow the glue to dry the artificial grass to the plywood ramp for at least two to three hours.
Cut a piece of scrap wood to be 4-inches-by-18-inches and about a half inch in height. Paint it bright white and attach it with screws to the top of the portable pitching mound. This will act as your faux piece of rubber, which pitchers must use to pitch from.
Make sure the portable pitching mound is placed on a level surface and is exactly 60 feet to where you are pitching. This will more accurately simulate pitching in a real baseball game. Consider adding brackets to the outside of the portable pitching mound so that it can be secured in the ground with metal stakes. This will help to keep the portable pitching mound from moving while it is being used.
Even if the wood has been treated, it is best not to leave the portable pitching mound out in the rain as the wood can still warp slightly and break with the constant pressure from practice pitches.