- 1). Determine the inside size and shape of the cooler that the manifold will be placed into. Use a tape measure to get the exact inside dimensions.
- 2). Draw the inside outline of the cooler on a piece of graph paper, using each square to represent one inch. Be sure to mark where the cooler's drain hole is on the paper.
- 3). Draw the overall shape of the manifold on the graph paper, inside the shape of the cooler. If you are designing the manifold for a square or rectangular cooler, draw the overall shape as a square or rectangle with its outermost edge an inch or two away from the cooler wall in all places. If the cooler is round, the manifold can either also be round, or can be square, with its corners nearly touching the cooler walls. Draw the pipes of the manifold half a square wide.
- 4). Connect the overall shape of the manifold to the drain hole with another pipe. Make this connection as direct as possible. The side of the manifold you connect this pipe to will be your "drain side."
- 5). Draw several straight pipes connecting the drain side of the manifold with the opposite side. Make these pipes parallel to the other two sides of the manifold and evenly spaced. The maximum space between any of these new pipes should be two times the distance between any of the outermost pipes and the cooler wall.
- 6). Draw lines across the pipes an inch away (in every direction) from a corner or a junction between pipes. These roughly mark the edges of the fittings you will need to build the manifold.
- 7). Draw a series of hash marks across all of the pipes, except the drain pipe. Do not draw hash marks over the fittings. These represent the cuts you will need to make in the pipes to allow water to flow into the manifold. Draw three to four hash marks per inch of pipe, each one extending most of the way across the pipe.