A waterbed is little more than a frame that holds a water bag in place and sits on a pedestal to raise it above floor level. Before you consider building a waterbed, you should purchase the water bag and necessary fittings. You will need to know the internal dimensions for the frame, particularly if the water bag comes with a safety liner shaped so that the sides stand up.
From the details supplied with the water bag, calculate the size of the base of the frame. For example, let’s say the dimensions of your water bag are 80 inches x 60 inches x 6 inches. Then you must adjust for the thickness of the frame.
If you are going to make your frame 3 inches thick, the two sides of the frame will be 80 inches plus 3 inches plus 3 inches, or 86 inches all together, and the ends will simply be 60 inches long. The depth of the frame should match the maximum depth of the water bag plus half an inch. So if the water bag will be 6 inches thick, the frame has to be 6 1/2 inches high.
Step 1 – Identify Edges of the Board
Mark the sheet board so you know where it will be joined (if necessary). Identify the outside edges.
Step 2 – Drill Screw Holes
Drill the board 1 1/2 inches from the edges and about 7 1/2 inches apart. Use the wood screws and the countersink bit to create a shoulder in each hole so you can drive the screws until the tops are level with the surface of the board.
Step 3 – Prepare the Frame
Join the four heavy timber frame edges to make a rectangular frame. The best way to do this is to use wood doweling.
Step 4 – Cut the Doweling to Size
Cut the doweling cleanly into 6-inch lengths with two lengths for each joint.
Step 5 – Make a Groove
Score the doweling so that there is a shallow groove the full length of each piece. At each end of the sides, mark a line 1 1/2 inches from the end and cross each line 2 inches and 4 inches from the base face.
Step 6 – Clamp the Side and End Pieces Together
Using the "C" clamps, hold the end of one of the sides against the end of one of the ends of the frame at 90 degrees. (You can achieve this step easily if you have a piece of board that is cut at right angles so you can line up the pieces with the edges.) You will have an "L"-shaped construction.
Step 7 – Drill the Two Pieces
Using a 1/4-inch drill bit, drill a hole from each of the marks that cross the 1 1/2-inch lines to a depth of 6 inches (through the side and into the end pieces).
Step 8 – Label Each Joint
Clearly mark the ends so you can put them together again after you drill all the holes in the same way at all the other corners.
Step 9 – Assemble the Frame
Once you drill all the corner joints, lay the frame out. Ensure that you have matched the drilled pieces together.
Step 10 – Install the Doweling
Apply a coat of wood glue to a piece of doweling and gently tap it home in one of the drilled holes so it passes through the end piece and into the side piece. Excess glue will be forced out along the groove in the doweling; clean it away.
Step 11 – Complete the Frame
Methodically install all the doweling and ensure the joints are tight.
Step 12 – Fit the Baseboard to the Frame
Lay the frame on the floor and apply a good coat of wood glue along the center line of each side and end. Lay the baseboard on the frame and locate it precisely so that the edges line up and clamp it into position.
Using the pre-drilled holes, screw the baseboard to the frame. Make sure the screws are driven so they are level with the surface of the board.
Step 13 – Clean the Base
Turn the base over and wipe away any excess glue. Once the glue dries, you have a base in which to install your water bag, heater and controls.