Cut 2-inch diameter PVC pipes into four pieces. Cut two 38-inch-long pipes for the width pieces and two 82-inch-long pipes for the height pieces. Use a PVC pipe cutter to make the cuts or have them cut at the hardware store when you purchase them.
Insert both ends of one of the width pieces into a three-way PVC Tee-pipe fitting. These are corner joints for PVC pipes with 90-degree angle bends and openings on each end to insert pipes. Dry-fit the pipes into the pipe fittings without lubricant or glue. If the pipe is difficult to insert, rap the opposite end of the pipe with a rubber mallet to force it into the pipe fitting. Adjust the pipe fittings so that the open ends point in the same direction.
Repeat Step 2 with the second width piece and two more three-way PVC Tee-pipe fittings. Dry-fit the pipe fittings together on the second width piece and adjust the fittings to face the same way.
Place the two width pieces parallel to one another on a work surface and spaced 80 inches apart. Align the width pieces so the 90-degree angle bends of the three-way pipe fittings face the opposite width pipe.
Connect the two width pieces together by inserting one of the height pieces into the three-way pipe fittings on either side to create the door frame.
Insert a 2-inch-diameter PVC pipe into each of the open pipe fittings to attach the door frame to the PVC structure. The length of the pipes depends on the length needed to create the desired wall.