Copper piping will give your deck railing an interesting, artistic look. The railing can be strong if you attach the uprights correctly to the deck framing. Assembly will be a bit like a Lego project, and it will be a good idea to have extra connectors on hand, including tees, crosses and brackets. Use type-L rigid pipe with a 1-inch diameter to make your railing safe, and avoid the discoloration and mess of soldered joints by using epoxy glue.
Measure the distance from the edge of the deck to the inside edge of the rim joists. Mark post locations at the corners and at 8-foot intervals in between at this distance from the edge. Drill a 1-inch hole through the decking at each mark.
Insert a length of pipe into each hole that extends to the bottom edge of the rim joist and 4 inches above the surface of the deck. Plumb the pipe with a level and drill a pilot hole through it about 1 inch from the bottom and screw it into the rim joist. Affix the pipe to the rim joist by attaching three equally-spaced pipe brackets, making sure the last one is as close to the underside of the deck as possible.
Glue 1-inch crosses to the tops of all the posts except the ones on the ends. Glue 1-inch tees into these with the open end facing the adjacent post. Cut lengths of pipe to fit between the posts and insert them in the crosses after applying glue. At the corners, insert a 2-inch length of pipe and glue on a 90-degree elbow so that it faces the next post. This is the bottom horizontal rail.
Cut 16-inch pipe lengths and glue them into the tops of each cross or tee. Glue crosses and tees on to the tops of these and assemble the middle horizontal rail following the procedure in Step 3.
Cut 16-inch lengths of pipe and glue them upright in the crosses. Glue tees to the tops of these and construct the top rail in the same way as the other two.