Typically, PVC pipe is unattractive as part of home decor. The versatile and functional material is generally best kept hidden in basements and behind walls. However, in the case of a finished basement or challenging home improvement project, sometimes you just can't hide the PVC. Giving your PVC a faux cast iron finish can add a touch of class and character to exposed piping.
Prepare a Workspace
If you are working with PVC pipe that is unattached, and can work on it anywhere, prepare a workspace that is far from anything valuable that you don't want to get dirty. Some of the materials used in this project can be messy and permanent, so a backyard, garage or art studio would be ideal.
If the pipe is already fixed within your home, protect the surrounding area with newspaper, tarps and drop cloths to keep paint and other materials from causing damage.
You may wish to also wear protective clothing on your body and head.
Prepare the PVC Pipe
Before applying materials that will mimic cast iron to the PVC, you must prepare the pipe for the treatment. To give the plastic a somewhat more worn and "natural" appearance, slice it up a bit with a utility knife to make nicks and scratches that will show under the treatment.
Once you've finished with that, dust off the pipe so that the treatment will better stick to the PVC. Then apply a layer of primer to the pipe. Without this, the cast iron treatment will not stick to the PVC well.
Apply a thin layer of black, oil-based paint to the primed PVC. If you wish to make the pipe look older and rusty, consider using some rust-colored paint as well.
Before this layer dries, rub some thin sand into the tacky paint to provide a rough texture similar to that of cast iron. You may want to look at pictures of cast iron pipes to get an idea of the look you're going for. If you've added rusty areas, make them look rougher with more clumps of sand. Allow this second layer to dry completely.
When the textured layer is dried, add another layer of just the black, oil-based paint to cover any excess sand. Allow this layer to dry completely. If you spread the sand and paint evenly, your exposed PVC should now resemble cast iron.
If you added rust-colored paint underneath, use some sandpaper to wear away at the fresh black paint, allowing some of the rust to show through. Depending on how this works out for your individual project, you may need to add more sand and black paint to some areas.