Plastic pipe for DIY plumbing project
Q. I am renovating an older house and am totally redoing the kitchen and bathrooms. I plan to do the plumbing myself. Since I cannot solder copper pipe, can I just use plastic pipe throughout?
Erika K.
A. Plastic pipes can be used throughout your remodeling projects. Although it can be a somewhat time-consuming task, it definitely is a do-it-yourself job. You are going to have to use several types of plastic pipe materials to do the entire job. For no-pressure drainage DMW (drain-waste-vent) lines, white PVC (polyvinyl chloride) pipe is commonly used.
Rigid CPVC (chlorinated polyvinyl chloride) plastic pipe is used for hot and cold water supply lines. Check the printing on the pipe to make sure it is CPVC. Also, it often is beige instead of white to make it easier to distinguish from drainage PVC pipe. Gray BU (polybutylene) pipe also is sometimes used for the supply lines.
The components of a residential plastic plumbing system can be connect by solvent welding or with mechanical fasteners and couplings. For PVC and CPVC pipes, solvent welding is usually used. It is very simple to glue the pieces together without leaks. The mechanical couplings are typically used with the flexible BU pipes. Using the couplings does make it easy to remove or change things at a later time.
Solvent welding is used for many types of plastic assembly in addition to plumbing. The solvents melt the surface of the plastic breaking down the long chemical chains. When the chains reform across the joint as the solvent evaporates, the two pieces are bonded together.
Although most pipe material should be similar, it is a good idea to purchase it all from the same suppliers to insure the pipe and fittings are of the same material. This also makes sure the parts fit together with the proper clearances for the strongest solvent weld joint.
Plastic piping is durable, but there can be flaws at times, especially near the ends. Inspect the pieces for cracks or scratches. Don't use an pieces with even fine cracks. A small scratch should fill in well enough when the solvent is applied.
It also is important for the end of the pipe to be cut off squarely so it seats completely in the fittings. If it is not, use a hack saw, or better yet a special plastic pipe cutter, to square up the end. It sounds as though you will be doing a lot of pipe cutting, so it might be worthwhile to invest in a saw blade just for plastics.
You will find a burr around the edge of the cut pipe. Use a file or a utility knife on an angle to scrape it off. A tight fit between the outside of the pipe and the inside of the fitting is important for a good weld. Don't clean off the burr with sandpaper because you may take off more than just the burr.
Apply a primer/cleaner to the end of the pipe and to the inside of the fittings. Do not touch the surfaces after they are cleaned. Brush a coating of solvent on the end of the pipe and the inside of the fitting. Push them together, give them a slight twist and hold them for a few seconds.
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