Polyvinyl chloride (PVC) piping is acceptable for use in drain waste vent plumbing, and it’s use in these systems is widespread. One of the reasons for that is it is relatively inexpensive, lightweight and easy to join with simple tools. PVC pipe is joined together with PVC fittings using cement. Before the cement is applied a special primer is brushed onto the surfaces to be joined.
The rigidity and toughness of the type of polyvinyl chloride used in PVC piping requires treatment by a primer, which softens the material in order to improve the adhesion of the cement bond. It also cleans the pipe of grease and dirt.
In order for inspectors to verify usage of primer on plumbing joins, purple tinted primer is the industry standard for PVC pipe. The primer carries a few safety precautions to be observed during it’s application; it should not be breathed by pregnant women, and headaches are a common complaint. Latex gloves should be worn and you should have a good supply of spare rags nearby for wiping off drips, as the primer and cement are both pretty runny and messy.
Curing time for PVC pipe glue varies depending on temperature; at 30 to 50 degrees Fahrenheit, it sets in about 10 minutes, although time to total cure is longer. At 10 to 20 degrees F, the time to total cure is longer, up to 16 hours.
1. Cut the pipe tot the length required. For cutting PVC pipe, use a plastic pipe saw, holding the pipe in a miter box to ensure the cut is square. Alternately, a power miter saw with a carbide tip blade can be used.
2. Make two marks on the pipe- one indicating the end of the fitting when the pipe is fully inserted, and a second mark at a known distance to serve as a gauge after the first mark is covered up with primer and cement
3. With a pipe reamer, clean out the burrs from the inside of the pipe end.
4. Using a knife, bevel the outside edge of the pipe end to ease cement beading upon insertion
5. Apply a layer of primer to the outside of the pipe and the inside of the fitting, to the full depth of the socket in the fitting and the corresponding area on the pipe as marked off.
6. Apply cement to the fitting inside and pipe outside, while the primer is still wet. Generous amounts should be used, although not as much inside the fitting, to avoid cement puddles inside the joined pieces.
7. Join the two pieces, inserting the pipe to the full fitting socket depth. It is normal for excess cement to roll up against the pipe end and drip off the joint.
8. Hold the assembled parts together after joining; for small diameter pipe, hold for about 30 seconds, and for pipe of 4 inches or more diameter, hold about 3 minutes. This is to prevent the pipe slipping back out of the fitting while the cement sets up.
When joining PVC pipe, you will need to work fast in hot weather. The cement sets up faster at higher temperatures, so if you are not quick, you may not be able to insert the pipe to full depth or turn the fitting in the orientation needed before you cannot move it due to the cement drying.
One trick of the trade is to keep your fittings and pipe stored in the shade. If you have a helper, one person can apply the primer and cement and the other can assemble and orient the fittings.
In colder weather, however, heating up the cement with heat guns or hair dryers doesn’t work to speed up the drying time. In fact, it only causes the cement to bubble and blister, which makes for leaky joins. This means that you will need to hold the pipe and fitting together longer after assembling.