PVC Glue & Primer For Swimming Pools
The the world of swimming pool plumbing systems you should bee using PVC, either flex or rigid, for all applications - both below grade as well as on the equipment pad. Using the wrong plumbing material will result in early failure of the system, usually from advanced oxidation due to chlorine reacting with the plastic material. Be sure you have read the section on pool pipes to learn more about which materials are safe to use for swimming pool plumbing systems.
Gluing PVC is a two step process using a primer followed by a PVC glue. The primer strips an impurities from the pipe as well as chemically softening it to prepare for the solvent welding glue application. Many inexperienced pool technicians skip the step of using primer since the glue by itself would appear to make a solid connection however this is certainly a bad idea. Without properly priming the pipe a glue joint will feel strong in your hands, but with some channel lock pliers you can easily tear apart the glued connection long after it has dried. When PVC is primed before gluing, and after the initial set of the glue, the welded connection is as strong as the pipe itself and can not be twisted apart by any means.
PVC Primer For Swimming Pool Plumbing
Purple primer is suitable for easy visual inspection of your glue joints
When plumbing in trenches, during rough-in, or for any underground PVC application using the purple primer as shown here will ensure that you can visually inspect every primer joint before using the PVC glue. The primer should be applied directly before the glue is applied, waiting just long enough to prevent any pooling of the primer in the socket end of the PVC. A small amount of residual moisture from the primer is OK but be sure to let any excess primer drip off the fitting before applying the PVC glue.
Clear primer is suitable for a clean looking equipment pad installation
Since the purple primer is a deep royal purple and will stain pretty much anything it touches, including you, using a clear primer for the pump room and equipment installation will help to keep your installation looking clean and neat (as well as avoiding the potential for spilling a full can of purple primer on your equipment pad). Both the clear and purple primer do the same thing and either can be used for both applications however missing a primer joint underground because you were using clear primer is certainly a problem that you do not want to have.
PVC Solvent Glue For Swimming Pool Plumbing
Gray PVC solvent glue is the strongest of all the PVC colored solvents
Gray "711" heavy bodied PVC solvent cement as shown here is the strongest PVC solvent welding glue available. Of all glue options, the gray is the only one that has PVC in the glue itself, making the strength of the connections stronger than with any other color option. Medium set refers to the amount of time it takes for each glue joint to set and a medium set will set to holding strength in 10-30 seconds depending on ambient temperature and the diameter of the pipe you are working with.
Clear PVC solvent glue is ideal for pool equipment installation
Clear "705" PVC clear solvent glue is useful for pool equipment installations as this allows for a very clean and neat looking equipment pad. A skilled hand can make purple primer and gray glue look good however clear primer and clear glue will make your equipment installation look top notch. The only disadvantage is that you need to make all of your primer and glue joints carefully to avoid any accidental leaks.
Flexible PVC requires a special glue for underground applications
"795" Flex PVC solvent cement is the product made for flexible PVC solvent welding. While you can use a product such as 705 or 711 for flex PVC it is not recommended to do this for burial applications. If there is ever a problem with the weld a buried connection can be very difficult to diagnose and repair. If you are plumbing in a new pool or installing a line below grade with flex PVC then this is the glue that you should be using.
Wet R Dry PVC solvent cement is blue in color and designed for damp conditions
Wet R Dry "725" PVC solvent cement is designed for damp conditions as experienced with swimming pool repairs to existing plumbing systems. All other forms of PVC solvent cement are easily compromised by the presence of water or dampness. Not designed to be used in wet conditions such as driving rain but more so where the presence of dampness can not be completely controlled.
Heat rated PVC is called CPVC and requires a specific orange color solvent cement
CPVC is chlorinated PVC and is light gray in color, most commonly used for going into and out of pool heaters. CPVC is also common in commercial swimming pools where heat rated pipes are a code requirement. CPVC solvent cement is orange in color and requires either clear or purple primer just like regular PVC pipe does. Since CPVC costs at 10 times as much as regular PVC many pool systems do not incorporate CPVC - however if you have a problem with melting pipes near your heater then CPVC is the answer you are looking for.
Green transition cement is one way to connect PVC to ABS in pool plumbing systems
Traditionally in plumbing systems you should not connect ABS to PVC. In the pool industry sometimes you are forced into making a connection like this as a result of some products being made of ABS such as some skimmers and some valves that are common in the industry. For these applications the best you can do is to use a transition cement such as this "794" transition glue however it should be noted that transition glue is not rated for pressurized applications. Still, using this transition cement would be the lesser of two evils as most PVC solvent cement will not properly adhere to ABS.
ABS glue is yellow (or black) and does not require primer
ABS is not suitable for swimming pool installations and so you should never find yourself using ABS "771" glue on a pool system. ABS and yellow cement are not suitable for pressure systems as well as ABS not being compatible with chlorinated systems.
Now that you know which glue and primer you will need be sure to read all of the sections on how to install pool equipment and make your equipment install as good as possible.