Making proper PVC repairs is essential for leak-free spa plumbing. Since flex pipe is used in hot tubs, the techniques are somewhat different than with rigid PVC plumbing.
Many hot tub plumbing repairs involve cutting out old plumbing fittings. New sections of flexible PVC pipe are then spliced in. Flex pipe comes in several standard sizes.
Besides rigid fittings and flex tube, you'll need PVC Medium Body Cement, PVC Primer, PVC Cleaner, and a cutting tool.
Cutting Flex Pipe
Flexible PVC pipe can be cut in a few ways. If you have one, an old-fashioned miter box and hack saw works well. A hack saw with medium size teeth, or a common wood saw will also do the job.
Home centers also sell or rent tools specially designed for cutting PVC tube. These are easier to use for making cuts in flex pipe already installed in a spa. Make sure the tool will handle the size of the pipe you are using.
The main thing to keep in mind is that a clean, straight cut is essential for the best cement joint.
After making your cuts, remove the burrs from the cut ends of the PVC pipe. Using a knife as a scraper, slide its edge sideways across both the outer, and inner edges of the pipe. After de-burring, the pipe will slide much easier into fittings to make a more positive fit.
When finished de-burring, wipe the pipe ends with a clean, dry cloth. If this is a section of existing pipe, wipe up any water present, inside and out.
Before cementing flex pipe to rigid fittings, it is essential to make a trial fit. The pipe should slip fairly easily into the fitting, approximately one third of the socket depth without much force.
Cleaning the Connections
Before priming or cementing, use PVC Cleaner (not to be confused with primer). Use the cleaner on both the male and female portions of the joint. This will remove residual films from new rigid fittings, and dirt and oils present on existing flex pipe.
The extra cleaning step is well worth the time for the best joints possible. This also allows for proper prep of the flex pipe, since primer is not recommended for flex.
After allowing a few seconds for the cleaner to dry, apply purple primer to the rigid PVC fitting. Using the dauber, apply the primer using a circular motion, covering all of the surface to be joined. This prepares the fitting with a little extra bite for a very strong cement weld.
Note: Spa flex pipe is a softer PVC which contains more plasticizers than rigid PVC elbows, couplings, etc. For this reason, we do not recommend the use of purple primer on flex hose. It can overly soften it, causing the PVC weld to degrade over time and possibly fail. Again, before using the cement, use PVC cleaner only on flex. Use both cleaner and primer on the rigid parts.
When the primer is dry, first apply medium body PVC cement to the rigid fitting. Spread an even coat using the dauber in a circular motion. You can now set this piece down (without worrying about cement touching your work surface).
Next, apply a liberal coat of cement around the perimeter of the spa flex pipe. Now grab the previously coated fitting with the other hand.
Immediately, push the flex pipe all the way into the fitting while turning about a quarter turn. Rotation distributes the cement evenly to assure a positive weld.
Don't let go yet! Sometimes pipe tends to bounce out of the fitting part way while the cement is still wet. Hold the parts together for a minute until the cement has bonded them.
Wipe off any excess cement and leave the joint undisturbed. Allow to dry for at least half an hour (one to two hours in cold weather). The cement weld should reach full joint strength and be suitable for use within 24 hours, depending upon temperature and humidity.
Clear vinyl tubing is often used for manifold plumbing of smaller spa water and air lines. These connections are not normally glued. Clear PVC tubing is available in from us in a wide range of sizes at the lowest prices.
"Your kit was priced right and had more than enough cement, primer, etc. to do the several repairs I needed. Thanks for the good products and great website instructions. The job was easier than I imagined and the hot tub is back in action."
Lake Mary, FL