OK, so me and plumbin’ don’t get along so well…
…but I usually manage to get it in the end. This one has me stumped.
Installing new PVC irrigation valves. Supply side is 3/4″ female pipe thread. So I got PVC male pipe thread to 3/4″ female slip PVC fittings. Followed my standard approach – 3 or so wraps of teflon tape & screw the fitting on, reasonably tight but not enough to split the fittings (I think). 6 out of 6 valves leaked at that fitting.
Round 2: take it all back apart, replace male fitting with 3/4″ PVC nipple, then into female thread by female slip fitting – just like the other valves here. Oh yea, used Rectorseal Tplus2 on the recommendation of the crusty old pro at the hardware store. Tightened to hand tight plus a half turn or so. Now only about half are leaking. WTF???
The only thing I can come up with is that I’m over-tightening. What is the standard for PVC to PVC threaded fittings? Any other suggestions?
Wayne
Replies
If these are standard PVC fittings no pipe dope or other sealant is recommended.
I always just give them a good tightening, not enough to break anything but good and tight...
Yeah, what Abm said, no tape or dope on pvc-to-pvc.
When I was learning these things, I was told that taping or doping plastic threads actually keeps them from sealing, as you are seperating the planes that ming engage in a like-on-like mating. Plastic threads also being cut to a slightly different specification than metal ones, as well.
Wor irrgation fittings, I aim for "stong" hand tight, then only (caustion highly technical term here) a "squidgen" more (this, of course, assuming that the fitting has threaded all the way on--easy to see at eye level, less so, half under a sidewaly in the bottom half of a muddy trench).