On Mar 21, 12:09 am, albee wrote:
On Wed, 21 Mar 2007 00:30:48 -0500, albee wrote:
I'm installing a new pool filter, and I'm connecting a male pvc pipe
into the plastic/fiberglass? body of the filter (female connection).
I'm using a union (I think that's the term) so that I can screw a male
end into the filter separately from another female piece that I screw
onto the pvc pipe. I then have a ring which attaches these two pieces.
Frankly, while I thought it might come in handy, I also didn't know of
any other way to attach the filter (kind of hard to turn it around the
pipe, which is fixed).
Anyway, the real problem is that the male end which I'm screwing into
the filter leaks. I initially wrapped it 1-2 times with teflon, which
I later read wasn't enough. I did three wraps now, and it leaks less,
but still some. Should I do more? Or is there another thing I should
be trying, such as an O ring? Or plumber's dope? Or try another union?

Okay, in doing further research...

I've found that for 1 1/2" pipe, I should be using a heavy-duty teflon
tape. But aside from that, that teflon tape isn't meant as a sealant,
except for tiny deficiencies in the threading. My leak appears to be
bigger than that. Don't even know if my threads are tapered in order
to provide the necessary waterproof seal (just learned about that
"Duh" factor!). If they aren't, though, should I then be using an O
ring? And if they are, what else could be the problem? Thanks.

Yes, the teflon tape and dope are not there for sealing, they are
lubrication although as you say there may be some minor sealant
properties.

Standard PVC fittings have standard pipe taper threads. Do not
overtighten a male PVC into a female PVC as you can break the female
portion. That is the only failure I ever had with PVC (split on the
casting seam) and I have used a bunch of it.

If it is a very minor leak, i.e., a slow drip it may seal itself from
minerals in the water over time.

Harry K