PVC threaded pipe sealant

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W

WorBry

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Nov 19, 2011
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I'm replacing some sections of PVC hose (1-1/2" tiger-flex) with PVC hard-pipe.

For the the pipe-to-hose connections I decided to use screw-in barbed hose adapters (with clamps), requiring terminal female thread PVC fittings on the hard-pipe. I've followed what I thought to be correct practice - applying a couple of rounds of teflon tape to the male thread, screwing-in to hand-tight and then two more turns with a wrench - but found that hand-tight barely got the thread in half-way and two more turns required quite some force and still left a gap of about a 1/4". Tried with just one round of teflon tape and didn't fare much better.

Seemed odd that fittings from the same manufacturer (Lasco) wouldn't completely screw together, so I checked their website and found they state that teflon tape should definitely NOT be used because it stresses the tapered threads and risks splitting the fittings....yikes !!! Nor should regular 'pipe dope' or teflon paste be used because they lubricate the joint and encourage over-tightening.

http://www.lascofittings.com/supportcen ... lastic.asp

The only thing they recommend is applying a non-hardening thread sealant compatible with PVC plastic.

Are other people following this advice? - the contractor who installed my pool certainly didnt - all of the threaded connections were heavily teflon taped - might explain the several cracked fittings and copious amounts of silicone I found when disassembling the plumbing.

Could anyone recommend a good, PVC compatible thread sealant?
 
http://www.permatex.com/products/automo ... ealant.htm

Screw straight adapter, using Teflon pipe sealant tape or Permatex No. 2, securely into pump discharge. (Do not overtighten.)
Screw elbow adapter, using Teflon pipe sealant tape or Permatex No. 2, securely into opening in control valve marked PUMP. (Do not overtighten.)
http://www.hayward-pool.com/pdf/manuals/manual50.pdf
Click to expand...
On threaded valve connections use only Teflon® tape, 100% Teflon® tape, 100% Teflon® paste, or Permatex® #2 to seal the threads.
http://www.pentairpool.com/pdfs/CleanandClearPlusOM.pdf
Click to expand...
 
OK thanks.

Just to clarify, it was the female 1-1/2" threaded PVC pipe adapters I was having particular issues with. No problem screwing male threads, whether that be pipe fittings, unions, nylon or poly hose adapters, fully into the filter and pump ports. In that case, teflon tape is definitely required for a tight fit, but, in view of Jason's comment, I might think about changing over to sealant if it works well with the female adapters, especially if it makes unscrewing threaded connections easier.
 
Thanks both of you.

The RectorSeal Tplus2 I can get locally, so I'll give that a go first. I assume it could also be used with a little teflon tape if necessary, like for the filter and pump port connections.

X-PertPool said:
You are not to expect to get all the threads to disappear when tightening.
Click to expand...
Ah, OK, I thought you did.

Thanks again.
 
The RectorSeal Tplus2 wasn't available locally after all, but I found the Permaseal #2 (gasket) sealant in the Auto section of Canadian Tire.

One question though. If used in combination with 1-2 wraps of teflon tape, is it really necessary to plaster the entire male thread with the Permaseal, as you would with less-expensive daub-on pipe thread dope, or is it sufficient to apply a bead of the stuff (since it comes in a tube) around the leading part of the thread and let the screw-action squeeze and spread it?
 
Well I'm glad I tested the Permatex #2 on some old pipe fittings first. This stuff is wicked. Black like treacle (although in the picture on the packaging it looks white) and not so easy to get off white pipe once it's stained.....not to mention your hands. Yep, I'd say applying a bead of the stuff is the way to go. I'll maybe use it on the filter and pump ports connections and with the black (poly) barbed hose adapters. But for the tighter PVC-PVC screw fittings I can see myself getting into a mess.

Short of finding the RectorSeal Tplus2 or Permaseal Pipe Thread Sealant with PTFE, (both of which are white), has anyone used Oatey's Great White Pipe Joint Compound in pool plumbing? It's stated to be suitable for PVC and is available in most hardware stores in my area. I'm just a bit concerned that it is stated to be lubricating.

http://www.oatey.com/Channel/Shared/Pro ... _PTFE.html
 

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Unfortunately, I can find neither of them locally. The only PVC compatible sealant the hardware and plumbing stores sell around here is the Oatey Great White stuff. The pool stores have nothing, only teflon tape. Wishing I'd taken the glued flex to PVC fitting route now. The wife is on to me to get the pool up and running this weekend :hammer:
 
Thanks, that's good to know, 'cos I've ending up using it on all the joints. A tech at the pool store had me going from pillar to post looking for Silicone GI which no-one had, and by that time I'd had enough.

Anyhow, so far so good, at least on the suction line.

On the return line I messed up. I was one screw fitting short and thought what the heck, I'll glue. In my eagerness to do it right (with the quarter turn) I got my markings mixed up and glued with the curve of the flexi pipe going the opposite direction. Typical !! I guess I could cut the hard pipe or flexi, fit a coupling and do it again, but that's more time lost ( and more :hammer: ).

I've read that flex can be straightened out using a hair-dryer or by placing in hot water. Thought it best to let the glued joint fully cure before trying, but what are my chances of curving the flexi in the opposite direction without ruining it?

Sorry, I know this is off topic, but I'm a man under duress :shock:
 
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