Thread seal - how long to wait?

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E

essayer

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Sep 18, 2021
22
U.K.
Pool Size
15000
Surface
Vinyl
Chlorine
Liquid Chlorine
Replacing my multiport today and applied liberal amounts of thread seal (rectorseal) to the threaded fittings from pump / outlets etc

I did thick coat of seal, turned hand tight and quarter more. That seemed tight enough, any more I’d be worried about cracking it.

After six hours switched on it and quite literally jetted a thin spray of water out the pump fitting! And outlet was dripping too.

Did I not leave long enough to set? It’s warm here today, I’d assume it would set within a few hours.. no? I’ll try again tomorrow with ptfe + seal together
 
No wait time on "pipe dope" (rectorseal is a good one). It literally never sets up.

While you are very wise not to overtighten, it sounds like you didn't get it applied evenly.

I would remake that joint by taking it apart and cleaning as much of the seal off with a rag that I could. Next the sealant works best if both male and female are "doped" evenly. You really don't need a lot.....just complete coverage on both sides.

After you hand tight......try to REALLY hand tight but do not use a wrench. On those fairly large pipes, I think you can do all that's needed by hand. If it still leaks, you have to judge whether or not to put a wrench to it. I typically don't but my "hand tight" is close to all I can give it.
 
Well I redid both.. good news is one doesn’t leak!

I measured (dry) number of turns before completely hand tight, then did two/three turns of PTFE, then pipe dope liberally. Same number of turns, resisted the urge to tighten more.

But.. the other leaks. A drip or two per second. I’ll try again tomorrow with three/four turns PTFE, but don’t want to crack the fitting.

I’m wondering if the threaded male end (a union) could be damaged somehow. Is that possible?

I’ll get there in the end :D
 
From the lasko site (Link at the bottom). I use Plasto-stick as recommended by Pentair/Stay-rite for their multiport valve. It is non-hardening, compatible with plastic and doesn't add slipperiness. Never had a leak with this.


Don't use Teflon tape, Teflon paste or pipe dope. Do use a sealant.

Teflon tape, Teflon paste and pipe dope is intended for metal pipe and fittings. Metal to metal fitting joints are more difficult to tighten than plastic; the surfaces tend to gall without the aid of such lubricants as Teflon or pipe dope. Plastic fittings do not need this lubrication.

When Teflon tape is wrapped around plastic male threads it adds to the strain and tensile stress. The tendency of most installers is to incorrectly wrap several thickness of tape around the male threads, increasing stain and stress further.

Teflon paste and pipe dope, just like Teflon tape, make threaded joints slippery. Their use on PVC fittings can be an invitation to over-torque.

When working with threaded plastic fittings do use a proper sealant. The right sealant for threaded joints is non-hardening, compatible with plastic and doesn't add slipperiness.

Assembling Threaded Plastic Fittings | LASCO Fittings

www.lascofittings.com www.lascofittings.com
 
Plastostick looks interesting but I might struggle to get hold of it in the U.K., I’ll check out la-co suppliers as nothing comes up on a search. Reviews certainly look promising.

I’m using slic-tite so I’ll give it another try on its own tomorrow, I’m really reluctant to keep putting more ptfe on but can’t see many other options. I’ll get a new union as well, can’t hurt.

Thanks both
 
A lot of people will disagree, but I use Teflon tape and aquarium grade silicone and it works pretty well for me.

Before adding Teflon tape, screw in the fitting to see how tight it is and add enough tape so that it will create a snug fit as it is screwed in.

I would use 4 to 8 wraps of Teflon depending on the snugness of the fit.

Wrap the Teflon tape clockwise.

Then add the silicone and screw it in.

Multiport valves are made of ABS, which is brittle and easily cracked if you tighten too much.

Pump threaded fittings tend to be much stronger and typically looser than other female threads, so more wraps of Teflon can be used.


1653261124316.png
 
If you only use Teflon tape, it almost always comes loose and leaks.

If you don't use tape and only use sealant, it can leak especially if the fit is loose.

In my opinion, you want some tape to make the fit snug and some sealant that sets up without getting solid.

This helps lock it in but you can still take it apart if you need to because the tape separates the fittings from getting locked together by the sealant.

If the multiport fit is already tight, you can skip the Teflon tape and just use the silicone and let it dry before pressure.
 
I give up for another day! I tried 4 wraps, no wraps, still the leak. What’s weird is it’s always from the 1 o’clock position; I tried tightening, loosening, always weeps water from the same place. I’m going to take the mpv off again and inspect the thread in case something’s stuck in it, maybe a bit of sealant or something.

The male end of the union is seated solidly against the base of the female thread, so I’m not tightening it any further! Maybe I could stick an o-ring in there..
 

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If you have tightened the male fitting until it stops the fitting is damaged and possibly the pump. You should always see about three threads exposed in a properly tightened fitting. Pipe fittings are tapered and "expand" as they go into the female threads.
Six tight wraps of Teflon tape and a bit of silicone sealant has worked for me for decades of installations.
 
This is a multiport - brand new, not cracked.

There's 7 threads total on the union, which is one of these:
www.h2ofun.co.uk

Swimming Pool Male Threaded Union 1.5 Inch White PVC - Pack of 5

Threaded Union MT/FP - Pack Of 5 White ABS Socket Accepts 1.5 Inch Pipe Longer 50mm Thread 1.5" BSP In Stock For Immediate Delivery
www.h2ofun.co.uk www.h2ofun.co.uk
even dry I can easily screw in 6 3/4 turns and there's no threads sitting proud of the fitting

I wonder if the union is undersized or damaged somehow? I've ordered a new one just in case
 
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it's an Astral 00599 - one of these

Astralpool - Innovative Solutions for Pools and Wellness

Discover Astralpool, a leader in pool and wellness solutions. We offer a wide range of innovative products and high-quality services to create unique and sustainable aquatic spaces. Your well-being and comfort are our top priority.
www.astralpool.com

so if it's BSP .. and the union is BSP.. two parallel threads .. how would they ever seal without an o-ring?
 
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So my replacement union arrived and it is actually BSPT which functionally is like NPT in that the threads increase in size.

Fitted that and no drips after an hour, so fingers crossed we’re all good!

Thanks all for the pointers
 
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Well four days of SLAM and pump running 24/7, no drips observed so far!
Just a thin spread of slic-tite around the replacement tapered thread seemed enough.

Gluing on the replacement elbow for the filter return was THE most stressful thing ever.. no going back once I’d glued it but all good.

Now we just need good weather :D
 
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