Tap to thread PVC?

[mlb75]

I'm getting ready to finalize some updates to my return plumbing and would like to tap a feed line for my carbon and GFO reactors off the main return but don't want a huge T and step downs etc to go from 2" to a 1/2" push fitting.

What I was thinking is to drill and tap the 2" PVC and thread in the John Guest valve. I'd intended to use regular sch 40 pipe but could use sch 80 to get the additional wall thickness if necessary.

Any con's to doing that?

 

[der_wille_zur_macht]

It'll be hard to get a good seal.

Pipe threads are tapered, the idea is that they pull themselves tight as you thread them on, to help seal the thread. In a curved surface, it'll be hard to get even tension all the way around. Depending on the diameter differences, there may not even be any contiguous threads around the hole, so it may be impossible to seal. You might get it to work by (improperly) using teflon tape or something but I wouldn't count on it.

If you really can't use a tee, I'd consider redesigning the plumbing. Or try a uniseal, I'm pretty sure they go down to fairly small diameters and are a much better bet at sealing against a curved surface than a threaded fitting.

 

[outy]

I would put a T on the new outgoing line put a cap in and have my JG fitting epoxied into the cap. Makes for a clean attachment.

You could thread it in like your planning to do and just use lots of epoxy after sanding the pvc to rough it up, or you wont get a bond.

 

[grizzly123]

I'm getting ready to finalize some updates to my return plumbing and would like to tap a feed line for my carbon and GFO reactors off the main return but don't want a huge T and step downs etc to go from 2" to a 1/2" push fitting.



What I was thinking is to drill and tap the 2" PVC and thread in the John Guest valve. I'd intended to use regular sch 40 pipe but could use sch 80 to get the additional wall thickness if necessary.



Any con's to doing that?

I've tapped 2" multiple times for exactly the purpose you are doing. Worked fine for me. Used a npt tap.

 

[JTL]

Tap it and if it leaks put some 2 part marine epoxy around the fitting.

 

[mcgyvr]

While it may work the information provided by der_wille is still valid/true..

If one was to side tap pipe they would typically use a "tap saddle" to negate the issues that der_wille was implying.. or with metallic pipe a boss may be welded on,etc...

 

[Zephrant]

It's possible to cut a couple in half length-wise, sand out the remaining rib, and pvc glue it to the pipe to give you a double thickness to drill and tap.

But I typically put in a tee and end cap, and drill the end cap.

 

[RobZilla04]

This has bad idea written all over it...

 

[mcgyvr]

This has bad idea written all over it...

"less than optimal" IMO.. I personally would do it if I absolutely had to but I would likely do a tee/cap instead..

If one was overly critical and a perfectionist then you wouldn't do it.. But IMO if drilled/tapped properly you can surely come out successful..

 

[Ted_C]

Here's how you're actually supposed to get a reactor feed from your 2" return plumbing:
2" x 2" x 1" Tee (1" is outlet)
https://www.pvcfittingsonline.com/2...ing-tee-socket-x-socket-x-socket-401-249.html

1" Slip to 1/2" threaded Bushing:
https://www.pvcfittingsonline.com/438-130-1-x-1-2-schedule-40-pvc-reducer-bushing-flush-style.html

1/2" MPT to 1/2" John Guest (Push to Connect) fitting
https://www.supplyhouse.com/John-Gu...vd7sIFBzzJUYnKshiYnz9mDdNY9uMktgaAonkEALw_wcB

Here's a view of what that looks like in my tank (except I'm using 1" instead of 2" on a sump re-circulation pump).

 

[slief]

In all honesty, I would not drill and tap the 2” line. That line is under pressure and if god forbid there is a leak, it could be catastrophic. I don’t think it’s worth it. Plus, if you had to glue the JG fitting and and it ever had an issue, you would have issues replacing it. I just don’t think its worth the risk to save an inch or two. Plus, there are better solutions for what you are trying to do.

Why not use something like this PVC manifold. Just put a threaded bushing into the 3/4” lines for your John Guest fittings.
https://www.amazon.com/dp/B0039B9XPU/

Or this:
https://spacare.com/PVCManifolds672...MIkej04OCJ2AIVDdlkCh22twT0EAQYGyABEgJjBPD_BwE

Here is a very good selection of 2” PVC manifolds.
https://flexpvc.com/cart/agora.cgi?product=PVC-Manifolds

 

[Arthur1]

MLB, I've done all types of pvc plumbing on aquariums, including tapping/threading. I'm a perfectionist, enjoy trying new thing (tinkering) and have ocd. I'd personally put in a T as recommended, reduce it down and use a true union ball valve with a barbed fitting after. Then enjoy. For what its worth, I hope that helps.

 

[JTL]

Here's how you're actually supposed to get a reactor feed from your 2" return plumbing:
2" x 2" x 1" Tee (1" is outlet)
https://www.pvcfittingsonline.com/2...ing-tee-socket-x-socket-x-socket-401-249.html

1" Slip to 1/2" threaded Bushing:
https://www.pvcfittingsonline.com/438-130-1-x-1-2-schedule-40-pvc-reducer-bushing-flush-style.html

1/2" MPT to 1/2" John Guest (Push to Connect) fitting
https://www.supplyhouse.com/John-Gu...vd7sIFBzzJUYnKshiYnz9mDdNY9uMktgaAonkEALw_wcB

Looks great! When are you going to fire it up? I love new sumps.

Here's a view of what that looks like in my tank (except I'm using 1" instead of 2" on a sump re-circulation pump).

 

[Kevin Guthrie]

Buy a 2 inch PVC cap. Tap the flat end, not the pipe, and cement the cap to the pipe.

 

[Jaggerz]

Tapping pvc pipe is a non issue. It will be fine. I’m a machinist by trade and have done much sketchier things without issue. One product I’ve been involved with for several years has 1/2” npt threads in .1 thick stainless steel. That’s just about 1 1/2 threads really less once both sides are chamfered. They seal . As far as npt in pipe goes. It’s done all the time.

 

[der_wille_zur_macht]

Buy a 2 inch PVC cap. Tap the flat end, not the pipe, and cement the cap to the pipe.

If you are going to go through the trouble of tapping a cap, why not just get a slip x female threaded reducing bushing? It won't take up any more room than a cap and avoids the hassle of having to cut threads.