Threaded v. Slip Fittings

[dputt88]

So were about to purchase all of the fittings for our new tank and its going to be a couple hundred dollars just for unions and valves. So i started doubting my choice of getting all slip fittings that will be cemented to the pvc pipe because that stuff is fo life yo.... i started considering getting all threaded valves and unions so that they can be saved nd reused if i ever change the plumbing. of course i will cement some cheap thread x slip fiitings to the pipe and then attach the expensive valve or union. im assuming that threaded fitting are more prone to leaks when compared to

so pros and cons

slip fittings
-low chance of leaks
-cheaper
-cant repurpose expensive valves and unions

threaded fittings
-increased chance of leaks
-more expensive
-can repurpose expensive valves and unions

im not sure what i should go with...

 

[Kammetal]

I did not like threaded I had a bad experience. Every time I would tighten one area another would come loose. I just plumbed my tank and what I did was glue pvc to the bulkheads the and added a union. From there I started the more expensive plumbing. That way if I ever have to transfer or upgrade tanks all my expensive valves, pvc etc. wont be a waste

 

[Livinlocal]

In the past I have tried to use threaded pieces when I could, but they have always been problematic with salt creep over time. I’m not sure how often you relocate your tank/plumbing but I would just glue everything. It’s also worth the extra peace of mind knowing there’s no chance of any leaks.

 

[Crabs McJones]

So were about to purchase all of the fittings for our new tank and its going to be a couple hundred dollars just for unions and valves. So i started doubting my choice of getting all slip fittings that will be cemented to the pvc pipe because that stuff is fo life yo.... i started considering getting all threaded valves and unions so that they can be saved nd reused if i ever change the plumbing. of course i will cement some cheap thread x slip fiitings to the pipe and then attach the expensive valve or union. im assuming that threaded fitting are more prone to leaks when compared to

so pros and cons

slip fittings
-low chance of leaks
-cheaper
-cant repurpose expensive valves and unions

threaded fittings
-increased chance of leaks
-more expensive
-can repurpose expensive valves and unions

im not sure what i should go with...

Why not both? What I did with mine was used slip fittings in spots where I know I won't need to get at in the future, but put threaded fittings where I know I would need then for disassembly. For example, my bulkhead fittings are threaded so if i ever need to remove the bulkhead I can. But the 45 and 90 degree bends in my tubing are slip fit with unions between them

 

[JoshH]

Threaded fittings won't leak if installed properly, now in saying that they are a little trickier to install. It's important to remember that even slip fittings can leak if not glued properly and fixing a leaking slip fitting is infinitely more difficult than a thread fitting. I second crabs, using both is an excellent choice and it also gives you the most selection when it comes to fittings. I have both on my set up and they perform flawlessly.

 

[LadyMac]

This is interesting cause I too had wondered which to use.

 

[don_chuwish]

Like crabs suggested, I used threaded wherever I thought it might come in handy. In my ignorance at the time, I used either teflon tape or RectorSeal goop on the threads. Both worked fine but I've since learned that LA-CO Plasto-Joint Stik is the way to go. Don't over tighten!
With many of the expensive valves with true union fittings you can also replace just the fitting and not the whole valve if needed.

 

[JoshH]

I used either teflon tape or RectorSeal goop on the threads. Both worked fine but I've since learned that LA-CO Plasto-Joint Stik is the way to go. Don't over tighten!

Solid advice, not using a proper PVC thread sealant is the #1 reason for leaky joints along with overtightening. When using a thread sealant I applied a good amount in a ring on the inside of the female threads and screwed the male thread in till snug then gave another 1/4 turn and left it like that.

 

[Reef-junky]

You know a valve wouldn't be lost with slip fittings if you put unions before and after.

 

[Smo]

Like crabs suggested, I used threaded wherever I thought it might come in handy. In my ignorance at the time, I used either teflon tape or RectorSeal goop on the threads. Both worked fine but I've since learned that LA-CO Plasto-Joint Stik is the way to go. Don't over tighten!
With many of the expensive valves with true union fittings you can also replace just the fitting and not the whole valve if needed.

+1 on Plasto-Joint Stik. I will never use Teflon tape again on a plastic thread. Reliable and never hardens so you can disassemble if necessary.

 

[dputt88]

You know a valve wouldn't be lost with slip fittings if you put unions before and after.

Getting a little too expensive there.

 

[dputt88]

I ended up going with slip for almost everything, my gate valve will be threaded, I couldn' wrap my head around cementing at $50 valve. All of the other valves were $12 so they get cemented. Why doesn' every manufacturer make replacement slips for their true union ball valves. Save us a little money.

 

[JoshH]

Save us a little money.

Well you answered your own question lol but hopefully you ordered a few extra fittings, that was my biggest issue is I changed my plumbing plan slightly when I had it set up and didn't account for that in my ordering so I had to order more and pay out the nose for shipping. Also a few extra fittings gives you the chance to practice your gluing technique

 

[Reef-junky]

Getting a little too expensive there.

You can get them at menards.

 

[Chuk]

I went all glued with slip unions to be able to remove each section off the manifold

 

[ReeferBob]

Also take a look at PVC compression fittings they are awesome if you can incorporate them into your plumbing plan. And threaded will almost always leak at some point I would always go slip especially with bulkheads where it is a HUGE deal to try to replace if you have a leak issue.

 

[bblumberg]

I went threaded on my first salt water build. No real leaks for the 10 years it was in operation, but I did have a fair amount of salt creep around the threaded areas. My new builds use glued joints wherever possible, but with unions to allow parts to be removed for cleaning as needed. For all 3 newer tanks, I built manifolds for the returns so that I could run reactors of various sorts off the main return pump. The manifolds have gate valves, all of which have threaded outputs to allow me to mix and match the type of tubing they are connected to.

One major caveat I found was that Spears unions are easy to remove and reinstall (i.e., disconnect and reconnect the pipes), whereas the more expensive, but lower quality unions from the big box stores leaked after a few removal and reinstalls, necessitating their removal and replacement with Spears unions.

 

[cracker]

I just use a little teflon tape on threaded fittings.

 

[pledosophy]

I prefer threaded so you can take them apart later for cleaning. Every few years it is necessary to clean the pipes of an aquarium IME.

 

[Gridlock]

I went slip fittings with the primary plumbing and manifold. I used threaded fittings any place I might need to disassemble, such as the output fittings from the manifold.

I decided against threaded because there is really no need to disassemble the whole thing once it's together. Just be sure to use both PVC Primer and PVC Glue.