Which diameter pvc doesn't float?

[mfinn]

I'm planning on removing all my fish ( 21) and putting them in a bare bottomed quarantine tank and was planning on using cut pieces of pvc pipe as cover/hiding places.
I saw a picture somewhere that someone made a pyramid out of cut up pieces of larger diameter white pvc pipe, in a holding tank. I don't remember where that is.
I tried that once with black abs pipe and found out it is extremely buoyant.
I know white pvc fittings don't float, but the larger ones are pretty expensive.
I was planning on getting a 10' piece of 4" diameter schedule 40 pvc pipe, but I am worried it might float too.
I did a google search and found a discussion on the matter. It was said 1/2" through 3" doesn't float, but 4" will.
I was wondering if anyone here has any more info on this or have already done what I'm trying to do.
Pics?

 

[JTL]

I cannot imagine a 4" open piece of PVC floating but admittedly I haven't tried it.

 

[Ted_C]

it may be the discussion you were seeing was a plumbers discussion - where the pipe is for sewage (and is mostly empty) and it would float in ground water. A cut piece of 4" with no air in it shouldn't float.

 

[mfinn]

it may be the discussion you were seeing was a plumbers discussion - where the pipe is for sewage (and is mostly empty) and it would float in ground water. A cut piece of 4" with no air in it shouldn't float.

It was on monsterfishkeepers.com

 

[Ted_C]

they are mis-informed then and/or referencing something different than PVC.

https://physics.stackexchange.com/q...re-denser-than-water-how-comes-they-dont-sink

 

[mfinn]

they are mis-informed then and/or referencing something different than PVC.

https://physics.stackexchange.com/q...re-denser-than-water-how-comes-they-dont-sink

I just went to my closest Lowes store and they didn't have any pvc pipe larger than 2".
I did find some a couple 4" tees and a 4"-90 for $10
I'll check the other stores. May just use a assortment of tees and some 3".

Most of my fish are small in height like anthias and wrasses and bassletts.
It will be interesting to see what I can build for a structure for the fish.
It only has to last 4 weeks.

 

[mfinn]

they are mis-informed then and/or referencing something different than PVC.

https://physics.stackexchange.com/q...re-denser-than-water-how-comes-they-dont-sink

Thanks for the help

 

[MrsReefK]

I have 4" Elbows in my qt and they sink. But it's white, I'm not sure if you want white from your original post.


Sent from my iPhone using Tapatalk

 

[HippieSmell]

Isn't the density of pvc the same, no matter the diameter? Why would one diameter float and the other not?

 

[mfinn]

Isn't the density of pvc the same, no matter the diameter? Why would one diameter float and the other not?

After some research and advice, there is a difference in pvc.
There is a solid core pvc and a cellular core ( cellcore)( newer cheaper?) pvc.
The cellcore floats.

I did find some fairly cheap white pvc 4" tees at lowes.
I will probably get a few of those and some 2" pvc

 

[ca1ore]

The 3" PVC pipe that I bought from HD floats .....

 

[der_wille_zur_macht]

It has nothing to do with diameter and everything to do with material as you discovered. Cellular pvc floats, it has a "foam" core instead of being solid. It is often used for exterior trim on houses and sometimes as pipe. All I've seen it as for pipe is DWV (drain waste vent) and isn't meant for pressure applications. It would work fine for plumbing a tank as we don't see much pressure, but it does float.

Ask in the store you're buying it for help. ASTM F 628 is the standard for foam core pipe. That will always be marked on any pipe that is foam core so you can just look for that and avoid it.