# pvc glue / primer vs. multi purpose cement



## Rain_Frog (Apr 27, 2004)

I was told by glass-holes.com that multi-purpose cement is stronger than PVC glue / primer when joining bulkheads to pvc.

Is this true? What do you guys use?


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## melas (Oct 24, 2007)

Rain_Frog said:


> I was told by glass-holes.com that multi-purpose cement is stronger than PVC glue / primer when joining bulkheads to pvc.
> 
> Is this true? What do you guys use?


I think it's a moot point . . . PVC glue is actually a solvent and will chemically weld the two pieces of pvc together. It would take *EXTREME* forces to break the weld. I always used PVC cement/primer for all of my fittings on my reef tank. Never had a problem.

*edit* It just came to me that most bulkheads are made of ABS plastic rather than PVC. In that case a multipurpose cement would probably be stronger. Either way - I've always used the pvc cement without issue . . .


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## Ed (Sep 19, 2004)

Unless you are using high pressure pumps on the system or there is a risk of really banging it around, there isn't any worry about the pvc glue. 

When I put system together if the water flow is going to be passive, (no pressure other than atmospheric) I often don't use pvc glue and just dry fit them. If I am running a pump or its in a location where its likely to get banged around, I always seal it. 

Ed


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## pl259 (Feb 27, 2006)

I don't know if it's true or not, but doing a test build with like materials could give you the confidence you're looking for.


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## Rain_Frog (Apr 27, 2004)

Do you guys think multi-purpose cement is pretty much frog safe? Glass-holes.com said it should be aquarium safe when it cures. But, I thought I'd get a second opinion.


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## MeiKVR6 (Sep 16, 2008)

Just use the PVC glue. It holds against the bulkheads fine.


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## frogfreak (Mar 4, 2009)

Are you joining two different materials?


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## Rain_Frog (Apr 27, 2004)

bulkhead is ABS plastic, while PVC is PVC.


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## Ed (Sep 19, 2004)

At work unless they are installing a heavy duty pressurized system, they (the plumbers) use pvc cement..


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## Rain_Frog (Apr 27, 2004)

I went to Home Depot and bought Oatey purple primer and clear PVC cement. Any pointers how to use this stuff properly? I read that you need to apply it quickly because the stuff welds fast.


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## DizzyD (Sep 19, 2006)

try to be neat w/ the primer, b/c it stains everything. Once that is applied to both parts of the "joint" (I try to make sure I get the actual end of the pipe as well as the outside) you're ready to glue. You don't have to go at warp speed to glue, but you should move quickly. I'd lay out all my parts in order, prime what needs to be primed, then start glueing (sp?). Give it some time to cure and perform a complete test before you finish the tank. Leaks are bad. Good luck it's gonna be a snap. Honest.


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## frogfreak (Mar 4, 2009)

It also helps if you dry fit everything and make a small mark with a pencil on your fittings on how you want them to line up. That way there's no guessing


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## DizzyD (Sep 19, 2006)

Ah, that part slipped my mind. good point there frogfreak!


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## MeiKVR6 (Sep 16, 2008)

frogfreak said:


> It also helps if you dry fit everything and make a small mark with a pencil on your fittings on how you want them to line up. That way there's no guessing


Do that before priming... After priming the pipes can sorta stick together and be difficult to seperate - even before gluing.


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## insularexotics (May 3, 2005)

Doug,
As mentioned, premeasure, cut and dryfit everything before priming or gluing. Prime the joints and let the primer dry. Then glue one joint at a time. Apply a thin layer of cement to both sides of the joint if at all possible. As you push the pieces together, it is best to give about 1/4 turn. This helps elminate air voids which can lead to leaks. As you push the pieces together (turning them) you should HOLD them together for about 10-30 seconds, depending on the size of the pipe, the tightness of the fit, and the amount and type of cement. As the solvent reacts with the PVC it can actually push the pieces apart, creating a weak joint. Lastly, have lots of rags or paper towels handy. After holding the joint, use a rag or paper towel to wipe the excess cement from around the joint. While it is not necessary for a proper joint, it sur edoes look neater and more professional. Better yet, pay me to come out and do it for you in frogs!!! 

If you are hard plumbing pumps, filters, or other compnents that may need to be removed from the system for maintenance or replacement, consider using a valve and union to isolate the component and make it easy to remove. Better still, use a true union ball valve. more expensive, but looks better and is easy to work with, IME.

Good luck!
Rich


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## Rain_Frog (Apr 27, 2004)

This is going to sound weird (obviously, I have never used this stuff before), but am I supposed to wipe / rinse the primer off the pipe BEFORE I put the PVC cement on? I know the primer is supposed to "clean" PVC. 

Or, just put primer on-- let dry-- and then use cement?


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## Boondoggle (Dec 9, 2007)

The primer dries pretty quick..and yes, it will try to get everywhere.


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## Rain_Frog (Apr 27, 2004)

I put some primer on, and it got everywhere on the PVC pipe. Is this stuff toxic if not coated with PVC cement? I cannot coat inside the PVC pipe easily to cover all of the primer.

I'm really cautious about any type of chemical that could come into contact with my frogs.


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## Ed (Sep 19, 2004)

Hi Doug,

As long as you let it dry before exposing your frogs to it, it is fine. Just don't dip the frogs in the liquid... 
here is the MSDS for the liquid 

http://www.herchem.com/msds/MSDS62_PVCCPVC_pur.pdf

Ed


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## insularexotics (May 3, 2005)

Doug, 
We use the stuff on fish and corals with no ill efects once it is dry. So I would not be worried about frogs. Always best to let it dry thoroughly before running water thru. Then it's a good idea to fill the system, run it for an hour or two, then dump and refill to flush any residue out. But I have primed and glued pipe in occupied systems where I couldn't flush and had the system running within two hours with no issue for the fish, corals and other inverts. If you can't smell solvent, you're good. Even when you do smell some, the water usually dilutes it sufficiently to take car eof issues. If you want to be uber-conservative, you could run some activated carbon in the system to catch any stray VOC's.
Plumb away my man!
Rich


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