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View Full Version : Do I need to glue or use sealants for PVC plumbing?



angeladay
07-12-2006, 12:01 AM
So, I finally gathered all materials needed to plumb my drilled tank. The question is, do I need to use any sealants/glue to to connect PVC pipes into bulkheads? One of the bulkheads is threaded.

Please help!

Oddball
07-12-2006, 12:12 AM
You can use teflon tape for the threaded fittings and PVC adhesive for the slip fittings. Once cured the adhesive becomes inert and is harmless to fish. If you want to set up your plumbing for ease of future disassembly, you can use threadded fitting throughout your plumbing and/or use PVC compression couplers.

dodgefreak8
07-12-2006, 12:24 AM
do yourself a favor and use glue. It won't harm your fish and is alot more reliable. Unless you plan on dismantling it later then use threaded or compression type fittings.. Also the wet set type of glue dries faster.

Tongue33
07-12-2006, 12:37 AM
I agree glue in my opinion is better.. Leaks can be nasty :)But i've seen happy campers with threaded fittings :)

angeladay
07-12-2006, 12:41 AM
Glue? What type of glue?

Oddball
07-12-2006, 12:53 AM
Glue? What type of glue?

Check your hardware store for PVC glue/sealer/adhesive/cement. You'll find it in cans with 1" screw tops for the applicator wand. I use the clear sealer which works on both white PVC and black ABS pipes/fittings. The cans look like this but, the labels differ depending on brand and application.

arlo
07-12-2006, 4:50 AM
yes use sealent. like if ure attatching a 90 degree elbow onto a staight pipe u should spread the sealent on the straight pipe first and then stick the elbow on. i made the mistake of trying to seal the piping after i had put everything together. doing it the latter way causes leaks, doing it the first way makes it bulletproof :naughty:

cockroach
07-12-2006, 4:57 AM
thanks now i also know how to do it.

Hasi
07-12-2006, 9:58 AM
I used PVC sealeant and it does no harm to fish once dried. Definitely need to glue the PVC pipes as water pressure will eventually bust from somewhere.

Steve_89
07-13-2006, 3:46 AM
Glue...seriously use it.

I've seen so many people regret not using it.

monte20
07-13-2006, 2:57 PM
Id go with the sealant. but if you already have the glue then use that. i only ssy sealant because its been tried and true for me for a long while.

dodgefreak8
07-13-2006, 6:20 PM
yes use sealent. like if ure attatching a 90 degree elbow onto a staight pipe u should spread the sealent on the straight pipe first and then stick the elbow on. i made the mistake of trying to seal the piping after i had put everything together. doing it the latter way causes leaks, doing it the first way makes it bulletproof :naughty:
I don't know what people are talking about by sealent but use PVC GLUE if you are using pvc nothing else.Well let me rephrase that you need primer and glue.. the primer will soften and clean the pipe and the glue will glue it.. there is nothing stronger or more leak proof that pvc glue on pvc.. trust me I'm a plumber and its the only thing that is guaranteed. Make sure you prime and glue both the fitting and the pipe.

CHOMPERS
07-14-2006, 4:24 PM
DodgeFreak, you da man :woot: I was going to say the same thing. I have plumbed for the swimming pool industry for years (new construction and repairs) and cleaner/primer is extremely important, as is treating both surfaces to be glued. Cleaner/primer will allow the parts to actually weld together. I have pealed joints apart that were only glued, but those that had cleaner or primer applied were as if a single piece.

note to those using new pipe: Cleaner is not just for old or dirty pipe. Cleaner and primer both break the molecular surface tension in the surface of the PVC and allows the glue to do its job. New pipe also has a layer of oil in the surface due to the manufacturing extruding process.

By applying cleaner/primer and glue to both surfaces, you should have a leak free joint 100% of the time. If you try to go cheap with the glue, you will have leaks. Be generous enough with the glue so that it pushes out of both sides of the joint. When you are done, your work area should be a glue and cleaner mess. You can clean the drips on your pipe with the cleaner brush if you feel looks are important.

Use caution with the fumes. They build up in large plumbing projects and stay there until you blow them out. I have come close to knocking myself out several times by breathing the concentrated fumes. And no it will not get you high... It will give you a migrane though.

dr_sudz
07-14-2006, 4:51 PM
I would aside from all the glue talk, use a lil silicone on the parts that are threaded. Particularly between the fitting and the glass. This will make a gasket that will be leak proof, and you can even do the threads themself. If you do the threads you can still undo them later if need be with out having to take a chop saw to the plumbing.

dodgefreak8
07-14-2006, 6:17 PM
I would aside from all the glue talk, use a lil silicone on the parts that are threaded. Particularly between the fitting and the glass. This will make a gasket that will be leak proof, and you can even do the threads themself. If you do the threads you can still undo them later if need be with out having to take a chop saw to the plumbing.
personally I would avoid the silicone all together.. Just use a teflon tape and pipe dope. together. Do the tape first and be sure to put it on the right way!!! you have to wrap the tape so that it is in the same direction you will be turning the fitting.. An easy way to do this is take the threaded end and point it at you now wrap the tape clockwise.. then add the dope.. Silicone is not as reliable as this method and this is way easier to get apart..as for the fittings that are in the glass they should come with a rubber gasket and silicone can actually deteriorate these seals making them leak.. these things are designed for a leakproof seal so trust them.

trae
07-14-2006, 6:25 PM
Good PDF for working with PVC

DOWNLOAD PDF:
http://www.box.net/public/ghtcle31o1

zennzzo
07-14-2006, 9:46 PM
...as for the fittings that are in the glass they should come with a rubber gasket and silicone can actually deteriorate these seals making them leak.. these things are designed for a leakproof seal so trust them.

Some bulkhead manufacuturers suggest a small bit of silicon grease to be applied to those rubber gaskets/o-rings so that when they are tightened they stay flat and don't bunch up creating an uneven seal...;)

dodgefreak8
07-14-2006, 10:49 PM
grease maybe but not the sealant

zennzzo
07-15-2006, 3:24 AM
grease maybe but not the sealant

Exactly...I can see where one might confuse the two...
Silicone Sealant is like an adheasive...
Silicone lubricant is like the grease I was refering to...
Good ol' Drs Foster & Smith got the good stuff right here...
http://www.drsfostersmith.com/Product/Prod_Display.cfm?pcatid=9708&N=2004+113828

CHOMPERS
07-15-2006, 8:25 AM
Wow! Talk about a literary mess...I personally do not use the term 'sealant' for PVC or for silicone. My language is limited to PVC GLUE and SILICONE RUBBER due to the local trade. I get the feeling that some of the posts here use the word 'sealant' interchangably for both PVC glue and silicone rubber, but I may be translating the posts wrong...

Silicone Rubber is the wrong thing entirely for slip (or socket) fittings. It is ok for low or no pressure threaded fittings. For high pressure applications, you can not beat DodgeFreak's recommendation of teflon tape w/ pipe dope. Myself, I prefer the teflon dope over the clay. I have just had better results with it.

Silicone Rubber comes in different grades for different applications. The cheapest silicone rubbers are unsuitable for plumbing but the higher end products will hold 50 psi if allowed to cure over night. To tell the difference between silicones takes experience in feeling the texture/thickness of the uncured product. A good quality silicone is much thicker than the bargain bin silicones. Boss products, GE 1200 series, and any aquarium silicone is good enough for threaded plumbing fittings. However, siliconed parts do not clean up after dissassembly like teflon tape and pipe dope.

Teflon tape by itself is a craps shoot if you do not have experience with it. Keep in mind that this is also the stuff used in assembling galvanized pipe (or simply 'galvanized'). PVC requires different instructions, and galvanized pipe has been around much longer. The manufactures it seems, are pretty lazy in that they always give the directions for galvanized but rarely for PVC. I have run into many tradesmen and old timers that also assemble PVC like galvanized. If your helper insists on three wraps of tape and then a good wrenching until all of the threads are no longer visible...take his beer away and send him home. Over tightening is the leading cause of broken parts, not only during assembly but also down the road. Both galvanized and PVC have tapered threads but PVC is still plastic and has its limitations. Instead of three wraps, give it 7-10 tight wraps and then compress them by "screwing" the part into a clenched hand. When joining the two parts, tighten them hand tight (as tight as you can possibly get them by hand) and then with a wrench give them an additional 1 1/2 to 2 turns. More won't cause the end of the world, just resist the urge to wrench it down to the bottom of the threads.

If you feel you may need to dissassemble your work in the future, you can use compression fittings, unions, and threaded fittings. For frequent dissassembly, you should use unions but they are the most costly option (though well worth it).

The LifeGuard silicone grease can be had for around a buck from your local swimming pool store (if you live in the South). Any brand will do the trick and can be found in your Home Depots pool section and/or plumbing isle. Vaseline, etc. can do funky things to black rubber products however many newer synthetic rubbers are unaffected by petroleum greases; they can make a mess of your tanks rather quickly though.

zennzzo
07-15-2006, 10:16 AM
I hear ya there...Just trying to help out BTW...when the original question is what it is, I was trying not to get too awfully technical...
PVC "purple primer" and "cement"
a bit of Silicone grease for the o-rings,
Teflon thread tape,
gorilla snot,
and ya can't forget the goop'n-slop'n :D

CHOMPERS
07-16-2006, 6:34 AM
I hear ya there...Just trying to help out BTW...when the original question is what it is, I was trying not to get too awfully technical...
PVC "purple primer" and "cement"
a bit of Silicone grease for the o-rings,
Teflon thread tape,
gorilla snot,
and ya can't forget the goop'n-slop'n :D


:ROFL: