primer on pvc. is it necessary?

[fungia]

i know that pvc glue is 100% needed on pvc connections and teflon tape on all threads but do i need to use primer on the pvc?

 

[ScottC]

PVC primer actually "gums up" the PVC. When you prime the parts/pipe, run your fingernail over it and you'll see what I mean. Now when you add the glue, the fittings and pipe form a better bond since the two "gummy" surfaces now meet and cure together.

You're putting all this time and money into your system, so it makes sense to take every step available to insure a professional job.

 

[fungia]

that makes sense. thank you scott, you guys rock.

 

[ChrisRD]

The cost of fixing the leaks later will be a LOT more than the cost of the primer. :wink:

 

[Robin Goodfellow]

hi.
I have a few fittings that were done without primer, but I never suggest anybody doing anything the way I did.

 

[mountainbiker619]

first time I did the plumbing on my last tank I used primer. Some things I noticed was due to the thickness of the primer, was not able to insert the pvc all the way into the fittings. Another thing I noticed was due to the tight fit from bare pvc to bare pvc, most of the primer was being scraped off while inserting the pvc into the fitting. The second time I did the plumbing on this tank (was due to plumbing design change) I did not use any primer but went crazy with the glue to the point when I inserted the pvc into the fitting, the extra amount of glue formed a nice bead around the end of the fitting. My return plumbing system is a pretty high pressure system utilizing 3/4" pvc...been 6 months now with no problems.

 

[ChrisRD]

Some things I noticed was due to the thickness of the primer, was not able to insert the pvc all the way into the fittings.

Are you sure you used PVC primer? All the PVC primers I've ever used were water thin. The glues OTOH are much thicker (and available in several weights).

 

[mountainbiker619]

Some things I noticed was due to the thickness of the primer, was not able to insert the pvc all the way into the fittings.

Are you sure you used PVC primer? All the PVC primers I've ever used were water thin. The glues OTOH are much thicker (and available in several weights).

yeppers..100 percent sure.

 

[tazdevil]

That must've been bad primer. The purple stuff should be water thin as Chris mentioned. From a plumber I know- If you don't prime, plan on re-plumbing your system soon. (this was in regards to house plumbing, I can't imagine it would be any different to plumbing a SW tank, and consider pressures may be higher from pumps etc.)

 

[mountainbiker619]

like I mentioned above..I went crazy with the glue..I feel very confident in my system..if it springs a leak and I have to redo it..then so be it..its to late now..I will cross that bridge when and if it ever arrises.

 

[Anonymous]

It definitely had to be bad primer. Methylethylketone is thinner than water and evaporates inredibly fast (so fast that if you get any on your skin and it will feel like ice burn).

 

[Robin Goodfellow]

...evaporates inredibly fast (so fast that if you get any on your skin and it will feel like ice burn).

hi.
Actually, quit a bit of it will work its way thru you skin and get into the bloodstream on the way to your liver... this is why I don't work with VOs like I used to in the school days.

 

[Anonymous]

I never use primer on sprinkler systems or my tanks. I have never had any problems at all. I do make sure the PVC is clean, and use globs of glue. I make a 1/4 turn once the fitting is pushed on, and i'll add more glue around the outside seam if needed.

Louey

 

[Anonymous]

If using Cpvc you must prime.

If using PVC up to like 1.5 " you do not need to prime.

Bryan


BTW I actually think if the PVC is going to be used for pressure apps, you need to prime it. Plumbing a return pump is not a pressure app. Plumbing a system that will be pressurized needs to be primed

also, using primer is ugly looking if it is something that will be visible.

Bryan

 

[Saltykirk]

whether or not you prime is up to you. I do it because it cleans the two surfaces so you get clean contact all the way around the seal. I let the primer dry before I glue. Try putting the glue in the female end of the joint. Smear it all the way around the female coupling too. Insert the male end(no this isn't sex ed~), and twist. You should see a bead all the way around the outside. She'll never leak and make you a fine ship indeed cap'n! Oops, I left the lid off the glue again, lah lah lah lah lhalahlah ..........

 

[Anonymous]

"hi.
Actually, quit a bit of it will work its way thru you skin and get into the bloodstream on the way to your liver"

Yup, fun stuff.

 

[ChrisRD]

I do it because it cleans the two surfaces so you get clean contact all the way around the seal.

This is why I do it too. I figure it's cheap and easy to do and PVC manufacturers recommend you use it.

FWIW, the reason "purple primer" is purple is for inspection purposes - ie. so the engineer or building inspector can be sure the contractor primed the joints before gluing (so, obviously someone thinks it's important). :wink:

In truth, as mentioned above, in a low (or no) pressure application like aquarium plumbing it's not critical but I like to do it for the added assurance that I've got a good, properly constructed joint.

JMO

 

[ScottC]

I never use primer on sprinkler systems

Well, if that leaks it wont warp the walnut floors and carpet!

The primer is water thin and burns like he!! when applied to the skin or eyes, I was lucky enough to spill an entire can of the stuff down my shoe and thought my foot was going to burst into flames!

 

[Dan81]

you mustr have extremly sensitive skin, I spilled a whole can of the purple stuff on my hand and it felt cool and had a drying effect like acetone or rubbing alchol. I do vote yes on the usage of primer.

 

[ScottC]

it wasn't the purple stuff, it was the clear primer. And it was a quart of it!