ultra flex PVC and gluing...to prime or not to prime?

[Devaji108]

Ok this is todays Question:

to prime or not to prime the black ultra flex PVC to a 90?
this is for my return line coming over the back of the tank.

I am a bit confused here as some say to prime it with the blue primmer and other say not needed...

help clear up this confusion guys. after a week off from the build do to company i am eager to fish this up. :)

[ghatter]

I doubt it's really needed but I primed mine just to be sure. I already had the primer and it's not like it's a lot of extra work.

[ca1ore]

I didn't prime any of mine, though I did use the gorilla glue solvent that claims to be 2 in 1.

[Devaji108]

ok i"ll guess I 'll prime it and see...

[KingTriton1]

I really have no idea, but did find this

http://www.familyhandyman.com/plumbing/how-to-glue-and-join-pvc-plastic-pipe/view-all

Use the proper solvent for each type of plastic

" You don't need a primer with black ABS pipe. Read the label to match the solvent cement to the type of pipe you're using. "

[Devaji108]

thanks for the link King,
yeah I knew you did not need it with black ABS and I did not use it for my overflow. but was not sure with the ultra flex PVC stuff.

well i went ahead and primed it and cemented it seamed to work let it cure for 15hrs going a fresh water test now everything seams OK.

[ericarenee]

I actually just ran some of this last week..

I Prime and glue all of the joints ...

[ReefRescue]

The priming is to clean and remove all oils and then to soften the surface of the PVC joint so when the solvent is applied it bonds the two softened pvc surfaces.
For a real sure-proof PVC bond it is necessary to use a primer even though there are a ton of products in the market that claim that they do both. similar to car wash and wax products.
ABS is a less dense plastic hence why it melts easier even with just the solvent.
for a good pvc joint its definitely needed specially with flex pvc.

[Bent]

I've read in multiple handy man magazines that priming flex PVC will soften the material and lead to leaks.

But I have no actual first hand knowledge to share other than that.

[sleepydoc]

Oatey makes a Flexible PVC cement (http://www.oatey.com/products/plastic-pipe-cements-and-primers/oatey-pvc-cements/pvc-flexible-clear-cement) that's thicker and supposedly formulated to withstand vibration better than standard PVC cement. It can be used on regular PVC pipe as well, so you don't necessarily need two types of cement.

I've seen sites advising 'standard' cementing techniques - i.e. priming, applying the cement and twisting ¼ turn as you insert the pipe, as well as sites that recommend avoiding primer and not twisting the pipe.

FWIW, both Oatey as well as FlexiblePVC.net (http://www.flexiblepvc.net/Glues_and_Primers_for_PVC_Pipe-a/245.htm) both recommend using a primer.

Also on tangentially related note (but not part of the original question) - I have read that you should *not* use Krylon Fusion paint on flexible PVC as it softens the surface. I have no personal experience on this, however.

[DasCamel]

I've read in multiple handy man magazines that priming flex PVC will soften the material and lead to leaks.

But I have no actual first hand knowledge to share other than that.

Well, I did this a year ago for my return pump. Primed and used solvent on the flex PVC. Still extremely strong without leaks.

[sleepydoc]

yup - there are plenty of other threads around RC debating the necessity of priming. From the reading I've done, priming is generally recommended by the manufacturers and makes for a stronger joint. Because our applications are generally quite low pressure, the strength of an unprimed joint is plenty adequate and there are plenty of people who assemble their plumbing without primer and never have an issue.

[mmn]

yup - there are plenty of other threads around RC debating the necessity of priming. From the reading I've done, priming is generally recommended by the manufacturers and makes for a stronger joint. Because our applications are generally quite low pressure, the strength of an unprimed joint is plenty adequate and there are plenty of people who assemble their plumbing without primer and never have an issue.

I did. 1.5" PVC and no primer. So far so good (KOW)!

[Harry_Y]

I prime and glue everything

I also use the clear primer so it looks nicer

[Sonicboom]

Definitely clear primer if you are going to primer, nothing looks worse than purple drip all over nice white pipes. I always use teflon pipe thread tape, about 7 turns and it seals perfectly, then if I am happy with how everything is i might glue it. I just redid some plumbing to replace some ultra flex PVC with rigid PVC and noticed it still had pipe thread tape on it two years later...lol

[sleepydoc]

teflon tape on slip fittings??? No way I can recommend that, except for test-fitting. All it takes is one fitting to work its way loose and you've got 50 gallons of water on the floor, thousands of dollars worth of damage, and potentially a dead tank & burned out pump.

The only slip fittings that you can leave un-glued are the ones you don't mind coming loose.

[Sonicboom]

I didn't recommend it, just stated this is something I did and do. It was recommended by a plumber and I have never had a pipe come loose in almost 3 years. I actually taped up an elbow onto a pipe and gave it to a grown man to try and pull apart. Pulling straight out it was impossible to separate the two pieces.

[DrawnToBeaches]

I don't prime. I plumb in the industrial sector, and although we rarely use pvc the primer is just a scam for chemical manufacturers. I was using primer for a while but it really isn't necessary and unless you have the clear type or use pure acetone it's ugly as hell.

Edit: sorry for reviving this. At least the info is out for the next to ask

[DrawnToBeaches]

Edit old thread

[Ruckus16]

I don't prime at work or home

[Jone]

clear primer,,always use primer,,,put the glue on and DO NOT twist the pipe after you push together and make the connection,,hold tight for a couple of minutes and your done..

[DrawnToBeaches]

clear primer,,always use primer,,,put the glue on and DO NOT twist the pipe after you push together and make the connection,,hold tight for a couple of minutes and your done..
I'm curious why "always use primer"?

[sleepydoc]

PVC pipe cement is a solvent that dissolves or melts PVC combined with dissolved PVC solids. Prime is generally the same solvent without the dissolved solids. Priming the joint first softens the surface of the PVC and allows better penetration of the cement for a stronger joint. I've read claims that purple primer is colored purple simply to allow verification that it was used when work is inspected. I can't verify that, but I know of no other difference between the purple and clear primers.

I'll let you read the discussion above regarding primer for flex PVC...

There are many people on RC and elsewhere who have cemented joints without primer and never had an issue. You should note that plumbing for a fish tank is a very low pressure application, so a less-than-maximum strength joint is probably still plenty strong enough.