Flex PVC question

[muttley000]

Ok, so I am the worlds slowest plumber. I have to dry fit each piece and mark it before I glue it. With the flex PVC it is sticky feeling and I can not get it to slide into the fittings all the way. I tried sanding a small chamfer on the end to make sure I don't have a burr. I end up trimming things a couple times to get them the way I want them so I am nervous skipping my dry fitting step. Any advice?

[Ricks@reef]

That is the way it is supposed to work. PVC joints are called "interferrence fit" which means they are tight when dry so there is no excess space that has to be filled with cement when they are assembled. You will have to estimate the added length used when they slide all the way in when glued. Just take your time and plan out your runs. Good luck

[Aquatron]

Use primer on the fitting only no primer on FLEX pipe then install glue on fitting and push FLEX all the way into fitting and hold for 20-30 seconds. When you push FLEX into fitting it traps air if you don't hold it in it will push back out some....you don't want that. When you dry fit most fittings are 1 1/8" inset leaving 1/8" fluctuation so you can just add " between distance plus 1 or 2 x 1 1/8".

[ca1ore]

Ok, so I am the worlds slowest plumber. I have to dry fit each piece and mark it before I glue it. With the flex PVC it is sticky feeling and I can not get it to slide into the fittings all the way.

I used flex PVC on my last build and found the same thing. I practiced a few of my favorite OCD avoidance breathing exercises and just glued and shoved ..... And it all worked out OK. Nice thing about the flex stuff is that it is quite forgiving of slightly less than perfect precision.

[uncleof6]

Primer is unnecessary for spa-flex, just as it is unnecessary for pvc hard pipe... ...primer is not recommended for flex, (noted above) and it is not needed for new pipe, e.g. the fittings in this case, nor required for hard pipe/fittings under 4" in diameter....you do want to use a medium bodied cement however with spa flex.

[muttley000]

Thanks guys for the advice especially from some of the DIY forum people I respect the most! I will measure carefully and have at it. I am using the blue Oatey's rain-r-shine. I have read all sides of the primer debate, one thing I am not clear on is if cleaner should still be used or not. Lastly, I found that dipping the end of the flex in water allowed them to assemble further (still not all the way) do you think this hurts anything? I probably won't get time to start glueing till Saturday so it will be a few days before I can let you know how I came out.

[LelandF.]

Im a master plumber, and I had to go to a PVC gluing certification through my union, at Oatey's facility. Primer is ALWAYS needed. It is what makes the bond between the pipe and fitting. You need to prime the heck out of both the fitting and the pipe, spa-flex is no different. The glue fills the gap between the pipe and fitting. Always apply glue to both the fitting and pipe as well, and hold them together until set, so they don't push out of the fitting. Well primed PVC will push out of the fitting easily initially, so keep an eye on it for the first 10-20 seconds.

Leland

[LelandF.]

Sorry, didn't mean to have the imogi thumb, must've hit it on accident. Lol

[NTP66]

If you submerge the ends of the Spa-Flex in near-boiling water for a minute or two, it becomes pliable enough to make working with it significantly easier.

[A sea K]

Im a master plumber, and I had to go to a PVC gluing certification through my union, at Oatey's facility. Primer is ALWAYS needed. It is what makes the bond between the pipe and fitting. You need to prime the heck out of both the fitting and the pipe, spa-flex is no different. The glue fills the gap between the pipe and fitting. Always apply glue to both the fitting and pipe as well, and hold them together until set, so they don't push out of the fitting. Well primed PVC will push out of the fitting easily initially, so keep an eye on it for the first 10-20 seconds.

Leland


One thing I would like to note about this. A lot of our sch 40 bulkheads are made of ABS. When using any ABS do NOT use primer on the ABS.

[LelandF.]

You still need to use primer on ABS. The glue is different though. You'll need an all purpose glue that says it's for PVC and ABS. I haven't seen many ABS fittings. Most ABS fittings are black. The white, clear, or gray fittings are all PVC. ABS is not used anymore in my area of the US, but it's still very popular in other areas, such as the east coast, and North east in New York, and Boston.

Leland

[A sea K]

Well I'm certainly no master plumber. What I do know is the can of Oatey All Purpose Cement clearly states on the label to NOT use primer on ABS pipe or fittings and that the sch 40 bulkheads I use (aquired from a popular retailer and RC sponsor) are ABS and not PVC. Probably does'nt make a hill of beans difference anyway.
Just wanted to let people know is all

[uncleof6]

Thanks guys for the advice especially from some of the DIY forum people I respect the most! I will measure carefully and have at it. I am using the blue Oatey's rain-r-shine. I have read all sides of the primer debate, one thing I am not clear on is if cleaner should still be used or not. Lastly, I found that dipping the end of the flex in water allowed them to assemble further (still not all the way) do you think this hurts anything? I probably won't get time to start glueing till Saturday so it will be a few days before I can let you know how I came out.

In reality, you only need the cleaner if the pipe is dirty... I don't mean dusty, simple wipe will take that off, I mean if the pipe has grease or other heavy "dirt" on it. 99% of those in the reef hobby are using new off the shelf pipe, they are not digging it up from underground where it has been for several years, and repairing leaks caused by production driven plumbers, who were in too much of a hurry to make good solvent welds.

[uncleof6]

Well I'm certainly no master plumber. What I do know is the can of Oatey All Purpose Cement clearly states on the label to NOT use primer on ABS pipe or fittings and that the sch 40 bulkheads I use (aquired from a popular retailer and RC sponsor) are ABS and not PVC. Probably does'nt make a hill of beans difference anyway.
Just wanted to let people know is all

On your behalf: From the label of a can of Weldon 773 ABS cement:

1) Cut and deburr or bevel pipe 10 - 15° Clean and dry joining surfaces (note: nothing about chemical cleaner)
2) Check dry fit (edited remaining about interference fit)
3) Use a suitable applicator at least 1/2 the size of the pipe diameter
4) Apply cement inside fitting, avoid excess cement inside (e.g. you don't glob this stuff on) apply cement to outside of pipe equal to the socket depth
5) On bell end pipe, do not coat beyond socket depth; or allow cement to to run beyond bell. (E.G. don't glob it on)
6) Assemble while cement is wet; If not wet, recoat parts before assembly; Twist 1/8 - 14 trun until reaching pipe stop (point the pipe stops moving into the fitting) To avoid pushout, hold for 30 seconds. Wipe off excess.
7) Allow 3 mins for good holding strength and 30 minutes up to 4" at 60°F and above... for pipe sizes over 4" or temps below 60°F allow longer cure time.

So what is the point here, and how is this supporting your assertion? A "Master Plumber" says you must use primer on ABS. The label instruction" for ABS cement say nothing about having to use primer...Between these label instructions, and the label on the can of Otay All Purpose Cement, I think what is right, can be decided using common sense...

[shermanator]

Im a master plumber, and I had to go to a PVC gluing certification through my union, at Oatey's facility. Primer is ALWAYS needed. It is what makes the bond between the pipe and fitting. You need to prime the heck out of both the fitting and the pipe, spa-flex is no different. The glue fills the gap between the pipe and fitting. Always apply glue to both the fitting and pipe as well, and hold them together until set, so they don't push out of the fitting. Well primed PVC will push out of the fitting easily initially, so keep an eye on it for the first 10-20 seconds.

Leland

I'm an amateur plumber (at best), but when I have used primer (+ Oatey Rain N Shine glue) on FlexPVC to PVC fittings, I can always pull the joint apart (and I'm not all that strong). When I skip the primer, and just use glue, the joint holds up to whatever force I can muster (and they have not leaked). Maybe I'm doing something wrong?

[uncleof6]

The instructions on cans of Otay pvc cement are very similar to the label instructions posted in the preceeding post. The major difference being that the PVC cement label does mention primer. (I don't have a can handy to quote exactly, and I am not going to HD to get any to quote what anyone can read for themselves :) )

'Use primer IF required.' (emphasis added) The instructions do not say or imply that it IS required, or anything remotely indicating it is a necessary part of the process. Aside from pvc pipe 4" in diameter and larger, the only "times" I have seen the requirement for primer and pvc pipe have been in the Job Specifications, i.e. the engineer has specified that primer is to be used on all pvc joins....it is a part of the contract. The codes can vary from jurisdiction to jurisdiction, and only applies within the specific jurisdiction for which the codes are written and apply no where else.

Primer is a personal choice. It hurts nothing, other than the wallet, but it adds very little to the join. In simple terms, if you can't make a good solvent weld without the primer, you can't make a good solvent weld with the primer. It is in the technique...I have been to these "pvc gluing classes" myself, and the company reps come up empty handed when challanged on the primer....

[uncleof6]

I'm an amateur plumber (at best), but when I have used primer (+ Oatey Rain N Shine glue) on FlexPVC to PVC fittings, I can always pull the joint apart (and I'm not all that strong). When I skip the primer, and just use glue, the joint holds up to whatever force I can muster (and they have not leaked). Maybe I'm doing something wrong?


Don't use primer with spa flex. First spa flex (FlexPVC) is already very soft, and primer simply turns it into a gooey mess. I sent a text yesterday to one of my subs, "Primer with spa-flex?"; the response "*expletive* no...." You have not missed a thing, you simply learned the hard way. :)

[A sea K]

The only point I'm trying to bring to this discussion is simply that if it is advised against using primer with "ABS" pipe and fittings from one of the major manufactures of PVC/ABS cement then I'm pretty sure there could be a potential problem if you do.
Given that most of the bulkheads we use are of ABS, and if it would present a problem later down the road, the bulkhead area in most systems is one of the hardest areas to repair on a functioning tank, at least in my experience.
It was only a word of caution, proceed as you wish.

[uncleof6]

Im a master plumber, and I had to go to a PVC gluing certification through my union, at Oatey's facility. Primer is ALWAYS needed. It is what makes the bond between the pipe and fitting. You need to prime the heck out of both the fitting and the pipe, spa-flex is no different. The glue fills the gap between the pipe and fitting. Always apply glue to both the fitting and pipe as well, and hold them together until set, so they don't push out of the fitting. Well primed PVC will push out of the fitting easily initially, so keep an eye on it for the first 10-20 seconds.

Leland

First, you have the facts wrong. The primer is a surface preperation, it does not "make the bond between the pipe and fitting. The solvent cement melts the two pieces, and the melt co-mingles, and solidifies as the SOLVENT evaporates. PVC cements have melted PVC in them that acts as filler, when needed. Because spa flex has an irregular surface (unlike hard pipe) the filler can be helpful. I am not sure what class you went to, but you did not go to the same class I went too... (I am a General and C10, Merit Shop) I have so called "Master" plumbers that worked for me from time to time, (sub-contracted) always had a good laugh over the ruckus raised over primer on new pipe, most said why? Notwithstanding the codes...

Second, and this may be a touchy subject, but PVC cement is not glue. The process of joining PVC fittings and pipe is not "gluing." The process is called solvent welding, and the substance used to initiate the process is a solvent, (not glue, not primer) with dissolved (melted) PVC in it. It is an evaporative process in which the solvent evaporates, leaving behind a "weld" or simply put, melts the two pieces together.

In the electrical field, there are lamps and there are bulbs. On the first day of your apprenticeship, they tell you "never ask for a bulb unless you want a bulb." E.G. if you ask for a "bulb" for a fluorescent fixture, that is exactly what some "smart ***" journeyman will bring you: an Incandescent Light Bulb. Well they don't work in fluorescent fixtures and you look/fell very silly...if you ask for a fluorescent lamp, or simply a lamp for this fixture, you will get the right part. Layman are not expected to really get this, though I mention it from time to time just for grins, however for a pro in his field, it should be second nature...

[uncleof6]

The only point I'm trying to bring to this discussion is simply that if it is advised against using primer with "ABS" pipe and fittings from one of the major manufactures of PVC/ABS cement then I'm pretty sure there could be a potential problem if you do.
Given that most of the bulkheads we use are of ABS, and if it would present a problem later down the road, the bulkhead area in most systems is one of the hardest areas to repair on a functioning tank, at least in my experience.
It was only a word of caution, proceed as you wish.

I am not opposing your assertion I am reinforcing it: with another example of the inaccuracy of the statement "you still need to use primer on ABS" :)

[Rock Dowg]

Just wanted to put in my 2 cents worth.

I have been a plumber for almost 20 years and wanted to share my perspective on this subject, this comes from years of trial and error,

Where I live we use ABS and PVC pipe equally. and I can tell you that I have never used primer on ABS, in fact I have never heard of anyone using it on ABS until I read this post.

ABS and PVC, Without getting technical, are two different blends of plastics that make them different in nature. ABS is softer and PVC is harder (and brittle). the glues for each kind of pipe work differently to bond or glue the pipe and fitting because there 2 different kinds of plastic, its like gluing two pieces of wood together vs two pieces of metal, you wouldn't use the same glue for both


primer has basically 2 functions, to clean the pipe and also to soften it so the glues/solvents bond better.

If your pipe is new then it may not need to be cleaned, however, you can't always see grease and oils on the pipe, particularly oils from your hands. ABS is much more forgiving when it comes to how clean the pipe is but PVC is not and the solvents may not stick if the pipe isn't clean. The primer ensures that the pipe is clean.

As for softening the pipe for the solvents to bond. ABS by nature is already soft and does not need to be softened with a primer, in fact it would just make a mess. PVC on the other hand is hard and by using a primer it will soften and to some degree melt the pipe so the the solvents/glue will bond better.

Some glues have some primer mixed in so primer is not necessarily needed.

Do you need primer? not really, in a fish tank system your not dealing with very much pressure so you can do it without primer,however, in my experience over the years I would always use primer on PVC to ensure a strong joint and because your chances for a leak is greater if you don't. and no one likes a leak!

Spa tubing is PVC but has plasticizers added to it to make it softer and more flexible. Using primer will soften it too much and will make for a weaker joint that is more likely to fail over time. I would recommend priming the fitting but not the spa tubing.

when gluing PVC to ABS (like ABS bulkheads) look for a Multipurpose glue or Transition glue that is for this purpose, then read the instructions on the can for how to use it

Here's a tip: most primers are purple because inspectors want to see the color so they know that the joint was primed ( Its code where I live and work, but some places its not) working with purple primer its hard sometimes to make it look good because the primer gets all over everything. They do make a clear primer that makes it much easier to keep things clean. A local plumbing supply store might have some or they can get it for you.

[muttley000]

Just to close the loop on this, I was careful measuring and glued 1 end and let it cure a day. I then only had to nail one end per length of flex. They all came out fine, thanks for the advice! For the record I used Oatey's rain r shine with no primer. The last of the joints that I did on Sunday are rock solid, can't twist them or anything like that. I suspect that I wouldn't have had leaks without glue as tight as the flex was, although I don't think the joints would have assembled without the lubrication of the solvent! It will be weeks before I do an actual water test, but I will let you know it came out well!