View Full Version : Proper Gluing Techniques for PVC

Norm Walsh
10-13-2010, 01:30 PM
The question of proper gluing techniques for PVC was recently brought up in another thread, so as not to highjack that thread, I've started a new one.

A good solvent weld begins with a properly cut pipe, doesn't really matter how you achieve the cut, could be by a ratchet style cutter, hand saw, chop saw, whatever, the important thing is that the end of the pipe is cut as squarely as possible. This will help provide the maximum bonding area inside the fitting.

After cutting the pipe, "deburring" is the next step. This means removing all the loose pieces of PVC left from the cut. I usually use a razor knife to do this but sandpaper will work or an actual "deburring" tool is available.

Next is "beveling", it's recommended that the end of the pipe be beveled 10*-15* to help entry into the fitting. Additionally this will help the glue from being wiped of as the pipe is being inserted into the fitting.

Test fitting the joint "dry" (without glue) is a good idea as well, your pipe should enter approximately 1/3 to 2/3rds of the depth of the fitting easily.

The last things before gluing are to make sure the pipe and fittings are clean and dry. Moisture can effect joint performance, there are "wet-R-dry" glues available for cases were you can't be assured the pipe is dry and they should be used in those cases. Secondly, the "duaber" or applicator, should be properly sized. It should be approximately 1/2 the size of the pipe your gluing in order to get sufficient coverage. Personally, I use a 1" dauber for everything. It's perfect for 1-1/2" and 2", a little small for 3" and 4" (sometimes I'll have to double dip) in the cement, and a little messy for the small stuff.

On to gluing.

Using the proper glue is essential. My local supply house carries the IPS/Weld-On brand so I will refer to it. I use the "P-70" primer which is their premium level primer and is also good in cold weather situations. For glue, I use the "705", it's a high strength cement that is good for Sch.40 pipe up to 6" and has a fast set time. For a slower set time in hotter weather I would recommend the "711". When using flexible PVC I use "795" which is also fast set but forms a more flexible joint. When joining PVC & ABS I use the "794" which is a transition glue. For any of these glues if you see the number 2 in front (ie....2705, 2711,2794....etc.) it's older stock, IPS went through a label change a year or so ago.

Most building codes require the use of purple primers as an indicator that they where used, though it's true that cement alone can create an adequate joint. I highly recommend using a primer, whether it's purple, or my preference, clear. Possibly contrary to popular believe, primer is not for cleaning, it will clean, but it's primary purpose is to soften the plastic in order for the cement to fuss together the joint easier.

To begin gluing the pipe together start by applying primer to the fitting socket, don't be shy, you want to work the primer in and soften the surface but don't allow the primer to puddle.. Next, apply primer to the pipe, once again be aggressive in the application, but only for the depth of the socket on the fitting. As a "rule of thumb" when applying the primer, you want to wipe it on hard enough to remove the printed label on the pipe.

After priming the pipe, hit the fitting socket one more time. With the primer still wet apply a thick even layer of glue on the pipe, once again, enough to cover the entire depth of the fitting socket. Next, apply a thin layer to the fitting socket, covering the entire socket.

Now go back and apply a second coat of glue to the pipe before you put them together. With the glue still wet, assemble the joint, giving it a 1/4 twist while you insert the pipe. When you reach the bottom of the socket stop turning. Hold the joint together for at least 30 seconds to avoid any "push out".

After making sure the joint has an initial set, wipe off any excess glue around the joint. This not only make the joint look nicer it allows the solvents to more easily evaporate from the joint.

One last thing, make sure your glue is fresh, if it has turned to "jelly" or is otherwise lumpy throw it out.

10-13-2010, 01:37 PM
A really good tutorial Norm, and badly needed for many folks here!! Thanks and good job! Maybe this should be a sticky.

10-13-2010, 02:00 PM
Thank you Norm!! I think this is needed info. Thanks for catching my hint in the other thread.

Mods: I think this needs to be a sticky.

This may come as common sense to most but if your new to plumbing, it may not come naturally.

From Experience, sand or dirt on your joint is bad. Anything but a dry joint is bad. Don't try to use solvent sparingly. If your solvent is turning milky, throw it out. Be extra careful when gluing to a valve not to get glue or primer on the ball or gate.

A technique my father taught me (right or wrong) when I was a teen as he threw me in the hole to do the dirty work.... If the position of the pipe in the fitting isn't critical, he had me lightly twist the two pieces, while pushing together until I couldn't physically twist them anymore. He came from a long line of pipe fitters and to this point I have never had a solvent welded joint fail me however, to this day I can't sweat a copper fitting to save my life.


Norm Walsh
10-13-2010, 02:31 PM
Good tips as well Jerry, when in the trenches it's easy to get dirt in the joint. If your in the middle of a joint and you get a bunch of dirt in the glue, stop, wipe off the dirt and start over.

There are two parts to a solvent joint, the part deep in the socket is the "fused" area (about 1/2 the depth), the other is the "bonded" area, this is the area that needs to be filled with a sufficiant amount of glue. Once the joint has been made and "fusion" has started, overtwisting the pipe can weaken the joint. Maybe Dad wanted to see you sweat :D:

Hi Utsuri
10-13-2010, 02:46 PM
Great post, Norm!

In my experience, just lightly sanding the rim of the pipe will be enough to have the pipe slide easily into a fitting.

Another trick to getting nice clean looking joints is to apply the glue to only 1/2 the depth the pipe will fit into the fitting. So... if a section of pipe will go one inch into a fitting, only apply glue to the first 1/2 inch of the pipe. As you slide the pipe into the fitting, the glue will be spread out along the entire length of the connection. Below is a picture of the results I got using this technique. I have had "zero" leaks so far. :D:



10-18-2010, 11:26 PM
Great tutorial. A couple of things to add... The larger cans of cement or primer means it has a larger dauber. The 32 ounce cans have the best dauber size for three and four inch pipe, but they are too large for smaller pipe. 16 ounce cans of cement or primer have a great dauber for 2". And the 8 ounce cans have a dauber that works great for pipe under 2".

There is a cleaner compound that you can find on the shelves as well. It is based to remove the oils but acetone works just the same.

As Norm mentioned, none of us ponders should be using the purple colored primer. It is colored purple for inspections. Ponds are not inspected, so the clear primer makes your installs a lot cleaner looking.

To reiterate what Norm said, push out is the most common failure of PVC joints. Hold the joint together for 30 seconds!

10-19-2010, 11:43 AM
To make your joints cleaner us acetone as a primer. It does a great job and is a lot cheaper than the other primers.

11-23-2010, 05:26 PM
cleaner and/or primer. i use it every time i need to glue something with exception of PVC to ABS. that is a no no. and will use a transition glue.

a generally pick up a can of cleaner / primer the same size as the can of glue i am getting. and when the glue gets bad or i run out. i toss both cans out at the same time.

Why is that? the cleaner / primer will start getting stuff in it and by the time you use up a can of glue. the cleaner / primer has to much gunk in it, and does not soften the pvc pipe as good as it should!

11-23-2010, 05:28 PM
that 1/4 twist as you are putting things together.

2" and smaller can normally be done with a single person.

but when ya get to 3" and more so 4" pipe work. it tends to be very help full to have someone else around. say one doing priming / cleaner and then applying the glue. while the other person holds the pipe / fitting. and then puts them together when needed. and or you might need to people just to twist and push things together. those 30 plus seconds after initially getting the pipe and fitting together can be rather awkward if almost impossible for one person at times. and a second person can help out alot!

11-23-2010, 05:32 PM
i know folks like things to look neat. but looking neat vs wanting to make sure you have something glued. i will put a little extra primer / cleaner that is purple or some other color than pipe i am working on. to make sure i know i glued that area together. and if ya don't like the look of the color of primer on your pipes then spray paint the pipe work after wards, some folks go all out in different colors others just paints everything one color so it blends in.

i rather be safe than sorry. trust me, it is no fun trying to fix a leak, were you can't even squeeze your hand down near the pipe to just look at it let alone try to glue or cut the area out to replace it.

also, don't get in a rush and try to do multi pipes and fittings at one time. *BIG NO NO* primer / cleaner dries or the glue dries to much and you end up with a leak. one fitting one pipe at a time!
and if you will need to be moving a fitting this way and that way to get the next pipe or fitting on. allow the previous fitting to initially cure. ((read fine print on the glue for inital cure time)) or you may risk bang things apart as you put the next pipe / fitting together. not trying to scare ya, but more of trying to get them folks that get in a rush to slow down and take there time.

11-23-2010, 05:53 PM
beveling, or rather make that, ya kinda make the outside end of the pipe coned shape. it doesn't need to be much but boy can it make a difference more so when ya get into a tight area. and you end up fighting the pipe and fitting together, and sometimes end up fighting things enough that the glue dries to much on you *sad face* beveling the end can make life easier, granted extra work. but can save you.

be carefull when dry fitting as well. don't try and jam the pipe down into a fitting as far as it will go. when ya go to glue and put fitting to pipe together yes, but not when dry fitting. if you put deep scrapes on the inside of the fitting or on the outside of the pipe. you can risk a possible leak. later down the road.

just remember though once you glue and put things together the pipe will slide further into the fitting, vs dry fitting, and make sure when you are cutting lengths of pipe and dry fitting things you keep this in mind.

11-23-2010, 09:15 PM
After reading Ryan's posts another thought occurred to me I learned a while back. If you go to Lowe's and HD you will see SCH 40 pipe, but the 90s, 45s, WYEs, connectors and such are drain waste and not pressure rated (ie SCH 40). This is fine for pond use as there is not much pressure, but when you bury pipe you should try to use the SCH40 fittings. Lowe's carries SCH40 fittings up to 2", HD carries none. Next time you are in Lowe's grab a standard drain waste 2" connector, than find the section that has the SCH 40 pressure connector in 2". The SCH40 connector will be twice as long giving twice as much glue surface. Really useful when burying long runs.

11-24-2010, 12:51 PM
i am a tad against using rubber fittings with pipe clamps on pressurized lines after the pump. and will suggest folks using "unions" between filters and the plumbing. this is due to rubber fittings can bulg and crack possibly.

but for gravity flow pipe runs and the filters that hook up to them. i will suggest using "rubber fittings with pipe clamps" one on each inlet/outlet/waste line on the filter. rubber fittings allow for a little extra wiggle room, and makes attaching filters to plumbing easier. and when you are trying to hassle around a 3" or 4" pipe to a filter. and trying to get the pipe to bend to your wants (which is a no no) you could inadvertently cause a leak to happen later down the road. by forcing a pipe / fitting to bend to much.

air lines = unions. risk for to much pressure.

i don't recommend using rubber fittings every were you can, but only as needed when needed. and only in a spot were you can access them and check on them. such as in a filter pit. beyond using them to make the initial hook up to say a gravity flow filter. i tend to think of rubber fittings as "repair" fittings. not initial plumbing fittings when ya put everything together.

11-24-2010, 01:31 PM
Love Hi Utsuri plumbing is compact and done cleanly. and he used "short sweeping 90's" on nearly everything he could.

but it looks like he ran into a problem, either cut a pipe short or didn't have enough room for a "short sweeping 90" and ended up using a "coupler" and a "sharp 90"

Sharp 90 = is a BIG NO NO in gravity flow filteration, more so on pipe runs between bottom drains and the first filters that the pipe runs connect to.

A sharp 90 = a clogger were leaves, twigs, muck can build up. a Short sweeping 90 or a more preferred long sweeping 90, are more ideal for gravity flow of water.

after you get past the inital first filter which is normally some sort of combo "pre filter and Mechanical filter" you can get away short sweeping 90's and if needed a "sharp 90" but generally staying away from "sharp 90" as much as possible. for example like Hi Utsuri, only using one to deal with that one spot.

local hardware stores (lowes, menards, homedepot, acehardware, etc...) most likely do not carry "long sweeping 90's, or even short sweeping 90's" for pipe sizes you will need. this is very common, and folks generally need to get phone book out and look up local "wholesale supply stores" in there area to find a place that sells the sweeping 90s.

or do as i did, knowing no place near me sales any good ball valves or knife valves in 3" and 4" i just ordered everything over internet and picked up approx amount of long sweeping 90s i needed at same time i got valves ((to save on shipping)) and then for 1 to 4 90's i didn't have suffered with what local hardware stores had. and if it came down to it. i would use 2 "45's" to make a short sweeping 90.

there is one thing, if you are required for an inspector to come out to check plumbing, they may not allow certain things. and it has came up as an issue for some folks. hasn't for me, so i don't remember the details about reason for the 90's and being an issue.

01-14-2011, 03:00 AM
Interesting, thanks for sharing.

Norm Walsh
01-14-2011, 11:33 AM
To make your joints cleaner us acetone as a primer. It does a great job and is a lot cheaper than the other primers.

You might go through a quart of primer during an average build. The difference in primer vs. acetone is about $4.00. Heck.....go without that second Starbucks on the first day of the build and you've paid for the primer :cool3:. Use the proper tool/product for the job. ;)

After reading Ryan's posts another thought occurred to me I learned a while back. If you go to Lowe's and HD you will see SCH 40 pipe, but the 90s, 45s, WYEs, connectors and such are drain waste and not pressure rated (ie SCH 40). This is fine for pond use as there is not much pressure, but when you bury pipe you should try to use the SCH40 fittings. Lowe's carries SCH40 fittings up to 2", HD carries none. Next time you are in Lowe's grab a standard drain waste 2" connector, than find the section that has the SCH 40 pressure connector in 2". The SCH40 connector will be twice as long giving twice as much glue surface. Really useful when burying long runs.

Clarification.....As I call them "hard 90's" and "DWV 90's are both SCH40. The difference as you pointed out is the pressure rating. This relates back to the hub depth, pressure rated fittings have a deeper hud depth.


I do stock "pressere rated long sweeps" http://www.bwkoi.com/PVC-Fittings-Plumbing-Parts-sc-152.html

11-08-2011, 09:18 PM
Wow really good info and I've had my share of learning by the school of hard knocks on what works and what does not work tweaking my recirculating systems. One question I have is the following: How long after gluing can you run water through a PVC pipe? It's not on any of the cans of glue I've seen. Seems to me I've seen plumbers run water not long after gluing but is it better to wait if you have time?