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I'm cementing some schedule 40 PVC pipe using the best instructions I could find ( http://www.tchristy.net/pdf/ChristysTechManual_v5_English.pdf ). The outside of each joint looks fine, but inside there's often a mess of plastic scrapings, PVC primer and PVC cement:

PVC Pipe Cement inside junction at stop

PVC Sprinkler Pipe

The dross could clearly affect water flow or clog a filter. I won't use PVC pipe for drinking water because of lead (See http://chej.org/2013/09/pvc-pipes-bringing-toxic-lead-to-drinking-water/ ), but for those that do, the bits of plastic in the water could be an issue.

I've already tried rotating less while inserting, but that's not always practical. I'm cutting pipe with a ratcheting PVC cutter and deburring with sandpaper.

How can I get better looking interior joints?

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  • Did you deburr the pipe after cutting it? How did you cut the pipe?
    – Tester101
    May 15, 2014 at 20:27
  • Answers above. The cutter is a big box special: a miserable tool not worth the low price. The cuts are clean though not particularly square.
    – Bryce
    May 15, 2014 at 20:57
  • If you can get a miter saw to where you're working, that'd be good.
    – Edwin
    May 15, 2014 at 21:13
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    It appears the primer is overly softening the fitting plastic. Apply primer to the pipe first and use only enough of both primer and cement to fully cover the mating surfaces. Try to work quickly once the primer is applied.
    – bcworkz
    May 15, 2014 at 22:22
  • The purple primer/solvent instructions state they want a thick coat, no holidays, go over it twice. I'll try less solvent. Post primer I'm at 30 seconds before the joint is done.
    – Bryce
    May 15, 2014 at 23:50

6 Answers 6

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That level of glop is not normal.

Some things to check:

  1. Is the pipe end deburred? A file plus sandpaper to finish works well.
  2. Are the pipe & fittings dry? Water can do strange things to PVC cement.
  3. Be firm, but don't push too hard, and don't over rotate. 1/8 of a rotation is enough.
  4. Work quickly, but do let any residual drips in the primer evaporate before moving on to glue.
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  • Never having seen this I can only assume you were pushing WAY to hard and turning it caused a boring action in the softened plastic. Otherwise you fell victim to substandard fittings; a Home Depot specialty.
    – Mazura
    Dec 19, 2014 at 7:43
  • Yep, Home Depot.
    – Bryce
    Dec 23, 2014 at 2:21
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Make sure primer is wet when applying solvent, and be sure to bevel the pipe end. Not doing so is a classic mistake made by many professionals. The pipe end is scraping off the solvent and slopping it at the end because it's not beveled, and its wider than the inside of the fitting. Using too much solvent inside the fitting can somewhat cause this, but it's more likely that the primer is not wet when the solvent is applied, and couple that with an unbeveled pipe, you have yourself glopping at the end. So, bevel the end, and make sure the primer is wet when applying solvent. problem solved

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I think your largest problem is too-thick (old, perhaps?) cement... although I've never seen such a nasty glop inside any PVC (or CPVC) pipe joint of any size.

Nobody seems to have asked whether you ream, as well as deburr, your pipe before glueing... but I cannot think that failure to ream would cause a problem like this.

You're using real "PVC cement" from the store, and not something somebody whipped up in their basement, based upon acetone? Your buildup looks to my eye like the solvent in your batch is far too active, and is melting the pipe very aggressively. Could I get you to try another fresh can from the store?

I'm not sure what passes as "primer" where you are, but primer here is more a cleaning agent than anything else; the cement does all the work of bonding the pipe to the fitting. I saw, give it a quick swipe of primer, let the primer dry, apply cement, and immediately join pipe to fitting - straight insertion followed by about 1/4-turn. By the end of the 1/4-turn, the cement has always set up tight - and I barely have enough time to align (where alignment is necessary) my fitting with my Sharpie mark on the pipe. Peeking in through a coupling, all that can be seen is the reamed end of the pipe with a very small bead of cement around its rim.

You might find it handy to use a coarse-toothed hacksaw blade (in a hacksaw) to cut PVC pipe.

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  • The cement was brand new. Eventually with some practice I was able to make good joints. Early joints I think I rotated the pipe too much while it was all wet.
    – Bryce
    Aug 21, 2014 at 5:33
  • You MIGHT have been applying glue too early, too; it looks like there's a lot of still-sopping-wet primer inside that coupling. Primer isn't part of the chemistry that makes the joint, and too much may actually interfere with the cement. You ARE applying cement to both the pipe AND the fitting, correct? You don't need much more than enough to get it completely wet.
    – TDHofstetter
    Aug 21, 2014 at 5:54
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From what I can see it appears that there was a scrapping of the cpvc cement upon joining the pieces and twisting action like screwing in the pieces together. Gluing PVC pipe or abs pipe is the same and I have never added cement to both parts to be glued. The process I use is to add cement to the male piece and then push with a slight turn action. This ensures that the excess cement is pushed out of the fitting onto the pipe. Preparing the pipes to weld always precedes the welding of the materials with cleaner and primer for the strongest weld possible.

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What I have found is folks usually use two much glue especially on the female side. To eliminate the excessive problem you are having only lightly prime the fittings, with cleaned primed fittings ready only put the glue on the male part and do not coat the very end. Use a twisting action when assembling. This method will produce only slop on the outside of the fitting if two much glue is used. I have been using this method for many years and had very few problems with filters / regulators getting gunked up. Any excess on the female part ends up being pushed into the pipe as your photos show.

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This should never happen. No matter how much cleaner you use our how much glue... the best I can think is that either the glue and cleaner you used is not proper for off, or waaaaaaaay too much force was used in joining the pipe. Either way, this shouldn't happen.

To recap, in order to join pvc, clean both the pipe and fitting, allow any pooled cleaner to evaporate, or just tilt the pipe to allow it to run off, then apply a decent layer of glue. But one swab from the can should be enough glue for the pipe and fitting. Apply the glue to both pieces, then press together, turn, and hold firmly together for around 15-20 seconds. Once the joint is pressed together, you can wipe off effed glue from the outside, but the pipe shouldn't warp. If this continues, I would suggest a new can of glue and cleaner, we use oateys, or New pipe and fittings all together.

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