PVC solvent weld integrity question

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by bslbb, Oct 7, 2013.

  1. bslbb

    bslbb New Member

    Messages:
    2
    Location:
    Delaware
    Hi, I'm a new member here but I've been reading the forums for a long time and appreciate all of the helpful information!

    Today I was "gluing" a 1-1/2" PVC drain stub-out to the elbow in the wall using SCH40 PVC rated for DWV. Cut pipe using chop/miter saw for square cut. Deburred and beveled edge slightly. I prepped both parts with clear cleaner and purple primer, followed immediately by PVC cement (all Oatey brand) and applied using the documented procedure. Immediately assembled the parts and rotated 1/4" turn (the pipe was fully seated) and held it in place tightly for at least 30 seconds. Released it and it seemed fine, wiped off excess but I looked back 30 seconds later and it had pushed out about 1/8".

    So the big question is can I trust this joint? I'm hoping since it's for drain and not highly pressurized it will be OK otherwise it's going to be quite a bit of work to replace. But I'm looking for an expert opinion.

    Thanks,

    Bryan
  2. Terry

    Terry Administrator Staff Member

    Messages:
    14,911
    Location:
    Bothell, Washington
    I think you are fine with that. It's a solvent "weld"
    There is a bit a transference of the two fittings when the "glue" is used.
  3. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    The primer is all that's need before applying the PVC cement. There is no need for the cleaner.

    John
  4. DonL

    DonL Out of the Trades

    Messages:
    3,951
    Location:
    Houston, TX
    If you can not pull it apart it is probably OK.

    30 Seconds is not long enough in my opinion, just because of what you seen happen.

    Sometimes you can pull it apart and re-weld it.


    Good Luck.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,515
    Location:
    Cave Creek, Arizona
    An 1/8" is insignificant. Don't worry about it.
  6. bslbb

    bslbb New Member

    Messages:
    2
    Location:
    Delaware
    Thanks everyone for the feedback! I just checked it and the joint is very solid and there is no way I'd be able to pull it apart. So I will leave it as-is.

    John, thanks for the tip about the cleaner. Is that just a clear version of the purple primer?

    Don, the second joint I put together I held for about 90 seconds just to be safe. And that one stayed put...so I agree 30 seconds is not enough for this size pipe. For 1/2" it seemed OK though.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,923
    Location:
    New England
    The fitting is actually tapered. The larger the pipe, the bigger the tendency for it to push out. Until enough of the solvent evaporates, you have a slippery round pipe inside of a slightly smaller tapered one...it will try to push out if there isn't enough resolidified material to hold it in place. It gets worse if you apply excess cement - more solvent to evaporate before it solidifies. It can get quite frustrating if you aren't ready for it. It can be a major pain on something like say a toilet flange where it pushes itself up off the floor and is dangling there; best to have the screws ready and hold it down until you can get at least one screw in, or place a weight on it. Been there, done that...have had to cut apart a run to fix things, too...experience certainly helps, and most DIY'ers don't do it often enough to get the right touch, so it takes longer and doesn't look as pretty.
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,515
    Location:
    Cave Creek, Arizona
    The surface tension of the liquified glue is what pulls the pipe out of the joint unless you hold it long enough for adhesion to occur.
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