Glue preference

Discussion in 'Irrigation' started by Dirty Water, May 8, 2005.

  1. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    I've always used IPS 725 Wet Or Dry without primer on 1 1/4" PVC and smaller:
    [​IMG]

    And IPS Blue-Azul with Purple Primer on 1 1/2" and larger:
    [​IMG]

    Each glue joint is wiped clean of extra glue with a rag, so theres no mess, and no glue to eat into the pipe and weaken the glue.

    What is your preference?
     
  2. Planter

    Planter LawnSite Member
    from Utah
    Posts: 214

    I have never liked wet or dry, except in an extreme emergency when I had to get the line up. I have used 721, but only on 1" or smaller lateral lines. Hot Blue Glue is in the same category as wet or dry for me.
    I am doing commercial system repairs on about 50 properties. We constantly get solvent cement failures at fittings. Mostly mains or sub-mains with a cement that doesn't call for a primer.
    My preference is 711 for all work with a primer. I will use 721 on 1 1/2" or smaller laterals on occasion. The thing that I have found watching my co-workers is that most don't follow the manufacture's instructions. I had an 1 1/2" sub-main break loose at a fitting yesterday, they used 711 and there was NO evidence of primer. It held for five years, then came loose. Job security for me.
    I am also seeing a lot of failures in the pipe at a cemented coupling where the cement was left to bead on the pipe. It is weakening the pipe and failures are happening at the bead that shouldn't happen at all.
     
  3. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    I have probably glued at least 10,000 fittings with Wet or Dry and have never had a failure. We also pull all of our pipe, so theres a lot of stress on our joints.

    Its not the glue, unless your in a lot warmer of climate than me. Perhaps your technique is different?
     
  4. 725
    P-70
    Ditto
     
  5. jerryrwm

    jerryrwm LawnSite Bronze Member
    Posts: 1,274

    725 is my cement of choice. Use primer on mainline and sometimes on larger laterals. I think the label recommends that you use primer all the time.

    Christy's Red Hot Blue Glue for those times when the water will not stop running and you want it to set 'right now!' You better be twisting the pipe as you put it together with Christy's. Don't wait to let it bottom out - that's too late! Use sparingly - costs around $8.00 a pint. I won't buy a quart cause I'm prone to knocking cans over when I get my fat butt out of a hole.

    As for beads of cement around fittings, a swipe with the primer dauber gets it off, and also let's you know that you finished that joint.


    Jerry R
     
  6. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    A clean shop paper towel cleans 725 off just fine. Primer softens the pipe, and can create a weakspot years later.
     
  7. jerryrwm

    jerryrwm LawnSite Bronze Member
    Posts: 1,274


    Gotta disagree a little bit. The weakening is caused by the cement bead which skims over as it is exposed to the air, and finishes drying from the inside which continues to work on the piping. This is what causes the weak spot.

    Primer, being mostly acetone begins the cement welding process, and then dries away. The purple that is left is merely the coloring. Acetone dissapates rapidly and does not cause the weakening.

    Jerry R
     
  8. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    Just hairsplitting, but IPS website:

    "P-70 PRIMER PURPLE/CLEAR: The most aggressive primer commercially available. Excellent product for cold weather applications. If used properly, will soften the surfaces of PVC and CPVC pipe and fittings which is necessary for the proper solvent welding of the materials. Meets ASTM F-656 & SCAQMD 1168 Industry Listings: NSF, UPC (Purple only), LOW VOC with 3 Year Shelf Life."
     
  9. jerryrwm

    jerryrwm LawnSite Bronze Member
    Posts: 1,274

    The primer is softening the surface of the pipe which has a sort of glaze caused by the manufacturing process. It begins the solvent welding process which allows the cement to react with the PVC and continue the melting (welding) process. If as I said earlier, when the primer is put on the surface it will soften and then dry (evaporate). Once it dries the softening process ceases. That's why I find it humorous when I see someone 'pre-primering' the fittings so they can be ready for use in the future. They might as well just spray paint them purple for all the good they are doing.

    Cement on the other hand is slower to dry and cure, and after forming the skim on the surface, continues the reaction with the PVC material until it dries (cures). This is what causes the weak spots at the fitting hub.

    Jerry R
     
  10. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    Thanks for the consice explanation :) :cool2:
     

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