Bonding Epoxy to PVC PIPE

Discussion in 'Materials' started by michael pierzga, Jan 12, 2012.

  1. Submarine Tom

    Submarine Tom Previous Member

    Would Sicaflex or 3M 5200 not be a better choice for this?

    -Tom
     
  2. david@boatsmith
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    david@boatsmith Senior Member

    To me carbonizing it means scorhing it. This is not neccesary. Sch 40 PVC will lose its gloss with a torch ever so lightly passed over the surface. More difficult to describe than observe but the surface will change slightly and be less glossy. Then sand it and the bond will be stronger than the PVC itself. This is from West System's Tech support. They have done distructive testing on various epoxy/pvc bonds and this was their reccomendation. They will gladly forward you the test data. This technique does not work the same with Sch 80 PVC. We glue Sch 40 pvc regularly and have had good results, both with andwithout flame treating.We abrade with 40 grit for a good mechanical bond and if the joint needs extra strength we will flame treat it.
     
  3. PAR
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    PAR Yacht Designer/Builder

    Agreed David, it's more of an oxidizing process then a true carbonizing. You're not looking to burn the plastic, but just change the surface molecules a bit.
     
  4. souljour2000
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    souljour2000 Senior Member

    Um..this is interesting...kinda wondered about how epoxy would work...with any vinyl really...and also wondered specifically about PVC...so anyway..I'm gonna go and try PAR's recommendations..and the other guys who also said scratch,groove, and sand, more or less...from my own experiences..that would certainly seem to be the way forward with PVC and epoxy...asa plumber..I would say that purple primer may help too...but then flame as PAR suggested is accomplishing same thing...IMHO...would clean the carbon off well though...and finalize "etched/scratched/burned " PVC with acetone...
     
  5. michael pierzga
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    michael pierzga Senior Member

    I will check the plumbing shop for PVC primer. Local painter told me he flame treats pvc if he must awlgrip it. .

    To test the flame treatment, run water over surface . If the water beads the flame treatment has not been succesful. The water should sheet off the flame treated surface.

    Guess I need to test a bond. The PVC will be mounded as skids on a tender storage sled.
     
  6. Submarine Tom

    Submarine Tom Previous Member

    It's okay, just ignore my input, I'm used to it, I don't mind, really, carry on, it's fine, no problem, go ahead, silly me, what was I thinking, I have nothing to add, as you were, really, carry on, it's okay, I'm good.

    -Tom
     
  7. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    No ,Sika wouldnt be a good choice in this application.

    These pcv sled runners need to be rugged. I was hoping to split the pvc in half...a half round section... then run a generous Epoxy fillet to bond the pvc to the plywood tender sled. .
     
  8. cor
    Joined: May 2008
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    cor Senior Member

    HDPE pipe is a lot more "slippery" and tougher than PVC, if that is the type of service it is going to see.

    Probably harder to glue to than PVC though.

    C.O.
     
  9. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Of the hard plastics, such as PVC, styrene and ABS, a heavy tooth and "oxidizing" the plastic, just before epoxy application is the best route. The solvent used in PVC primer is usually MEK which will adversely affect the epoxy, it's cure and physical properties. Solvents used with PVC, are to literally change the surface molecules on PVC, so that the cement (which really isn't) can create a chemical weld.

    As to the use of polyurethanes like Sikaflex 292 or 3M 5200, you'll not be as satisfied with the results, so wouldn't be recommended. The elongation properties of these products would tend to help work the surface bond loose, unlike a more rigid material like epoxy.

    I've had very limited success bonding epoxy to the HDPE and UHMWPE. These self lubricating plastics, resist all but heat and chemical welding. I have used epoxy and mechanically keyed HDPE to it, with the use of a multiple dove tail slots, which the epoxy keyed to, but this is a purely mechanical attachment, even though there was some surface attachment involved.
     
  10. harry cassin
    Joined: Jan 2012
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    harry cassin Old Salt

    Iv'e just epoxy'ed PVC to plastic with just giving both surfaces a sand and it's rock solid
    5:1 mix.
     
  11. kent0405
    Joined: May 2012
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    kent0405 New Member

    If you really want to use epoxy, you must first sand the PVC well so that the surface will be roughen and after that, use acetone to clean it. You can already apply the epoxy once the acetone is dried. That PVC will mechanically bond.
     

  12. souljour2000
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    souljour2000 Senior Member

    This was a good thread...just re-visited it just now...good info..I am getting ready to attach a short stick of 1 1/4 pvc pipe to another LED anchor light which is built out of a 1 1/4 end pvc end cap with holes drilled for 15 led's...so I gouged and scraped and scratched the areas on both pvc fittings where the bond will be...and yes..I will again use acetone for a final clean after hitting both fittings for a just a second or two with flame from a blow-torch...No probelms with the first anchor light I did this way a while back...thanks for the good info..those who provided it...this site is the best and it doesn't get said enough..I am thankful to both the pros and amateurs or anyone who has the low-down on how to do a job right...and shares it with the world...or at least with us in here....;)
     
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