Results 1 to 33 of 33

Thread: Plastic Repair

  1. #1
    Join Date
    Nov 2008
    Posts
    21,505

    Default Plastic Repair

    So, Her Eminence has been gifted a passel of kayaks by her employer.

    They leak, they're in livery and they're probably going to become the bane of my existence this Winter unless I can figure out how to repair them.


    The idea that She has come up with is to have them coated with truck bed liner.

    If it works it's a great idea, because the leaks get sealed and the boats become all one color.

    Alternative methods would include figuring out where each individual leak, crack, gaping hole is, weld them shut, and apply a plastic-adhering paint.


    Oh, they are roto-molded plastic.

    Yes, I know. Google is my friend, but Google never drops by with a six-pack.

    Anyone have experience with this?

  2. #2
    Join Date
    Sep 2007
    Location
    Northeast
    Posts
    13,596

    Default Re: Plastic Repair

    Welding. Seriously. Look up plastic welders.
    "The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails."
    -William A. Ward



  3. #3
    Join Date
    Jul 2008
    Location
    Tacoma, WA
    Posts
    7,979

    Default Re: Plastic Repair

    How many in a passel?
    “What, Me Worry?". -. A. E. Newman

  4. #4
    Join Date
    Nov 2008
    Posts
    21,505

    Default Re: Plastic Repair

    Oh dear.



    Another tool and another set of skills>>>

    Oh, well.

    Life is hard.



    So, do you have any suggestions for locating the leaks?


    I'm thinking set the boats up high on a rack an run 20-30 gallons of water into them to see where it comes out.

    Right track? Wrong track?

    Jeezle.

  5. #5
    Join Date
    Oct 1999
    Location
    St. Paul, MN, USA
    Posts
    46,439

    Default Re: Plastic Repair

    Quote Originally Posted by oznabrag View Post
    Oh, well. Life is hard .
    Beats the alternatives, though.

    I'd set them up on something very low, maybe a couple of 2x4s, and run water into them. Then you can just turn them over to dump the rest of the water out. That would be harder on a high rack.
    "For a successful technology, reality must take precedence over public relations,
    for nature cannot be fooled."

    Richard Feynman

  6. #6
    Join Date
    Jun 2003
    Location
    Fredericton, New Brunswick
    Posts
    32,012

    Default Re: Plastic Repair

    Quote Originally Posted by Keith Wilson View Post
    Beats the alternatives, though.

    I'd set them up on something very low, maybe a couple of 2x4s, and run water into them. Then you can just turn them over to dump the rest of the water out. That would be harder on a high rack.
    Though less entertaining than the high rack. Which would also be useful if Oz's shower happened to be on the fritz.
    If I use the word "God," I sure don't mean an old man in the sky who just loves the occasional goat sacrifice. - Anne Lamott

  7. #7
    Join Date
    Nov 2008
    Posts
    21,505

    Default Re: Plastic Repair

    Quote Originally Posted by Jim Bow View Post
    How many in a passel?
    A passel is a parcel funneled through a broad Southern drawl.


    Sorta like a gizmo.



    Right now, I believe the count of this particular passel is 15.


    Ugh.

  8. #8
    Join Date
    Sep 2007
    Location
    Northeast
    Posts
    13,596

    Default Re: Plastic Repair

    Quote Originally Posted by oznabrag View Post
    Oh dear.



    Another tool and another set of skills>>>

    Oh, well.

    Life is hard.



    So, do you have any suggestions for locating the leaks?


    I'm thinking set the boats up high on a rack an run 20-30 gallons of water into them to see where it comes out.

    Right track? Wrong track?

    Jeezle.
    Makin' a shower?
    "The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails."
    -William A. Ward



  9. #9
    Join Date
    Nov 2008
    Posts
    21,505

    Default Re: Plastic Repair

    Quote Originally Posted by Keith Wilson View Post
    Beats the alternatives, though.
    Some of the pain will no doubt be assuaged through the acquisition of a plastic welder and the skills to use it effectively!

    Quote Originally Posted by Keith Wilson View Post
    I'd set them up on something very low, maybe a couple of 2x4s, and run water into them. Then you can just turn them over to dump the rest of the water out. That would be harder on a high rack.
    If you set this up on something low and outside (), you're rolling around in the mud looking for leaks.

    Getting excess water out of the boat after the leaks are located should be easy-peasy for a guy with a 12v pump and/or a knowledge of siphons.

  10. #10
    Join Date
    Apr 2007
    Location
    Caribbean cliff edge
    Posts
    14,758

    Default Re: Plastic Repair

    Quote Originally Posted by oznabrag View Post
    So, Her Eminence has been gifted a passel of kayaks by her employer.

    They leak, they're in livery and they're probably going to become the bane of my existence this Winter unless I can figure out how to repair them.


    The idea that She has come up with is to have them coated with truck bed liner.

    If it works it's a great idea, because the leaks get sealed and the boats become all one color.

    Alternative methods would include figuring out where each individual leak, crack, gaping hole is, weld them shut, and apply a plastic-adhering paint.


    Oh, they are roto-molded plastic.

    Yes, I know. Google is my friend, but Google never drops by with a six-pack.

    Anyone have experience with this?

    http://www.instructables.com/id/Fixi...-with-a-hole-/
    Enjoy a good rum on the rocks at sunset.

  11. #11
    Join Date
    Mar 2010
    Location
    central cal
    Posts
    10,577

    Default Re: Plastic Repair

    Dark room, upside down “kayak”, lightbulb inside. It’s a good way to find pinholes in SOF skins.

    Peace,
    Robert

  12. #12
    Join Date
    Oct 1999
    Location
    St. Paul, MN, USA
    Posts
    46,439

    Default Re: Plastic Repair

    Quote Originally Posted by oznabrag View Post
    If you set this up on something low and outside (), you're rolling around in the mud looking for leaks.
    Good point, although I have a paved driveway that's useful for that kind of thing, also grass. Of course, in not too long there will be snow up to my ears, a problem you're unlikely to have.

    That's a clever idea about the lightbulb, since holes and cracks look very different than variations in the plastic thickness. I'd try that first - OTOH, it only shows non-uniform places, and won't tell you if a scratch or other bright spot actually leaks.
    "For a successful technology, reality must take precedence over public relations,
    for nature cannot be fooled."

    Richard Feynman

  13. #13
    Join Date
    Apr 2000
    Location
    Southampton Ont. Canada
    Posts
    5,750

    Default Re: Plastic Repair

    Probably at the stern,from dragging and the bow, from rough landings.
    I'd leave it in the truck for the water test.Tip it up on one end and check the other end
    It's the right height to look all around.
    if its just a wee hole, drive screw into it.
    WEST G flex is supposed to work on poly.
    R
    Sleep with one eye open.

  14. #14
    Join Date
    Oct 2008
    Location
    Walney, near Cumbria UK
    Posts
    35,212

    Default Re: Plastic Repair

    I have hears of small leaky workboats given a new lease of life by wrapping them in plastic backed bitumastic roof membrane, similar to Bostic Flashband.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
    The weakness of the web: Anyone can post anything on the web.

  15. #15
    Join Date
    Jan 2005
    Location
    Deepest Darkest Wales
    Posts
    18,437

    Default Re: Plastic Repair

    You really need to know what kind of plastic - most rotomoulded boats are polyethylene - some of which are weldable some are not.

    Generally the cross-linked versions don't weld worth tuppence - there are other techniques.
    Someday, I'm going to settle down and be a grumpy old man.

  16. #16
    Join Date
    Jan 2004
    Location
    Nebraska
    Posts
    18,609

    Default Re: Plastic Repair

    I'd be dis-inclined to use the bedliner - would expect a significantly heavier boat. Plastic weld sounds most promising. How many boats? You opening up a rental service?
    There's a lot of things they didn't tell me when I signed on with this outfit....

  17. #17
    Join Date
    Sep 2007
    Location
    Northeast
    Posts
    13,596

    Default Re: Plastic Repair

    Quote Originally Posted by P.I. Stazzer-Newt View Post
    You really need to know what kind of plastic - most rotomoulded boats are polyethylene - some of which are weldable some are not.

    Generally the cross-linked versions don't weld worth tuppence - there are other techniques.
    Flame treating the (cleaned) surface of cross-linked polyethylene usually opens up the polymer chain structure enough to allow for successful welding.
    "The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails."
    -William A. Ward



  18. #18
    Join Date
    Aug 2006
    Location
    Rockford, IL
    Posts
    8,468

    Default Re: Plastic Repair

    Nothing will adhere to those Roto-Moldings except Plastic weld using the same type of polymer. Welding is the ONLY satisfactory fix.

  19. #19
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    20,992

    Default Re: Plastic Repair

    Set aside one as a test unit & weld with plastic (from this same donor?) & a torch. Takes some learning, but anyone who can braze can do it.
    "If it ain't broke, you're not trying." - Red Green

  20. #20
    Join Date
    Jun 2000
    Location
    Madison Wisconsin
    Posts
    8,540

    Default Re: Plastic Repair

    G-Flex will do it.


  21. #21
    Join Date
    Nov 2008
    Posts
    21,505

    Default Re: Plastic Repair

    Quote Originally Posted by Ron Williamson View Post
    Probably at the stern,from dragging and the bow, from rough landings.
    I'd leave it in the truck for the water test.Tip it up on one end and check the other end
    It's the right height to look all around.
    if its just a wee hole, drive screw into it.
    WEST G flex is supposed to work on poly.
    R
    Wouldn't THAT be nice! I actually have a small kit of G-Flex, and I think that will be my first stop.

    Thanks!

    Quote Originally Posted by P.I. Stazzer-Newt View Post
    You really need to know what kind of plastic - most rotomoulded boats are polyethylene - some of which are weldable some are not.

    Generally the cross-linked versions don't weld worth tuppence - there are other techniques.
    And those techniques are . . .?

    Quote Originally Posted by George Jung View Post
    I'd be dis-inclined to use the bedliner - would expect a significantly heavier boat. Plastic weld sounds most promising. How many boats? You opening up a rental service?

    I told her it would add at least 5 pounds, if not 10.

    She doesn't seem to care.

    And, yes, she does intend to open a boat livery.

    Quote Originally Posted by Canoez View Post
    Quote Originally Posted by P.I. Stazzer-Newt View Post
    You really need to know what kind of plastic - most rotomoulded boats are polyethylene - some of which are weldable some are not.

    Generally the cross-linked versions don't weld worth tuppence.
    Quote Originally Posted by Nicholas Scheuer View Post
    Nothing will adhere to those Roto-Moldings except Plastic weld using the same type of polymer. Welding is the ONLY satisfactory fix.
    Flame treating the (cleaned) surface of cross-linked polyethylene usually opens up the polymer chain structure enough to allow for successful welding.
    Contradictory claims?

    Quote Originally Posted by Garret View Post
    Set aside one as a test unit & weld with plastic (from this same donor?) & a torch. Takes some learning, but anyone who can braze can do it.
    All the boats are from the same manufacturer, so the plastic from one should be compatible with all.

    This is going either to be simple, or ridiculously frustrating and time consuming.


    I can deal with that.

    That's why she picked me!

  22. #22
    Join Date
    Nov 2008
    Posts
    21,505

    Default Re: Plastic Repair

    Quote Originally Posted by Todd Bradshaw View Post
    G-Flex will do it.

    WOO-HOO!!!

    Actually, that looks like the same kayak!


    Her boss has a bunch of dock monkeys who have tried to keep these things afloat, and G-Flex was one of their weapons.

    Maybe they weren't doing it right.

  23. #23
    Join Date
    Feb 2001
    Location
    Chattanooga, TN
    Posts
    18,114

    Default Re: Plastic Repair

    I've actually used fiberglass & epoxy to repair broken plastics on motorcycles before and then bondo and hi fill primer on the outside to clean it up.

    Chad
    There are three ways to do things: The right way, the wrong way and my way.

    Three Little Birds
    Love is My Religion

  24. #24
    Join Date
    Sep 2007
    Location
    Northeast
    Posts
    13,596

    Default Re: Plastic Repair

    Quote Originally Posted by oznabrag View Post


    Contradictory claims?


    Most certainly.

    <Off Topic>
    In a past life I had to deal with the design of medical devices. The plastics and elastomers that we used were pretty unusual in that they had to withstand repeated cycles of exposure to sterilization chemicals along with things like body oils and what-not and still stand up. Most of the plastics and elastomers that we worked with were known as "low surface energy materials" - in that NOTHING seemed to like to bond to them.

    What we discovered was that there were various surface treatments that would allow you to bond to this sort of stuff or to weld the materials together- including some cross-linked polyethylenes and the like. There was plasma treatment (expensive and difficult), some etching chemicals (nasty, cheap, bad for medical devices, but effective as all get-out), and finally flame treatment - take a torch and get the surface hot. With all of these treatments, you had to be Johnny-on-the-spot as you had a limited working time with the treated surface before it "reverted".
    <Back to topic>

    It is possible to treat the surfaces and yield one you can work with. It's a skill like any other.

    I've seen the claims about G-Flex, but haven't tried it for myself, which is why I didn't propose it.

    Worth trying. Worst thing that will happen is that it will peel off.
    "The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails."
    -William A. Ward



  25. #25
    Join Date
    Aug 2000
    Location
    Auckland ,N.Z.
    Posts
    23,540

    Default Re: Plastic Repair

    Quote Originally Posted by oznabrag View Post
    WOO-HOO!!!

    Actually, that looks like the same kayak!


    Her boss has a bunch of dock monkeys who have tried to keep these things afloat, and G-Flex was one of their weapons.

    Maybe they weren't doing it right.
    Probably mentioned or in there somewhere, but flaming it is important.
    No , seriously.

  26. #26
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    13,619

    Default Re: Plastic Repair

    I have a basketball hoop for my kids--yanno, the kind with the roto-molded poly base that you fill with water to provide a heavy base? When this gets run over by a Fed Ex truck, it cracks. DAMHIKT.

    I used JB Weld for plastic to a lay a thick bead along the several two inch long cracks.

    No leaks.

    That was two years ago.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  27. #27
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    20,992

    Default Re: Plastic Repair

    Quote Originally Posted by John B View Post
    Probably mentioned or in there somewhere, but flaming it is important.
    No , seriously.
    Oz is pretty good at flaming!

    "If it ain't broke, you're not trying." - Red Green

  28. #28
    Join Date
    Jun 2000
    Location
    Madison Wisconsin
    Posts
    8,540

    Default Re: Plastic Repair

    The flame is not to produce heat. I does some sort of mumbo jumbo polarization of the plastic which allows the resin to stick better. This is the way we have repaired sections of polyethylene ski bottoms for about 30 years. You use the blue part of the torch flame and a fast pass over the plastic. It does not get hot.

  29. #29
    Join Date
    May 2002
    Location
    MD
    Posts
    41,933

    Default Re: Plastic Repair

    Oh God you have my sympathy. Speaking as the guy who unloads and preps 60 kayaks a spring for rentals, repairs them and sells them six months later.

    First off don't use bedliner. Second don't come up with repair ideas until you have a clear understanding of what needs repairing. I haven't done plastic welding but have seen some scary looking backyard welding repairs that worked. Things like Tupperware lids welded onto a large v shaped crack. It's probably your most cost effective repair for large cracks and holes next to cutting them up and tossing into a dumpster. I've heard of people melting blue poly tarp into cracks.

    I have used g-Flex and talked to a guy who squeezed the last bit out of poly boats with regular laminating epoxy, glass and a heat gun. Sounded dicey but he said it works.

    Anyway to echo Rons advice most common holes are mischaracterized as cracks in the stern from dragging on the ground and the paper thin plastic shows a hole as a crack. After that actual cracks often show up under the seat area as many manufacturers try to reinvent the wheel every few years introducing unforeseen weak spots in seat supports/hangers/hull stiffening features.

    So, where are the hole(s)? Get or make a low sling stand or low horses. Pour in a few of gallons of water and lift the ends, tilt side to side. Mark off the sources of leaks. If they're just in the worn stern go ahead and cut the thin material out leaving maybe a 1/2"x 2"-3". Now you have a hole. Dry inside, clean and rough up the inside about 1/2". Cover hole w masking tape. Lift bow up 2' from stern and pour in 4oz of poxy thickened with a few bits of chopped glass onto hole from inside. Now's the fun part. Get a foot or so of 1" webbing, whatever kind you have. Get 2 or 3 1"x 1/4" ss sheet metal screws w big pan heads. Or like the screws used to attach the footbraces through the hull when machine screws aren't used. Fold over the webbing, put screws through it every 3"-4" then drill appropriate sized holes in the stern plastic/epoxy pour. Then mix up poxy and slather that folded webbing with it. Sometimes I've added cabosil. Ok, screw that mess into the stern pour and tape down the ends just so they don't stick up too much. When all is said and done you've got a kayak you can drag to your hearts content. The screw heads on asphalt should set most folks teeth grinding so that'll inhibit the practice. You could use Gflex on the exterior tape.

    The place where Gflex really shines is an actual single crack where glass can be applied on both sides. Roughen, pass a quick flame over it.

    Don't think of these kayaks as something "restorable", more like a plastic bucket that you can make workable. 50lb buckets.

    Have fun......

  30. #30
    Join Date
    May 2002
    Location
    MD
    Posts
    41,933

    Default Re: Plastic Repair

    Quote Originally Posted by switters View Post
    This is one time he should not flame, a hair dryer or heat gun will do.
    A quick pass with a flame is all that's needed, two seconds too long and Poof it's a gaping hole.

  31. #31
    Join Date
    Nov 2008
    Posts
    21,505

    Default Re: Plastic Repair

    Quote Originally Posted by LeeG View Post
    Oh God you have my sympathy. . . .
    Have fun......
    Got it.







  32. #32
    Join Date
    Feb 2001
    Location
    central, FL
    Posts
    13,701

    Default Re: Plastic Repair

    Unbelievable...... 33 posts already and NO one has come
    up with the only acceptable solution........










    Take the lines of one build wooden kayaks
    and send the plastic off to be recycled....
    Quote Originally Posted by George Jung View Post
    Don't under-estimate Jack. He's purty damned talented

  33. #33
    Join Date
    Sep 2007
    Location
    Northeast
    Posts
    13,596

    Default Re: Plastic Repair

    Quote Originally Posted by LeeG View Post
    A quick pass with a flame is all that's needed, two seconds too long and Poof it's a gaping hole.
    Yes.
    "The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails."
    -William A. Ward



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •