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  1. #1
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    How to repair crack in roof box

    The old Thule roof box is showing it's age. When I take it off in a few weeks, I already have to fix the front hinge, which basically rotted off at one point. But, yesterday I leaned on it the wrong way, and a small, three inch crack appeared at the stress point where it attaches to the rack in the rear. Not too bad right now, but, what can I do to seal and re enforce this crack so that it doesn't progress? Plastic repair is not my thing, especially for something that spends hard winters on the roof of my car.

  2. #2
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    I've got an old box I've been keeping going on life support. First, stop drill the crack (drill a small hole at the end of the crack). Locktite makes some plastic compatible epoxy I've had good luck with so far. Walmart carries it.

  3. #3
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    I have fixed lots of thule box cracks, they are all done on the inside so if you are careful you won't notice them, just tape the crack together on the inside with that sticky mesh drywall tape and slather on 2 part slowset epoxy

    broken/loose rivets are fixed with a pop rivet tool
    Lee Lau - xxx-er is the laziest Asian canuck I know

  4. #4
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    Quote Originally Posted by Benny Profane View Post
    Plastic repair is not my thing
    Neither is searching, apparently. .

    https://www.tetongravity.com/forums/s...ad.php?t=72296

  5. #5
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    West systems epoxy makes a Gflex kit specifically for plastic boat repair. Will work on your box too.

    The other method is plastic welding which can be DIY with the proper hot air welder or any body shop that has one.

    +1 to what SS7 said, (drill a small hole at each end of the crack)
    watch out for snakes

  6. #6
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    Quote Originally Posted by scottyb View Post

    The other method is plastic welding which can be DIY with the proper hot air welder or any body shop that has one.
    I would bet against this working ^^ thule box plastic is pretty thin, ever done it or had it done ?

    the good thing about the drywall tape or plain old FG cloth is that it also makes the repaired area stronger

    After 10 yrs/half a million km continually on top of a couple of cars I had > a doz cracks, some were self inflicted but eventualy the UV or vibration was causing multiple cracks for me to fix every summer until somebody stole the car/rack/box
    Last edited by XXX-er; 03-23-2014 at 01:08 PM.
    Lee Lau - xxx-er is the laziest Asian canuck I know

  7. #7
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    Not sure about Thule but Yakima recommends ABS cement. Seemed to work fine but can't comment on long term durability because my wife smashed the whole box into a thousand little pieces in her work garage a week later.....

  8. #8
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    I repaired a 2 foot area that was a spiderweb of cracks with two part epoxy and fiberglass cloth. That was five years ago and the repair is still in fine shape. I had some fancy-pants materials left over from a boat building project, but hardware store stuff will be just fine. Some of my repair has yellowed slightly, but it is still very strong.
    You should be able to purchase the materials for pretty cheap, especially for your small repair. I think on of those two part syringes that cost like 5 bucks should be enough. Buy the slow set epoxy. It will give you more time to work before it sets. Lightly sand, clean the area well and use latex or nitrile gloves. Cut your glass cloth the the proper size and practice positioning it dry. Mix a small batch of epoxy and wet the area. Lay the cloth down work it into the epoxy using a flexible tool or your gloved hands. It should turn almost clear. If not add a little more epoxy. Let it cure. It should be stronger than the original.
    Originally Posted by nickwm21
    "hitting rocks ain't normal use in their eyes..."

  9. #9
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    Quote Originally Posted by XXX-er View Post
    I have fixed lots of thule box cracks, they are all done on the inside so if you are careful you won't notice them, just tape the crack together on the inside with that sticky mesh drywall tape and slather on 2 part slowset epoxy

    broken/loose rivets are fixed with a pop rivet tool

    This sounds like an easy solution. I may do it all all four mounting points. Probably make it even stronger.

    The two rivets holding the bottom plate of the front hinge are rotted off (the inside part). I was just going to get a few short screws to replace them and glob on some epoxy on the outside of the screws to seal the thing off. Should I rivet again?

  10. #10
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    Drilling small holes at the ends of the crack is critical. I've used mesh tape/epoxy and I've used gorilla tape. Both worked really well. If the crack is pretty straight (not jagged like a lightning bolt) the gorilla tape worked on the outside. The more complex cracks required epoxy.

  11. #11
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    Quote Originally Posted by Benny Profane View Post
    This sounds like an easy solution. I may do it all all four mounting points. Probably make it even stronger.

    The two rivets holding the bottom plate of the front hinge are rotted off (the inside part). I was just going to get a few short screws to replace them and glob on some epoxy on the outside of the screws to seal the thing off. Should I rivet again?
    Rivets on my Hinges were just loose/missing/pulled thru but nothing was "rotten?" so I just cleared the holes and used pop rivets and it worked fine

    If you need to build up the hinge mount area's I would use the FG tape & 2 part slow set, screws might work but I would be more likely to build up and area with FG and epoxy and bolt right thru with stainless steel nuts and bolts if it could work without hitting anything, OR use pop rivets

    when you are glueing anything (exception being crazy glue & contact cement) you gotta stabilize whatever you are fixing until the glue glue drys which is why the sticky FG tape used for drywall repairs is good

    http://www.homedepot.ca/product/shee...140323213559:s

    just get everything pulled together close as you can, using ductape on the outside that you will remove later is good, its also a good app for using some of your favorite big stickers on the cracks

    Just spread the epoxy right thru the DW tape on the inside of the box and let cure 24 hrs
    Lee Lau - xxx-er is the laziest Asian canuck I know

  12. #12
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    Thanks.......

  13. #13
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    Any time oh profane one, I know shit about investment banking or money, even less about women and I don't own any loafers but I do know that ... I CAN fix things
    Lee Lau - xxx-er is the laziest Asian canuck I know

  14. #14
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    Quote Originally Posted by XXX-er View Post
    Any time oh profane one, I know shit about investment banking or money, even less about women and I don't own any loafers but I do know that ... I CAN fix things
    thinkin' it was Old Larry with the loafers, but i'd bet you could fix them too...
    Something about the wrinkle in your forehead tells me there's a fit about to get thrown
    And I never hear a single word you say when you tell me not to have my fun
    It's the same old shit that I ain't gonna take off anyone.
    and I never had a shortage of people tryin' to warn me about the dangers I pose to myself.

    Patterson Hood of the DBT's

  15. #15
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    Quote Originally Posted by dcpnz View Post
    Not sure about Thule but Yakima recommends ABS cement. Seemed to work fine but can't comment on long term durability because my wife smashed the whole box into a thousand little pieces in her work garage a week later.....
    Abs cement is great for fixing abs plastic. I use it to glue motorcycle fairings all the time. The great thing about it is that it melts the plastic and fuses it. Essentially strong solvents will melt abs. You can melt abs pipe pieces in acetone to create a goo that you can brush on.

  16. #16
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    ask how to pull and put duct tape on the box.
    b
    .

  17. #17
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    Quote Originally Posted by scottyb View Post
    West systems epoxy makes a Gflex kit specifically for plastic boat repair. Will work on your box too. +1 to what SS7 said, (drill a small hole at each end of the crack)
    I did this with my box this spring. I had left it on the backside of the garage over the winter, and the roof slid and really crushed it. I fixed it with G-flex spread over fiberglass mesh on the inside. I sanded and painted the exterior with a metallic Krylon paint which was a pretty good match with my vehicle's color. The repaired section (rear end) is way more solid and less flimsy than the undamaged front section

  18. #18
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    For anyone that cares to look there is a shiton of utoob vids on the subject. This is just one.



    In another the guys fixes an ABS motorcycle fairing with a soldering gun and strips cut from a clip board he got at Staples.
    watch out for snakes

  19. #19
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    more than one way to skin a cat as they say, I know epoxy and fg tape works cuz I've done it literaly dozens of times, adds to the structure and none of the repairs broke of course this didn't stop the new cracks from forming

    have you tried to weld the plastic of a thule box it seems pretty fucking thin ??
    Lee Lau - xxx-er is the laziest Asian canuck I know

  20. #20
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    I used fiberglass mesh tape and 24hr cure epoxy for a box I bought off of craigslist for cheap. Roughed up the inside with a dremel wheel so the surface would bond well. Drilled the ends of the cracks with a drill to keep the cracks from propagating. Has held up well for 1 year. I know this procedure has been described above, but now we have a beautiful photo!


  21. #21
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    Supa-Fix solution & reinforcing powder - the stuff is brilliant: https://www.youtube.com/watch?v=uoLUSM9zdkA

  22. #22
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    for super easy repair of small, minor cracks -- this stuff works great. Has lasted on 2 different boxes of mine over 6 years without fail. Adds strength and takes about 5 minutes to repair. Clean surface, cut patch to shape, heat, stick on patch .. wait and go. http://geminimaterials.com/patch-n-repair/patches

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