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Fixing Cracked Hubs On Plastic Wheels

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  • Fixing Cracked Hubs On Plastic Wheels

    If you run your cars with stock wheels this is bound to happen one day: you'll crash hard, the hub will crack and the wheel will fall off.



    There is hope. First, you'll need to make a trip to the hobby store/Canadian tire to pick up a few things to fix this common problem:
    • pin vise with small drill bits
    • small tubing cutter
    • set of hobby files
    • toothpicks
    • styrene cement
    • styrene tubing
    • CA glue
    Sure, the price of these items adds up to more than a set of aftermarket wheels, axle, and tires - but you'll be able to use them to fix other things, and you'll be able to fix any car that has this problem in the future.

    First, drill a tiny hole in the hub of the wheel.



    Why? Just do it already. You'll see why. Trust me.

    Next, get the styrene tubing. Choose a size of tubing that fits snugly over the cracked hub. Best to bring the wheel in question to the hobby store so you can choose the right size. You may need to file out the inside of the tubing to get it to fit over the hub. Once the tubing fits, cut off a piece the same length as the hub of your cracked wheel.



    The tubing cutter is your friend here. Mine was seven bucks at Canadian Tire. You'll get straight cuts every time, and you'll find lots of different uses for it. This works great on brass tubing too.

    Next, file the burr off the piece of styrene you just cut off and make sure it fits onto the hub. Then, apply a drop of styrene cement to the inside of the tubing and smear it around the inside of the tubing.



    Push the tubing onto the cracked hub.



    Next, apply a drop of CA glue inside the hub.



    Push the wheel onto the hub. Remember the hole you drilled? Check it out:



    The excess CA glue (and any air that would otherwise be trapped inside the hub) squeezes out of it. If the air weren't evacuated from the hub, the wheel would eventually fall off again. Wipe up the excess glue and you're done. Give the works a few minutes to dry and you're ready to race.

    Van
    Last edited by dr vanski; 04-11-2008, 10:51 AM.

  • #2
    those XKRS wheels shore are pretty

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    • #3
      Thanks for the show and tell. Nicely done. Probably the only 'fix' for those cars with knurled axle ends if you don't want to buy the entire rear axle/gear/wheel assembly.

      It also helps on those cars with smooth axles to just buy replacement wheels if they are available. I've done so on a number of Fly and Ninco cars.

      Scott

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      • #4
        Fortunately the knurling on the Jag axle isn't too big. I've had to junk quite a few Scaley T/A Mustang rear axles because of that. It was impossible to get the wheels back on straight and concentric.

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        • #5
          Double post: sorry

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          • #6
            Alternate method for the air hole location: from the inside of the wheel, angle the pin vise and drill bit from a point near the rim and drill towards the center of the axle hole, ending at the furthest recess of the axle hole. That still provides an escape path for the air and excess glue, which seals the angled hole, but you can't see it from the outside of the wheel. Prettier, because the outside of the wheel hub, where the nut or knockoff is located, remains intact.

            You can also add further reinforcement from a metal tube, over the styrene tube, or in place of it.
            Last edited by JML; 04-11-2008, 03:27 PM.

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            • #7
              So that's why my wheel came back off no air escape hole. Thanks guys. Now to buy a pin vise and tube cutter.

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              • #8
                As a former plastic modeler, let me put in a plug (no pun intended) for the cyanoacrylate glues that are sold as non-blooming or non-fogging. These are formulated differently from the run-of-the-mill glues, so they don't leave that white powdery or waterspot-like deposit around the area glued. Available in several viscosities, from many makers. You don't want to ruin that pretty wheel, or that smooth axle, from the redeposited vapors that fall back to the substrate.

                It seems you can't get this property in the "rubber-filled" variants of the glue (which are are more flexible), but you can increase the bond strength by working with clean metal and preparing surfaces by using the right glue primer. That's not the same as using an accelerator, which can also increase bond strength, but which can also damage adjacent materials. After the cyanoacrylate is used, let that cure for a day before using the part, to achieve maximum strength. Or use accelerator, sparingly (drop it on from a toothpick, don't spray it on).

                And it's probably a good idea to let the regular plastic cement and styrene tube cure overnight or for 24 hours before drilling a hole or gluing the wheel to the axle. I think the best styrene cement around is Faller Super Expert.
                Last edited by JML; 06-01-2009, 10:08 AM.

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                • #9
                  Great tutorial Doc. And the additional comments are much appreciated, too.

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                  • #10
                    Thanks

                    I have a FLY 917 porsche that has a rear wheel on a smooth axle that has popped off again. I will try the "escape hole" is the wheel rim as I've got the pin vise and the tiny drills to make the hole. Also, what about Loctite?


                    Roger

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                    • #11
                      I've had Loctite dissolve the plastic of some wheels - Scalextric I think. No problems with CA using this method.

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                      • #12
                        Most Loctite (& other manufacturer's) threadlockers are formulated to cure in the absence of oxygen, unlike regular cyanacrylates, and the chemical action of the cure does attack plastic. Loctite does make a threadlocker for plastic-to-plastic or plastic-to-metal use, however:
                        LoctiteŽ 425™ Assure™ Instant Adhesive, Surface Curing Threadlocker
                        Low viscosity, threadlocking, one part, room temperature cure, instant adhesive designed for locking plastic to plastic and plastic to metal fasteners.

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                        • #13
                          The ol'poke-hole trick eh? Nice work, I'm gonna try this tip.

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                          • #14
                            I thought the correct method was to put the drop of CA glue on the end of the axle

                            I have also read that one can wrap cotton thread tightly around the outside of the hub, then coat with CA to reinforce.

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                            • #15
                              I don't think it really matters if the glue is on the axle or wheel. The fact that glue eventually squirts out of the relief hole indicates that it is spread around inside the wheel hub. Sleeved tubing is a good way to repair split body posts as well.

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