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  • Freerando mount issues

    I have a pair of Ski Trabs that have a botched mount job while mounting for NTN Freedom. I screwed it up last season and it's been collecting dust in the garage since it's not a needed ski but I should complete the mount sooner or later.

    I'm trying to mount them with BF inserts and found two issues:
    1) The wood quality around the underfoot area for mounting isn't that great. The wood is soft and when I first did it I swear I encountered a couple of voids. The skis are suppose to be regular wood underfoot for a strong mount.
    2) Due to the wood quality, threading for inserts tend to drive the inserts very deep. This just exacerbates any misalignment problems.

    My plan now is to back out the bad insert holes, plug them with a hardwood dowel w/ JB Weld + steel wool, let cure and then redrill and reglue with JB Weld+steel wool. I would think that plugging this way should be fairly bomber, esp since there are 6 screws holding the NTN Freedom down to each ski.

    Still, it makes me a little nervous about the mount. Should I trust these cores? I did buy them at a discount new but still fairly expensive at the time ($400+). I'd consider selling them but now one of the skis has like 20+ holes in it.
    Drive the cuff!

  • #2
    Since I'm tossing around posts today, what the heck. Recent discussion with one much more informed than I am dealt with how the engineering of threads relies on very few for resistance. Say three. Call the rest fallback, but really shouldn't need them. Ergo, much below the "binding plate" doesn't matter that much. Could be foam. So first make sure there isn't a metal layer or super plastic here. If not, and it's all wood then:

    Forget JB Weld. It is a non-penetrating, high temperature application, epoxy putty. If you want to fortify weak wood, way better to use slow set regular laminating epoxy that will penetrate the wood. The steel wool "rebar" only makes sense if you are trying to re-set in an oversize hole (& In My Guess, chopped fiberglass serves just as well). If you are inserting a hardwood dowel, either would be counterproductive--too thick. Lastly, don't get a dowel. Get a drill bit that will create a hardwood plug to size. That way you can set a plug with grain to match the core. A dowel has you screwing into end-grain.

    I once filled a screw hole on an XC ski with glue. Filled & ...it never filled. Was probably an intentional honeycomb.
    nee, Whiteout

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    • #3
      Charley, so let me get this straight, your suggestion is slow set epoxy and a hardwood plug inserted where the grain follows the ski length? Skip the steel wool rebar?

      I've done lots of hardwood dowels for plugs before and they seem fine.
      Drive the cuff!

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      • #4
        Originally posted by SoMuchBetterThanU View Post
        Charley, so let me get this straight, your suggestion is slow set epoxy and a hardwood plug inserted where the grain follows the ski length? Skip the steel wool rebar?

        I've done lots of hardwood dowels for plugs before and they seem fine.
        Well, if you're inserting a hardwood plug, I assume you want it to fit snugly, not float in a thin epoxy/steel wool surround. Otherwise, just skip the plug and "cast" the screw in place? As with any wood glue junction, the harder the wood contact and thinner the glue layer, the better. And align the grain with the ski grain isn't what I should have said. Just that screwing into "side" grain--however oriented--is much stronger than into "end" grain. Think of nailing a board to the ends of joists as opposed to on top of them. OTOH, if you've been going into endgrain on hardwood dowels succesfully so far, no problemo!

        Edit to add--fill the hole & let penetrate the soft wood for a while. Soak up excess with a pipe cleaner & paint dowel with epoxy before inserting. The hardwood won't take--nor need--much penetration. Then let it cure in your house (or warm place), not a cold garage! (cold=weak to no cure.)
        Last edited by Charley White; 30 November 2013, 10:34 PM.
        nee, Whiteout

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        • #5
          SMBTU,... how about a few pictures.... I pretty much agree with everything Charley said, but sometimes pictures help explain what words can't convey.
          the fall line is your friend.... resistance is futile

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          • #6
            Well there's not much to take. The skis have some pretty big holes and none of the voids are visible. I think the only other thing to note is that wood seemed a little soft. I may have to shim some toothpicks between the plugs and wedge it in there. I'd feel more comfortable if there was something exerting pressure between the wood and the plug.
            Drive the cuff!

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            • #7
              Huy--so the holes are substantially bigger than your wood dowel... An idea--haven't done it exactly but something similar many times: hammer a bunch of match sticks into a wood hole with wood glue. Cut two plugs to length from the dowel. Then split them like firewood. Then 4+ around circle and jam some in the middle. Might get a dense pack and better than soft toothpicks.
              nee, Whiteout

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              • #8
                Yeah I've always done the toothpicks on the outside of the plug. Gives me ideas tho. Another possibility:

                Drill a hole in a board the size of a smaller diameter dowel. This is the center of the plug.
                Drill/cut out the plug. Now you have a donut shaped plug.
                Split the plug in two directions like a cross to get 4 corners.
                Lay epoxy down in the hole
                Place the 4 corners into the hole and push the dowel down the center. This puts pressure in all 4 directions
                Plug the remaining gaps with toothpicks or shims and scraps

                I suppose another option is not to cut all the way through the donut plug and let the action of jamming the center dowel down to force the corners outward. It would be ok if the plug wood breaks.
                Drive the cuff!

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