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What to do with old fat skis: Add fishscales??

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  • What to do with old fat skis: Add fishscales??

    It was my day off, I had gotten to tinkering with some bike gear, then while bumping around in the gear closet i came upon my project skis, a pair of old black Gotamas, the ones with the big upturned tail.

    I had picked these up for $5, they were pretty beat, so I had taken a file to them, flattened the bases, cleaned up the edges, did some ptex work, and cut off the tails and then they sat, awaiting the final insult: adding fishscales

    I used my Rossignol BC 125 as a reference ski as they have about the same length edge and base contact. The Rossis have ~32" of pattern centered at cord center. I feel like the pattern on the Rossi is a little too far forward for my binding mount, so I centered the scales on the Gots at edge center, which is also where I mounted the binding (BOF on EC). I decided to give the Gots 30" of scales, cuz I like the number thirty

    At some point I read on TGR where someone was contemplating the addition of fishscales on some old skis. In the discussion that followed, someone suggested heating a cheese grater and "pressing" the pattern into the skis. Well, I heated a grater until it was red hot, and it barely made a dent in the bases, but the grater was a nice way to mark a pattern... but for the rest of the marks I used a parmanet marker

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    Round two, the "dremelator": I used a medium sized grinding stone, set all the way into the chuck, then preceded to grind away ...

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    ...a long while later I started rethinking my grinding technique, because it was taking a loooong time!

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    So I tried a different technique on the second half of the first ski. Now, instead of plunging the stone into the ptex (which causes some ptex melting), I pushed it down and forward, in a sliding motion. This was waaaay faster and and left a much cleaner cut. I completed all of the scales on the second ski in same time that it took to do 25% of the scales on the first ski (~fifteen minutes) Notice how much cleaner the cuts are on the left vs the right:

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    Adding the binding, TTS Axl base:

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    The finished bases:

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    The whole shebang!

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    Last edited by Nurse Ben; 7 September 2013, 03:37 PM. Reason: Add Pictures

  • #2
    No, no, the cheese grater does not work, the ptex base is just too hard!

    The dremel is your friend, do some practice on a cutting board, get that sliding motion down, then bust it out!!

    About the only thing that worries me is if the pattern is too grabby, at which point I could probably wax it a bit for my slide.


    • #3
      I tried the cheese grater thing and it only worked on some skis and not others. It worked on some old Elans with a black base, but failed completely on other skis. I think there are different grades of P-tex and the ones it worked on were softer and possibly lower melting temp. Maybe extruded vs. sintered. You can try it and if it doesn't work, no harm done.

      Ben, I didn't really understand the difference between the ways you were using the dremel. Did you have the axis of the tool near horizontal or near vertical?

      If the pattern is grabby, try cleaning it up with a sanding block.


      • #4
        @Telenoober, I used the grater as a pattern, yes, but I failed to mention that I used a permament marker to make the marks on the ski base for the dremeling.

        What I did diffently when changed my dremel technique is that at first I laid the stone onto a mark and pressed down perpendicualr to the ski until the notch was done, this was slower and tended to overheat the ptex. The new and improved technique was to place the stone on the mark and push down as I slid the dremel forward, more like making a notch with a blade. I was able to go much faster and the ptex didn't overheat, so the cuts were cleaner.p

        The Gots must have very hard ptex because even with a superheated (glowing red) grater, I still got nothing more than small dents.

        The dremel is fast when you get the right technique. I wouldn't hesitate to do it again, but my next pair will be a lighter weight ski with some pop, Red Apples or similar, assuming that they work okay.

        @Polemonium, how did the pattern you made compare to a manufactured pattern?
        Last edited by Nurse Ben; 7 September 2013, 10:29 PM.


        • #5
          Nice job. I have made a few pairs of DIY fishscale skis. I found you have to be aggressive in making the cuts in order to get grip. I mad a simpler cut, essentially an edge running the width of the ski, repeated every 1/4 inch down the kick zone, cut with a cone shaped-dremel, held pointing to the back of the ski. I only had real problem with one set of skis, some teledaddy's, where the base shredded instead of cutting cleanly.


          • #6
            Melting the ptex...different techniques to get a clean it up with a sanding block? Those would be the least of my problems if I tried this in my kitchen and my wife came home before I was able to clean up the mess!!!


            • #7
              Melting the ptex...different techniques to get a clean it up with a sanding block? Those would be the least of my problems if I tried this in my kitchen and my wife came home before I was able to clean up the mess!!!
              Seriously, there was black ptex dust on everything!! I had to dust the entire kitchen, clean anything that was sitting out on the counters. Fortunately my wife is very understanding

              When we move, I get a workshop for my very own, so no more messing up the kitchen and laundry room


              • #8
                Originally posted by Nurse Ben View Post
                how did the pattern you made compare to a manufactured pattern?
                The cheese grater melted into soft ski base pattern left bumps as well as divots, so it required a lot of sanding down with a sanding block. It climbs well but can be grabby especially if the snow gets hard or crusty. Sanding down helped a lot. I also cut grooves into a hard-base ski, like the picture that Baaahb had posted to Ttips. Those grooves were kind of weak because I only have a weak knockoff rotary tool. So it didn't climb very well, but glide was fine. Even with this, some sanding clean-up is good. Of course, both look ghetto compared to a manufactured pattern.

                Both of these were my attempt to make a sort of burly XCD ski that I wouldn't mind treating badly, out of an old alpine ski. I live in Arizona so have to cope with bad snow, melt-out, walking across rocks, etc. For this, they were adequate. I would like to try this on a beater light-ish fatter ski, but it's hard to find such castoffs here.

                p.s. I'll drill skis on my living room floor, but ski-base melting and grinding is definitely an outside project.


                • #9
                  I think the best option is to beat
                  them with a meat tenderizer hammer..
                  seriously, wonderful results!!!
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                  • #10
                    Nice work N.B.

                    I used my dremel the same way to clean up the pattern of my beloved and beat down Guides, but due to a lack of gumption, never bothered trying to make a pair of waxless from scratch. Now I will. I guess the real issue is how thick is the ptex on any particular ski.....pretty easy to go right thru. But then again, if one is willing to do the DIY scale thing, then the Ptex repair to the self inflicted core shot shouldn't be an issue.

                    Now to go home and decide what pair will be the victim/patient.

                    BTW, which shape grinding tool did you use? I was thinking of using a couple different ones for a progressively deep pattern..........



                    • #11
                      I played with a couple differnt bits until I got the desired scale profile. Here's the bit I used:

                      It's a standard dremel grinding bit, aluminum oxide, ~15mm diameter.

                      I ran the bit all the way into the chuck on a 4000 Series Dremel Rotary, then I did a sliding motion to cut the notches.

                      I did get into the core in places, so I might see a bit of glass, but I'm not too worried about water infiltration on a ski ike this, esp since it's gonna get a beating


                      • #12
                        Thanks Ben

                        I'm going to play with a progressive/regressive depth pattern, maybe with different profiles etc. Pretty well reinventing the wheel for no reason except to re-purpose some old skis that haven't been feeling the love the last few years. That and it will somehow make me feel like a dirtbag............


                        • #13
                          Hey guys I've been experimenting with some different patterns made on my milling machine. Both fish scale style and louver like cuts all the way across the base. Always seem to get to much drag compared to my BC 125s. Mabey I need to space the scales further apart down the length like Nurse Ben did.


                          • #14
                            You can also cut half moons with a router with some packing under one side of the base.

                            High speed, light touch, to avoid grabbing/melting. Plunge router works best.

                            Two rows, moons side by side.

                            Start with less length of moons than you think you'll need. You can always cut more; it's harder to put the plakky back.


                            • #15
                              I've been experimenting with DIY waxless bases for years. This is my current iteration, a simple step base. The skis are beat up Trab Stelvio XLs, my spring/summer AT rig. It's a short pattern, designed for flats and low angle cuz I'm skinning on the steeps. This pattern works fantastic on frozen lakes, flattish roads, scooting around in meadows, etc. The best thing about this pattern is that it has virtually no effect on downhill performance in spring/summer corn, unlike grabby fishscales. I have noticed it sideslipping on firm, but not bad. I'll likely be milling a similar pattern into my Voile V8s. (I have Vector BCs and Charger BCs for when I want an aggressive fishscale.)

                              FTR, I used a 1" indexable mill on a vertical mill. Decambered ski to flat in a simple fixture, held ski in vice/fixture at 10 degrees.

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                              Last edited by Big Steve; 2 December 2013, 03:58 PM.