Fin blade rails, water channeling and tendon rails explanation

  • Hi Dan,

    I know it's been a while since there was any movement on this topic. But I have a query over the T-rail that is used to hold the blade to the foot pocket tendons.


    Brief: - I have a pair of C4 Falcon Blades in Medium with Mares Pockets.


    My blades have scuffs and scratches and have had the odd bump. The blades themselves are fine other than aesthetics and having read all the complaints about them breaking so easily I am pleasantly surprised that they haven't.


    What has happened is that the T-rails that hold the foot pocket tendons to the blades have cracked in multiple places. I noticed during a session where the tendons started to pull away from the blades. The now short sections of the T-rails pulled off the blade in the tendons leaving them loose.


    I made some temporary fixes on the boat by super glueing the pieces back on, but now want to get the problem solved properly.

    I bought a T-rail section from a local shop and had it delivered. I believe it is a Salvimar T-rail and the only stuff I could find in Europe other than what C4 has promised to send me. (Still waiting)


    But on closer inspection the T-rail material I bought is quite a soft rubber. The sections I have removed from the blades are a very stiff and brittle material.

    (Logically them cracking in to small pieces as they have done is as expected...because they don't seem to have any flex but lie in an area where the blades are still flexing)...So surely a rubbery flexible material makes more sense unless the aim is to stiffen up the blades...


    Can you give me an idea what you would expect and what you have found to be the best as I know you have spent a lot of time on T-rail design.


    Attached are pictures of the rails broken on the blades and then samples of the rails.

  • Hi,


    As you know the foot pocket rails have specific qualities as far as shape, stiffness (measured in the Shore scale) and how well they bond to the epoxy saturated carbon surface using Cyanoacrylate glue. I'm not familiar with the rails you're using. I just know that these ones work well https://spearfishing.store/fin…foot-pocket-fin-rail.html. 5ft which is enough to refinish a pair of fins ships in a light padded envelope, so first class international mail to your country will be around $8 and take two weeks.


    I prefer to replace the complete rail because if a small section is in bad condition the rest of the rail is not far behind. But I have replaced small sections in the past with good results.

    The blade surface should be well prepped, all rubber and previous gluing residue completely scraped off. Use a blade for removing the bigger chunks of material, then a Dremel tool with a grinding stone or sand paper to remove the leftovers. Right down to the blade surface which will end up being scuffed, but only in the area that will be covered by the rails. Clean dust off with acetone.

    Then it's a matter of laying down a bead of Cyanoacrylate glue, positioning the rail, running your fingers tightly along the rail to create a wicking effect to distribute the glue, and clamping the rail along its entire length for a couple of minutes.

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