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  1. #1
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    Want to know a bit more about ski boot plastics?

    Greetings distinguished TGR gear heads,

    I recently sat down with Blister Gear Review and recorded a podcast about the plastics we use in ski boots and how this relates to your skiing experience. This is actually part 1 of 2 (it was too long to release as one podcast) and we'll drop the second half next week, which will deal more specifically with topics of flex, damping, progression, etc.

    So, if you feel like getting nerdy about ski boots check it out! (I'll try my best to answer any questions that come up along the way too)

    https://blisterreview.com/gear-101/a...plastics-ep-54

    Cheers
    Matt

  2. #2
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  3. #3
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    Matt (and Jonathan), thanks for putting this out there and making it accessible. You could spend weeks doing Internet research and not come up with this much coherent information.

  4. #4
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    I happened to listen to ep 63 yesterday and was curious if this follow-up ever came to fruition. The original interview was great and really interesting; I'm very excited to hear these too as well.

    One random question for you - are the lower shells of the XTD and Hawx Ultra 130s made from the same mold?

  5. #5
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    thanks, will listen soon.


  6. #6
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    Cool. Looking forward to listening! Thanks for taking the time.

  7. #7
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    Quote Originally Posted by alpinevibes View Post
    I happened to listen to ep 63 yesterday and was curious if this follow-up ever came to fruition. The original interview was great and really interesting; I'm very excited to hear these too as well.

    One random question for you - are the lower shells of the XTD and Hawx Ultra 130s made from the same mold?
    normal Ultra and Ultra XTD use different molds because of having things like tech inserts, different soles, a ski walk mechanism, etc., but the last dimensions (i.e. the fit) and geometries are the same.


    Glad you guys are digging it so far!

  8. #8
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    So 100 kilograms of Grilamid costs roughly 4 times what 100 kilograms of True Flex PU does, but you need less of it by weight to build a shell of comparable stiffness?

  9. #9
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    Have you tested any of the new Francesco Franceschetti Elastomeri stuff, or is that the "outlier" you talk about?

  10. #10
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    Quote Originally Posted by gregL View Post
    So 100 kilograms of Grilamid costs roughly 4 times what 100 kilograms of True Flex PU does, but you need less of it by weight to build a shell of comparable stiffness?
    The mold has a set, unchanging plastic thickness, so if we make a Hawx Ultra in Grilamid or PU the same amount of plastic is required.

    Hawx Ultra is thinner than Redster World Cup, so in this comparison, less plastic is required to make the Hawx Ultra. But, the plastic in Ultra is more expensive and the molds are far more complex & costly. And to arrive at the same "130" between the two boots, we need to use a way stiffer PU in Ultra (because it is thinner) and a much softer PU in Redster (because it is thicker) to arrive at roughly the same stiffness. This exact topic is covered in the second podcast that drops next Friday (the 5th).

  11. #11
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    Quote Originally Posted by gregL View Post
    Have you tested any of the new Francesco Franceschetti Elastomeri stuff, or is that the "outlier" you talk about?
    We have experimented with some of those plastics, but we currently don't use them.

  12. #12
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    Quote Originally Posted by onenerdykid View Post
    This exact topic is covered in the second podcast that drops next Friday (the 5th).
    Will tune in for sure. Getting this straight from you is $$$. Should be required listening for anyone who calls themselves a bootfitter.

  13. #13
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    Sep 2014
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    Podcast downloaded and will be listening during my day's session of gravel and grass skiing. Can't wait!

    Until later....Any guesses how much a one off, custom, light weight carbon fiber version of this amazing piece of creativity would cost?

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    What if the hokey pokey really is what it's all about?

  14. #14
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    When will we finally get WIDEscale adoption of a boot sole and binding wing DIN footprint that's wider like today's skis are. I realize it would never work for FIS race skis but for everything else, why the hell not??
    Go that way really REALLY fast. If something gets in your way, TURN!

  15. #15
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    Quote Originally Posted by SumJongGuy View Post
    I realize it would never work for FIS race skis but for everything else, why the hell not??
    Much more weight for a dubious increase in leverage is my guess.

  16. #16
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    At present the maximum width for alpine boots is 69mm plus or minus 2mm, as specified by ISO 5355 (actually there is a new ISO 5355 document this year, but I don't want to spend 138 Swiss francs to find out what changed).

    Maybe Matt can tell us what is different from 2005.

  17. #17
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    Fascinating podcast.

    Coupla questions:

    1. Regarding the different plastics; I have no formal training in boot fitting. Employing tips gleaned from internet research and from generous knowledge imparted by TGR wise men, have had some successful results with some quite dramatic punching and stretching of shell material of personal ski boots. Initially, shell plastic was heated by 'feel', more recently a laser thermometer was employed to measure where I felt the subjective ideal temp was and quantify it with objective data to be used for future punching efforts.

    Is there a common reference 'chart' of some sort for optimum punching/stretching temps for the various types/blends of plastics referred to in your podcast discussion? Or are the various blends for individual manufacturers so varied that such a chart is not possible? I assume if a customer had the interest, one could contact an individual boot manufacturer and eventually gather the data...but can be time consuming.

    2. Regarding flex characteristics of various plastics: Why is the plastic shell material relied on for the desired flex characteristics of a ski boot? Wouldn't it be advantageous to construct very rigid shell sections out of carbon fiber, for example, with discrete, adjustable/variable forward and lateral flex and/or damping mechanisms?

    One can envisage a boot that is quite light yet perform with adjustable flex curve and damping for differing conditions, temperature ranges, body weight (days skiing with a heavy pack vs. no pack) and/or just sheer personal preference. I've had a modicum of success customizing some Dynafit Vulcan ski touring boots and modifying the ski/walk mode mechanism so that in forward flex the upper rear cuff canada arm buckle/lever locking alu knob squeezes a rubber plug to improve progressive forward flex and damping, while retaining rigid, firm rear support. It's still in rough experiment stage and rubber durability is the limiting factor, a.t.m. With the Vulcan at least, it seems like a large portion of the forward flex stiffness and character is derived from the rigid carbon rear cuff so perhaps the mod is more specific to this boot.

    Having felt that level change improvement in forward flex feel, it got the brain thinking about a different approach to ski boot shell design...just curious if there's been some experimentation in this department and if results hold any promise.

    3. In a recent shell punching/stretching session, I used a system of ziplock bags loaded with snow to apply to heated areas to quickly cool them, check for fit and re heat and push the shell further to reach desired width increases for medial and lateral fore and midfoot areas. This system was very time efficient. Are there any liabilities regarding some unforeseen negative effects on the different shell plastics described in the podcast when using this system? For example, could this approach compromise strength/longetivity of the plastic, inviting premature wear/reduced 'flex cycles', alteration of inherent stiffness and/or potential for cracking in the long term?
    Last edited by swissiphic; 07-05-2019 at 12:20 PM.
    What if the hokey pokey really is what it's all about?

  18. #18
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  19. #19
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    The biggest takeaway from the first episode was that different shades of red boots are faster than others, and your boots can really be too red.

    Kidding aside, that was a good listen. Probably the most I've learned in a podcast in recent memory.

  20. #20
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    I bet Hanson was a Trojan Horse for the Silicon industrial complex

  21. #21
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    Iím going back to red boots. Got to be faster


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