Let the Boot Fitting Commence — Zzero Round One

Post by WildSnow.com blogger | November 20, 2007      

The “new” thing in thermo liner molding is to heat the liner while inside the boot, with an expensive ($300 pro price) blower system that you’ll generally have to seek out a dealer to find. Not only will that entail dealing with store hours and finding the person who actually knows what they’re doing, but re-molding will require repeated trips to the store — with the aforementioned hassles.

Home baking liners is a tradition in the backcountry skiing community, so why this back step? It is indeed nice to heat the liner in the boot. It stays lasted (shaped) and holds position so you don’t have the issue of quickly, but nonetheless carefully placing the liner in the shell before it cools. But, and it’s a big BUT, if you’re molding with custom footbeds you’ll probably need to remove the heated liner from the boot, put your ‘beds in, then stick the liner back in the boot — thus actually making the process more complex by adding one more step.

Zzero backcountry skiing boot fitting.
Dynafit Zzero boot with my homebrew blower system. It didn’t work.

Still, this being the WildSnow.com World HQ of backcountry homebrew, for round one of fitting my Zzero “Green Machines” I tried to cobble up a blower system for heating the liners. After all, one has to be loyal to the innovations and standards of the industry — at least to the point of giving them a shot. My homebrew failed, but I learned quite a bit in the process.

(Note: I skied in the Dynafit Zzero a few weeks ago but used them without molding the liner. I can’t wait to get them tuned up and really cranking! Exciting.)

We’ve got a temp adjustable heat gun and an accurate infrared “gun style” thermometer. A quick trip to NAPA yielded a chunk of heat resistant tubing that fit on the end of the heat gun. I cut some slots in the tube to distribute the heat, stuck the rig in a boot, and fired it up. I got the temperature right (around 250 degrees) by experimenting and grabbing multiple readings with our thermometer “gun” (nice tool, by the way, highly recommended), but couldn’t get the boot to heat evenly. After fiddling around till the point of diminishing returns was reached, I grabbed our convection oven and went back to the standard method. Doing it that way worked fine, so that’s the upside of this experiment.

Conclusion: Don’t let the “new” way of molding liners scare you away from home baking. Sure, if you can find a store with the gear and a helpful human, go for it. Otherwise, excellent cookbooks exist such as this one. More, since we tend to regular blogs about boot fitting, I made a “Boot Fitting” category in our category index in the sidebar to your right. Here is a quick link to our Boot Fitting category index.

Noon today, this came in from Scarpa and I found it worth publishing and commenting on:

Lou, to assist people with getting a proper fit, SCARPA made a shell fit tool this season, taking the mystery out of using your fingers to fit shells sizes. We are making these available to retailers and they are also available through SNA. Since people have fingers of different thicknesses, that method is inexact to say the least. So SCARPA had a tool made that slips behind the heel. When placed behind the heel in one direction, it measures the upper end of how much room a skier should have in a shell (standing flat in the shell with toes just in the front of the shell). Rotated on its side, it measures the minimum amount of space one should have in a shell fit. So it’s easy to get an objective standard for how much room a person should have in a shell fit.

I’ve seen that Scarpa tool and it’s a good idea. Would be easy to make one for home use, dimension is 14 x 20 millimeters. Regarding stacked fingers, this is indeed imprecise but since everyone’s foot volume is different the “space behind the heel” method is only a starting point for boot fitting, not the end-all be-all. Thus, my take is that the stacked fingers is still valid — though the fit tool would be nice. BTW, can anyone find this on the Scarpa website? I’d like to link to it…

Another addendum: If you do use custom foot beds, another method of getting them into the heated liner is to hold them on your foot with a nylon stocking, then insert foot/footbed into the heated liner while the liner is in the boot. Using this method would be perfect for working with liners heated by in-boot blower.


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17 Responses to “Let the Boot Fitting Commence — Zzero Round One”

  1. Paul November 20th, 2007 10:23 am

    Thanks for the new category Lou. Unfortunately for me, it was an hour after I spent this am poking around on your site trying to find all of the posts related to boot fitting. I think you might have missed one in the category:
    Thanks again.

  2. Lou November 20th, 2007 10:28 am

    Paul, I knew I needed to hurry up and get that done! Sorry it took me so long. I’ll add number 72. Thanks, Lou

  3. Paul November 20th, 2007 11:16 am

    Thanks Lou.

    Number 72 has the most important piece of information, the finger stack:
    “Any more than a 2 finger stack and the backcountry skiing boot shell is too big. Less than one-and-one-half fingers and it’s probably too small. “

  4. Michael November 20th, 2007 12:35 pm

    It was just suggested to me by a boot retailer to ski new boots for a few days and not cook the liners. She suggested that cooking the liners just hastens the breakdown process of the foam and skiing them will do the same thing, more slowly, but give a better fit in the long run. What is the collective wisdom on this?

  5. Lou November 20th, 2007 12:53 pm

    That sounds simply bogus to me. But, if the shoe fits wear it….

    I know this to be somewhat bogus because any good quality liner should not pack out enough to actually mold to a human foot, that is unless it’s close to begin with. My experience proves this to be so. I’ve had a few liners that were too tight, and decided to try and wear them in. Didn’t work.

    More, the Intuition liner can be re-molded numerous times. Thus, if it did happen to “breakdown” then it could just be re-molded.

  6. altis November 20th, 2007 1:34 pm

    Re: footbeds.

    Yes, sticking them to my feet is how Lockwoods (UK) coped with my custom orthotics. Here is how we moulded the Thermoflex liners for my Raichle/Kneissl Flexons last year:

    removed liners from boots an socks from feet
    used double-sided tape to stick footbeds to bare feet
    fitted neoprene caps over toes (ex wet suit bootees ?)
    applied sticky foam pads to pressure points
    fitted very thin sock to hold the lot in place
    cooked liners
    – then, one foot at a time
    wrapped liner over foot making sure the heel was well banged down
    covered the liner in another thin sock
    covered that in a foot-shaped thin plastic bag so that we could…
    slip everything into the shell
    banged heel down hard again
    clipped boot up with moderate tension
    – same with other foot then
    stood up and walked about for 15 minutes

    I’m not sure about the walking about though!

  7. Kevin November 20th, 2007 2:24 pm

    I believe the retailer’s comments would be appropriate for downhill ski boots where they had heat moldable liners that were more a marketing tool, but not comparable to the type of liners used in AT boots.

  8. Rando Swede November 20th, 2007 4:20 pm

    To get the optimum fit I give the customer the option of having the customer ski/skin in the boots a few times. This gives me a starting point for customizing the fit. That way, if a spur/bunion/hammer toe/heel is painful, I can deal with it without wasting one of the re-heats. Normally, I only make extra room for foot irregularities that are painful. The regular molding process forms the liners as needed.

    As for the Scarpa spacing tool… a wooden dowel that equals 1.5 of my stacked fingers has served me well. There’s a homebrew tool for you… But Lou, I’ll bet you’ve go trick inside diameter calipers and a micrometer floating around from your carpentry days!

  9. Shane November 20th, 2007 5:23 pm


    I’ve had 3 different shops here in Bozeman tell me to ride my moldable snowboard boots for 5 or 6 times before trying to mold them. They more or less said that they would fit to my foot better under actual riding conditions with the heat from my foot than they would if I was standing in a store somewhere.

    For the life of me I couldn’t figure out why heat moldable liners even exist if this is the case but didn’t think that such a consensus would exist (how could 3 shops each be lazy?). I plan to ride them a few times then take ’em back for fitting if they prove to be painful.

  10. Lou November 20th, 2007 6:33 pm

    I think it simply works for some people to not mold, if their foot shape is close enough to the last of the boot/liner. Telling people to go try it out first is a good way to save time for the shop employees. If it works it works, but I’m not a big fan of it. Seems like it’s a good way to get at least some people to waste a few days with painful ill-performing footwear.

    BTW all, Scarpa tells me that their “fit stick” is 14 x 30 millimeters.

  11. Stephen November 21st, 2007 6:35 am

    Lou, could you perhaps link the various boot modification articles in the boot fitting section too?

  12. Lou November 21st, 2007 7:27 am

    Stephen, I’ll do what I can. Will probably work on it today and tomorrow, as I’ve got some more boot content coming up.

  13. yyzcanuck November 21st, 2007 9:38 am

    Lou, thanks for posting the article on liner molding and of course thanks for the link to our tech article on how to ‘cook at home’ (http://www.yyzcanuck.com/E_tech_cooking.htm).

    For shell testing we’ve made a stick similar to the Scarpa item you describe. On ours, one end has an 11mm ball and the other end has a 19mm ball. For alpine snowboarding we’ve found this to be the -/+ starting point in shell size that works for most riders but, as you’ve noted, it’s just a starting point.

    In response to Shane & Michael’s experience with retailers telling them to ride before molding. At our shop we mold immediately. This puts 99% of the people on the hill with a good/great fit. The 1%’ers that have a problem come back and we continue to work with them. I figure better to show the benefit of a good moldable liner fit right up front otherwise… what is the point of moldable liners?

  14. Marc November 21st, 2007 10:11 am

    Lou- Do you have any tricks for getting the stink out of well used Intuition liners? I work in my boots all winter and find the closed cell liners are great for warmth and comfort, but not so good for oder! I’ve got a pair that are several seasons old but still going. I recooked them last year, and drove everyone out of the shop with the smell! Recently, I threw them in the wash with hot/warm water (not too hot!) and woollite, but have yet to ski them a day to see if that helped. Any other tips?

  15. Lou November 21st, 2007 12:59 pm

    Yeah, it’s easy. Wash them and then use deodorant foot powder. Wash every few days by just rinsing out then drying overnight with a boot dryer. Speaking of which, after every day you use the boots, use a boot dryer that night.

  16. Josh Hartung November 22nd, 2007 1:41 am


    Your in boot heater method seems very similar the the common stack heaters found in most good boot fitting shops. I am not a big fan of them because they do not completely heat the liner (as with the convection method). This means that the liner will not expand to fill in the various depressions and compress to take up the various bumps common to most shell designs. Instead, it will only compress to take lessen pressure around the foot.

    Commonly I have used these heaters to give a pre-heat to a boot to before trying it on a customer. It makes the boot feel like it would after being skiied for a half hour or so.

    If you are still interested in making one of these heaters, try inverting the boot so the heated air is propelled upward into the boot and is forced to remain there (because hot air rises). Be sure that there is airspace around the cuff so that excess air can escape. This should give you a more even heat.

    Good luck,

  17. Lou November 22nd, 2007 6:48 am

    Thanks Josh, good idea about simply inverting the boot! Why didn’t I think of that !?

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