Plastic Gummy Worms – Melting Ski Boot Pebax

Post by blogger | December 10, 2008      

Mister Science rides again. I’ve been doing some fit punching on my new pair of Dynafit ZZero. Master bootfitter Mark Rolfes does this by feel and it seems to turn out pretty good, but he does find the Pebax plastic to be trickier than the usual polyurethane of most boots. Since I’ll be doing some of the punching myself, I figured using my trusty infrared thermometer could prevent me from over-heating and thus ruining a pair of expensive boots.

I did some web research and found that Pebax plastic is supplied in different varieties with different melt temperatures. Since I don’t know what variety Dynafit uses for their ski boots, some direct observation was in order. (See menus above for our Glossary, which has more info about Pebax.)

Backcountry Skiing

Pebax after the heat gun.

Above are buckle straps from my older pair of ZZero. Top one in photo was malleable at 200 degrees F, while the bottom one melted at around 300 degrees F. I’ll experiment more today while punching the actual boots, and report back, but it appears that the safe temperature for Dynafit Pebax boot punching is probably just over 200 F.

Another thing I discovered was that my variable temperature heat gun is useful, but the temperatures shown on the settings buttons are way off from what the gun outputs. So, thermometer required.

Know there are different types of Pebax with different optimal molding temperatures. Check this out for info.


Please Enjoy A Few Suggested WildSnow Posts


9 Responses to “Plastic Gummy Worms – Melting Ski Boot Pebax”

  1. Terry December 13th, 2008 7:33 pm

    Great idea with the infrared thermometer, Lou! Do let us know how it goes.

    Am wondering how useful that thermometer would be for snow pits and avy forecasting. was reading about some remote weather stations that use them for recording surface snow temps.

  2. Ron January 27th, 2009 11:05 am


    Just read about your boot heating experiments. How did the punches turn out?
    I ask because I’m about to have my new Radiums punched and I’m looking for a little ressurance.


  3. Lou January 27th, 2009 1:12 pm

    My punched Zzeros are still fine, though when I punched them it did take some of the rocker out of the sole because I got pretty aggressive with the length punch.

  4. Nick Matyas January 14th, 2010 3:45 pm

    It’s an awesome posting.
    It is also very useful for many people like me.
    Your writing is always fabulous.
    Wishing that u will deliver this type of post in future also.


  5. matt November 14th, 2012 7:49 am

    Have well have your punches held up on the pebax boots? I want to get vulcans but seems like the pu version of ‘the one’ is my only option if i want to get an agressive sixth toe punch.

  6. Lou Dawson November 14th, 2012 8:00 am

    Matt, they hold up fine but yes, you can get a better punch in PU boots. Mainly, you’ll be able to punch more distance in the PU. Almost all my heat work is on pebax so I’m used to it, and it always amazes me how much easier it is when I work on the rare pair of PU boots. Lou

  7. Frode November 15th, 2012 4:46 pm

    Hi Lou, just received a pair of dynafit mercurys that seems to be ok in the length, but to tight on the sides of my forefoot/last(even if they say that they are 104,5mm wide on the last). My feet are 102mm wide, measured by bootfitters.

    I am wondering if I could do anything with the grilamid to get a better fit.. do you have any experience with this material?

    btw: I have only tried to mold the original liners in my normal baking oven with fan on blowing into the liners.. I am going to try out the “hot water or hot rice in a bag” molding next, to see if I can get more room around my last.

    There are no bootfitters where I live, so I am left to fix this myself…

  8. Lou Dawson November 15th, 2012 5:16 pm

    If you’re not a boot fitter, you’re not equipped to mold the shell plastic correctly unless you’re quite the do it yourself. As for the liners, go for it. Have you skied or hiked in the boots yet? They should feel a bit tight in width when first molded. Not painful, but tight, so they can pack out a tiny bit in use. Lou

  9. Frode November 16th, 2012 4:14 am

    I have not hiked them.. but they feel painful in these particular areas on boths sides of my forefoots (I am used to thicker alpine liners and alpine boots, so touring liners are new for me).

    I had a new look at my original Mercury liners today, it seems that it is only parts of the liner that contains “moldable material”.. an example will be around the anckle. and therefore the sides of my forefoot will not adjust as an result of molding.. maybe I am wrong? Do you guys have any experience here? I can see that you are always throwing out the original liners and put intuition pro tour liners in your reviews.. maybe this is an good option for me to?

    I am not planning to do anything related to electric heat.. but I am considering to heat the outer sides of my boot with boiling water. But, this will only be an option if I can not mold the liners good..

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