Do Lange (and other) polyether boots require a different approach when trying to gain volume?

[surfandski]

I realize different brands, and even different models within a brand, will use different types of plastics (polyurethane, opaque vs translucent, etc). I understand the opaque polyether in my RS 130 makes it more responsive, snappy and is good at transmitting more feedback to a skier's feet. I've also read comments from boot fitters that the PE can be more challenging to punch compared to other plastics which makes sense if it's more prone to rebounding back like a rubber ball.

This has me curious if most boot fitters alter their technique when dealing with PE boots. Do you prefer to grind these vs other boots? Do you still punch them only using higher temps and for longer periods of time? Do you grind first and then punch so that the thinner material possibly holds a punch better (if that's feasible)?

In my personal experience I first went to a boot fitter who was doing everything he could to stretch and punch my boots but with very little change ever after a couple hours of trying. I then went to a boot fitter who said it's better to grind these boots than it is to punch them do to the material. However, in forums I've read conflicting info from "you can't punch PE plastic because they won't hold a punch" to "you can punch them like any other plastic but you just have to use much higher temps and then keep them stretched overnight for the punch to hold".

I absolutely love my boots and how responsive they are but even though they fit like a glove, I can tell I'll still need the toe box width opened up a bit more when I'm back out in Colorado next year. What I don't know is how much material is left to grind so I'm curious if punching them is an option and if that punch will hold long term or if it will have to be repunched every so often. I say that because I've read several comments from people who had their boots punched and skied them all season only to find that they lost their punch over the summer.

Thanks!

 

[Magi]

The short answer from my recreational reading of the 2016/2017 masterfit university bootfitter's bible is:

TPO (Thermoplastic PolyOlefin) grinds poorly because it is less abrasion resistant than TPU (Thermoplastic PolyUrethane softened with either polyester and/or polyether), so stretching is preferred for TPO boots. Both TPO and TPU can be heat stretched (opacity does not affect this). [summarized from Bootfitter's Bible - Plastic Notes Workshop, page 123-124]


For what it's worth - I ski the RX130, and my bootfitter has expressed no concerns/issues with stretching them.

 

[surfandski]

Thanks Magi. So the polyether holds a punch just as well as the other other plastics? I don't know why that first bootfitter was having such as hard time because he spent a couple hours trying like mad to stretch it but it would just snap back to its original shape.

 

[Tricia]

Sometimes I change the method I use to make room in boots. Quite often the desired results can happen if the process is done slowly.
Some boots are difficult to grind because the plastic gums up.
Some boots don't hold the shape well unless you do it very slowly.
In the RS, I would think that heating it slowly and letting it cool slowly would achieve the desired results.

 

[Philpug]

Thanks Magi. So the polyether holds a punch just as well as the other other plastics? I don't know why that first bootfitter was having such as hard time because he spent a couple hours trying like mad to stretch it but it would just snap back to its original shape.

Usually when the plasic goes back to its original shape is because the heat process was not done correctly, the plastic was not heated to the correct temp and for a long enough time to let the heat resinate into the plastic.

 

[surfandski]

That's what I thought and I even asked the 1st boot fitter if he needed them overnight but he said no you'll walk out with them fitting today (though a couple hours later I still couldn't have skied 1 run in them). He was using a "slot machine" approach where he'd heat up the boots some (I didn't notice the use of a heat gun) and then pull the lever down for 1-2 seconds (like a slot machine) and then release the lever, move it over an inch and repeat the process. This is a good example of why boot fitting is a difficult thing for the average person. On these forums we ask questions to educate ourselves and with enough researching we do learn some stuff but are regularly told on the forums to, "just go to a good boot fitter". I first went to a reputable boot fitter that had all 5 star reviews and he was probably great in most aspects of fitting (including certs on the wall) but didn't appear to have the experience when it came to this particular type of plastic. I'm sure he could have hooked me up if it were an easier to punch plastic.

Thankfully, the 2nd one was awesome and was able to get me really close by grinding but I think I will still need to gain a little more volume in the forefoot and I'm not sure there is enough material in there to continue grinding so hopefully he will do some stretching when I'm back out in Colorado next winter. I got to the point where I could stay in the boots for half the day as long as unbuckled the lower buckles for the ride up but even then, my forefoot/instep were being squeezed just enough that my feet almost felt cold even though it was way above freezing out. The boots were no longer like a neanderthal squeezing my hand to where it went numb but more like someone still giving a firm handshake where circulation was effected. I thinking doubling the room we gained with the grinding should have them fitting like a nice, tight glove.

I'm sure professional boot fitters get tired of answering questions on these forums but it really does help us at least understand if what the person is doing seems right or not. I would never try to tell a pro how to do it but it was frustrating to sit there and watch the 1st boot fitter stretch and release the boot when I had researched enough to "at least think I knew" that they 1. needed to be heated more and 2. the punch needed to be held for more than 1-2 seconds.

Forums like this one are so valuable for us!

 

[cem]

the key to stretching any plastic shell is heat and pressure the correct amount of heat and then the stretch is easy, too little it springs back, too much it fries...with the PE that Lange uses the key is taking a longer time to heat the shell, i like to use a lower temp and heat for longer to get the temperature all the way through the plastic (same with all boots but the lange takes a little more effort) i also where possible use a press with a steel head, this way i can blast the metal of the head with the heat gun and get heat to the inside of the shell as well, i find this gives the best results. the boot and press then go in the freezer (our customers travel distance to get to us so keeping the boot overnight is generally not an option so we have a chest freezer to chill the boots after stretching.)

as for grinding compared to stretching a boot, it is a personal choice and depends on how much space is needed, there is certainly 2-3mm (if not more)of material that can be removed form the sides of a boot like that in the forefoot so if that is what is needed then i may grind rather than stretch, but if i need a space for a big bunion or protrusion then the press is the most efficient method..... Race boots on the other hand we grind a lot as the plastic is much thicker

hope that makes sense