BOOTFITTING PART 2: MODIFY THE OUTER SHELL
Within Boot Fitting techniques you can include all the techniques ranging from lengthening or shortening of the hull plastics to thermoforming, to adding custom insoles or volume changes. The possibilities of modifying the boot are many and depend on the will (or need) of the user and the skill of the technician.
One of the techniques for working on a boot is to modify the outer shell (the plastics hull), especially when it comes to width problems such as pain complaints in the ankle bone or lumps on big/small toes, heels, etc.
It’s quite normal that a customer can’t indicate exactly where the pain complaints are; “The ankle bone is not in the place where the boot hinges. A good way to determine the exact problem is to start with the inner shoe. Draw lines of the problem area(s) point with a marker, chalk, or even lipstick. By putting back the inner shoe into the outer shell of the boot, the marked lines/area(s) will easily show precisely which issues need adjustments or modifications. Working with magnets is another technique that can be used to address these problem areas.
You can also mark the foot, then step right into the outer shell of the boot with your inner sole (leave out the inner shell) and get marks on the outer shell, due to the pressure of the marked foot. Putting pressure on the outer shell in order to extend this. Hull machining: milling and lengthening of ski boot hulls, thermal widening of pressure points, to relieve discomfort or thermoperforation of hulls and shoes.
Extending the outer shell can be done in multiple ways; “There are all kinds of beautiful tools that a boot fitter can use to extend the outer shell, make it wider or fix lumps. A wooden or metal last is often used in order to make the right and precise adjustments. Putting pressure on the outer shell, with a cork/foam or metal adjustable attachment makes it possible to give or relieve pressure. Thereafter the plastics hull is heated via heating stacks, infra-red, or a hot air blow dryer.
HEAT IT UP
The process of heating of the shell must be done slowly, using the right temperature (NOT extremely HOT). It’s specifically important that mainly the outer shell is heated before molding and shaping it. If the outer shell is heated too quickly and too hot, the plastic can bubble or melt. When properly heated the last will do the trick, adjusting the shell into its desired shape.
This often looks pretty extreme when everything is expressed to the desired width, but once the shoe has cooled down and the adjusted lasts are removed you will see the shoe bounce back a bit and most likely offer a big improvement.
On some occasions, another technique is used:” The customer steps into a heated outer shell while wearing the inner shell, covered with foam”. This technique is a more natural way in order to create natural adjustments. Important during this process, when using the way of molding and shaping, is that both the shells and the boot are fixated, to prevent twisting the boot.
Molding the outer shell usually ends up giving a solid result. Be aware of the fact that all the plastic materials, of both the outer and inner shell, are indeed able to be molded. Cheaper boots (incl. the shells) have different layering and plastic constructions than a more high-end boot.
It’s important to prevent the upper cuff (both the shaft and the flap) to collapse when widening the boot. Especially with hiking boots, due to the fact, these boots don’t have a separate shaft and flap, over even an overlap. Be cautious, otherwise, you will go from bad to worse.
The use of carbon parts in boots is becoming more regular, especially for hiking boots. These boots are more difficult to mold and shape due to the usages of carbon. Therefore a professional boot fitter will be a bit more reluctant to adjust these types of boots.
The cooling down process, while molding the shell is key and most critical in the entire boot fitting process. Normally this takes quite some time, even up to a couple of hours before the shells are completely cold. If you are already done after 10 minutes, chances are the whole process of boot fitting didn’t help much. Plastic naturally returns to its original shape, so it is important that the shoes can cool down for a longer time, with the adjusted attachments, and lasts in it.
Fortunately, the outside temperature is a lot lower in the winter months, meaning that all the modified elements of the boot can even cool down more perfectly. A thermo-shock in a freezer is another option as well as letting the elements cool down in cold running water.
The usage of cooling pads or snow is a common way to – if available of course. The only problem with using snow; ”Snow melts faster than your boot will cool down”. So, just make sure to take as much time as possible for your boots to cool down before using them! If your adjusted boots return to their original shape, the boots either have not been heated enough or cooled down long enough.
Next time, BOOT FITTING PART III: “The inner shoe of the Boot! Standard OR Custom-Made”?
More info: www.bootzimmer.com