> Flex notches reduce the life of the boot. This is a big deal for me because I crease boots really fast.
...Any explanation or comparative results provided? Seems odd to me. I thought the flex notches would reduce local stress and prolong the life of the boot. I've considered flex notches as an example of an advancement in boot design arising from a flash of insight, easy to implement without complex technology.
It's possible that boot makers don't test everything they "know", but base some of their advise on what they believe to be general principles. Even a very experienced expert can be wrong.
But consider one possibility: when you relief that stress, created by bending the boot, with the flex notch, the boot can bend more. Maybe adhesive-stiffened-leather (which, as near as I can tell, is stiffened by making it more difficult for leather fibers to slide against each other, though I might have that wrong - I am basing it on what I have read, that you oil leather to make it more flexible, by letting the fibers slide against each other more easily), and the other stiffening structures inside the boot, can only bend more so many times without starting to break down.
As a rough analogy, if you were to look at a weight bearing bridge, and were to take away the part of the structure that supports most of the weight, the bridge might collapse. Also, if you bend it too often and too much, the adhesion between the leather fibers, both natural and adhesive enhanced, should break down, and the stiffened leather should lose its compression resistance, and a crease can develop. That applies to tension structures, like a suspension bridge too - you don't necessarily make them stronger by removing the strands that hold most of the tension. At least I don't think so, though I'm not an engineer.
Think of it like a resin-stiffened fiberglass (or other resin-stiffened-fiber composite) ultralight boat or ultralight aircraft. You need the adhesion to block the material's natural flexibility, as well as to provide resistance to compression. (Ultralight boats and ultralight aircraft are made stiff and strong without much weight by balancing a tensile resistant element against a compression resistant element. Such a cool idea! Of course, they do eventually break down, but there are big advantages to lightweight craft.) if some of the resin breaks down from excess flexing (as it eventually does on composite whitewater kayaks, though BTW, polyethylene has largely replaced composites on consumer market boats, because it is more resilient), the structure of the boat or aircraft is likely to crack.
I believe an inward crease is caused by compressive pressure when a foot bend pushes the boot to bend. If you can convert compression of that part of the boot by tension, by filling the presumed point of empty space or reduced outward pressure, it can't bend inwards, and no inward crease can form - or at least it will take a lot more time.
So, it seems to me that, for the most part, an inward crease such as Bill's pictures show, can only occur if there is insufficient outwards pressure from the foot there, because of a poor 3D fit. A heat mold could in theory alleviate that poor fit to some extent, though if you do too many heat molds on the same boot, that will obviously eventually beak down the leather. I have also sometimes applied adhesive foam inside the boot, to equalize the outwards pressure from the foot to the boot, and eliminate the local low pressure point - i.e., applying tension to the leather, by applying outwards pressure to force it to stretch. I believe I have slowed down and even partially revered nascent creases in such a fashion.
But it is difficult to know any of this for certain, unless one is willing to run a large scale experiment, using many skaters, a lot of skating time, and destroying many boots in the process.
So any such speculation could be completely wrong.
It is also possible that there are more variables that affect whether flex notches reduce or extend lifetime. E.g., it is no longer the case that all figure skates are largely composed of adhesive-stiffened-leather. Maybe composition affects what makes the most sense. It's easy to oversimplify.
Topic: My visit to the new Harlick Factory (Read 3906 times)