Custom Alpine Boot Fitting – Part 2
Hi, this is Todd from Mountainside Ski Service in Warren, Vermont. We’ve done the assessment on the athlete to find a boot that’s going to work for them. Now we’re going to go ahead and build a footbed. We’re going to do the casting, we’re going to do the posting up, and we’re going to bring the material down to fit within the dimensions of the boot selection.
What we’re going to try to do is address that arch issue being a spring, and the evolution that produced – let me see your foot for a second – that produced this arch to act as a spring when you’re laden. I really want to stop that, because as the foot elongates, and your toes spread under athletic activity, I need to stop that so that the boot fits consistently under all loads – whether you’re sitting on a chairlift, or whether you pound it down from a mogul.
In order to do that, I’m going to create an impression of you on a rigid piece of material that’s going to suspend and stall that ability for that sprint to flex. How we’re going to do it, is we’re going to set a cast of your foot with the shape of your arch and the width of your forefoot. We’re going to use a thermoplastic blank – I’ll show you one that’s not been heated – a thermoplastic blank that I’m going to heat up, slip under your foot, put your foot back, and we’re going to make a reverse impression of your foot on laden.
Here I have a cooked up blank. It’s nice and flexible. Go ahead and pull your foot right up out of here. I’m going to set this blank right back in here. This is going to become your footbed. This material here will be shaped down to the size of your ski boot. You just stay put. I’m just going to pack the material in around you. Because of your muscle out here, I’m just going to remove the material so it doesn’t cup up in any way. I’m just going to leave you. Sit for a second and let it cool.
That will begin the process of making a footbed. Once the blank is cooled, I’ll then post it on a material to give you a nice, stable platform underneath because it will me rounded and cupped. Then I’ll shape this down to exactly the same diameter and dimensions width-wise of your ski boot. If we go too wide, it will act like a canoe and add too much pressure on this part of your foot, so I need it perfectly flat from this point to this point. Couple things going to come of that: 1) We’re going to suspend the spring action of your foot. 2) I’m going to give you a leverage bar on the ski between these two points.
That constant flexing, reverse camber in your foot can really make it tired. By stopping that, many folks find that their feet are no longer tired, and just overall comfort in the boot is cranked up. Ski boots are different than every other boot that you put on. It is a fixed foot sport, which means that I’m looking to suspend all the evolution of forefoot expansion and that arch being a spring. As you get active on your feet, this is what your arch does. I want to suspend all that. In order to do that, I’m going to build something underneath it. That’s the whole purpose behind a footbed – to suspend evolution.
That’s it. Go ahead and pull right up and out.
Amy: That was excellent. Excellent analogy.
Todd: This one, perfect.
Amy: Ahh, beautiful.
Todd: This one, I’m going to let it sit there for a minute.
I’m going to take this newly formed blank that was made for Amy. I’m going to cite the location of her first and fifth metatarsal head in the center of her heel. To do that, I’m simply going to run this back and forth across the bench and then slide this back and forth across the bench to scuff up a little bit those points.
These contact points are going to be the controlling factor inside the boot. When I’m done posting this, from here to here will be one straight, flush plane. Then next step is to build the post self. This is done by citing these on here, cutting them to size. This is for a 23.5 boot. I need to cut this down to 23.5. Nice, straight line. Then I’m going to cite these two things to be a nice, straight line.
The technique I use to make sure I get a line back up is I’ll score it with a Sharpie just to give me a couple of target lines on that so that when I put it back together, I’m looking to line that stuff up – same thing with the heel.
Those are my target lines once I get done gluing it. The next step in the process is to apply some adhesive to both materials: the posting material and the blank itself. This is a little thick, but it will do. I’m going to coat this nice and evenly, starting behind that line.
There’s no sense gluing in front of it, nothing’s going to be glued up there. Make myself a nice, buttery mess on the bottom of this to glue this whole thing together. There’s the back of the blank. This is the part that’s going to touch the foot. Then I’m going to take this piece, which I cut and marked, and I’m going to do the same thing.
I’m going to butter the inside of it. The beauty of contact cement is once it’s dried and you touch these two surfaces together, it will hold like a weld. I just want to make sure I get all this material saturated with it. I’m simply going to let it dry off. I don’t want to put them together until this material is pretty much dry.
We’re going to pick up where we left off. Got a casted blank shaped for Amy’s foot. We’ve trimmed down the posting material. We’ve marked where we’re going to lay it up. Now I’m going to use these two target marks to just line up the bow of this thing. Then I’m going to cite the heel over this hole.
Todd: Now I’m just going to adhere this posting material to the blank all the way around, and make sure we’re making good contact all the way through – down through the center, all through the arch, and across this forefoot between the first and fifth metatarsal head. Anywhere where I feel I can’t get a good bound, I’m just going to put a little bit of pressure on it and roll it right out.
Once I have that done, let’s just remove this excess. This is the general shape of the now posted blank. The next step in our process is to remove all the material that is too big to fit in Amy’s boot. We’ll show you the method I use to score and size these things.
The next part of this is to take this obviously larger than the interior of this boot and bring it down to size. In order to do that, I’m going to remove the bladder, and I’m going to remove the factory footbed that comes in it. You can see that there’s very little, if any, arch to that. Considerable difference when we’re done. This is the dimension that I’m looking to shape.
I’m going to set this down and I’m going to take everything away – including that line. This will bring it down dimensionally to what the inside of that boot is going to accommodate. This is just the first roughing. The final fitting will come when I set this trim down into the inner boot and make sure it doesn’t exceed the boundaries of the inner boot. As you can see, right now it clearly does.
My next step in the process is going to be to grind down all this excess material – including this scribe line – to fit the inner dimension of the boot. Once I’ve got that done, I’m going to go ahead and site and shape my plane from first to fifth metatarsal head and heel, so all that’s one plane. As I get busy doing this, I’m going to make a bunch of noise and a bunch of dust.