This is going to be a very quick, very sparse general tutorial to a lot of questions I've gotten about the long fall boots for my Portal 2 Chell cosplay.
Basically they are welded steel. Eight pieces per boot to be exact. I got some pictures of the process, they're not the most helpful but if there's enough of a want for it I'll post some sort of tutorial. Though it seems a little pointless since so far all the personal messages I've gotten, the process couldn't be used by those asking. D:
I found a boot, I chopped up the boots, mainly the toe and the front part and sides. With my brother's help, together we welded a u-shaped frame for my upper calf. From this we had straight pieces going down either side of my calf (inner and outter) and then hooking around the bottom with more pieces of metal. This provided a hook around my heel that would support my weight much like a high heel shoe. Then we hammered out the shape of the 'spring' on two separate pieces of metal, one fitting inside the other. Those two pieces were welded together and then this was attached to the back of the u-shape around my calf. The boots sit inside of this frame and we cut up a tire and glued the treads onto the bottom of the metal 'spring' to provide a more stable and safe surface for walking that would keep me from slipping and killing myself. The white details were layers of wonderflex we shaped and heated and attached to the metal frame.
The boots support my weight which is in at about 125 lbs. After days of walking and rough housing on them one of the supports snapped and had to be re-welded. If you weigh over 130 I would suggest looking into carbon fiber, which I have zero knowledge of. Seriously.
The boots can be made, but without the proper knowledge of welding, working with steel, and safety equipment I'd rather y'all not hurt yourselves. D: Please. I have the burn marks and scars from the boots. They are less than perfect, but they got the job done. Like I said even with reinforced metal on the springs, the two pieces snapped apart at one point. The metal also rubbed my ankles raw and another time the velcro took skin off the front of my calf. Live and learn.
There is also the matter of safely walking in the boots. I'm still not sure how to describe it. It's a strange feeling, and also not exactly the safest mode of transport, or comfortable. I'm sure there are better ways to make the boots but these are what I did, and so if you too want to go the welding route just lemme know. I'll help as best I can.