Square magnetic wire wins praise for tight coils as round wire leaves spaces. In either case the thickness of the wire tends to require multi stranding (2 or 3 in hand) with lighter wire to handle the peak current requirements.
I was thinking about the benefits of square magnet wire maybe found an alternative. You could use strips of copper flashing, wrapped in a single roll at your coil / stator width. Instead of multiple turns per layer, you just have one turn per layer. Flashing is easy to bend, comes in the right thicknesses, isn't too expensive (since it's a building material) and would make perfectly solid coils.
See product example here: LONG link shortened
There were two obvious problems: (1)The flashing wouldn't have insulation and (2) How to connect to the "inside" leg of the coil.
OK here are my solutions: (1) For the insulation you just have to apply some dieletric resin. It's not a simple solution but you can coat one side of the flashing at once. The surface area to be protecting is MUCH smaller than regular wire so you can afford some unevenness or excessive thickness.
(2) Now for getting to that inside leg... You can put two coils side by side, the first wound outside-in and the second inside-out, both in same clockwise direction. Then you can bend the two inside legs towards each at a shallow angle and solder them together across the width of their faces. This leaves you with twices as many turns but both coil legs exposed and no space wasted in bringing a leg out. Alternatively you could drill radially, towards the center and solder a wire to that inside leg. That increases your resistance slightly but is probably easier.
The flat coils can be belt sanded to a perfect even, square shape. The compactness is fantastic and since the face is perpendicular to the flux it shouldn't cause any drag. The two coil method would cut the width in half as seen by and non orthogonal flux paths.
Cutting the flashing into strips might be tedious but I'm sure there is some method easier than tin sheers. I'm thinking a jig and a cutting tool would help. A really nifty way would be to roll a whole 12" wide sheet of flashing into the coil shape and then band-saw off each coil like you are slicing salami.
So what do the wisemen think? Maybe a new product for our sponsor? pre-made coils!