Framing for the solar kiln began with a truckload of 2x4s of various lengths as called out in the VT plans. The first wall I built was the front or south wall. Nothing fancy, just normal framing 16" on center. One minor change I made from the VT plans was to utilize a three stud corner instead of the specified four stud corner. The three stud corner allows just a little bit more insulation in the corner to help decrease some of the heat loss through the studs.
North wall framing began by constructing the built up beam that will serve as the door header. Two 2x8s, some of the 1/2" plywood offcuts, and about a billion nails completed the beam. The north wall was framed while laying flat on the kiln floor. Since this was a one man operation, I added some additional, temporary studs to the outer edges for the lift. It was easiest to use the south wall as stop and use the truck to slowly raise the wall. Once it was vertical two support studs were nailed to each side. These studs allowed me to slowly "walk" the wall back one side at a time, little by little without the fear that it would tumble down north or south. I would just lift up the support on the north side, drag one end of the wall a foot or so towards the north and let the south support drag the ground. Go to the other end and do the same thing. Repeat, repeat, repeat...... When the wall was flush with the north edge of the floor, it was nailed in place and a temporarily attached to the north wall.
No special framing was done on the south wall to help with insulation. I figured I would need plenty of studs to hold the beam and hold the door hinges.
With the south wall and north wall complete, the two side walls were next. Some 45 degree cuts on the top were about the most complex part of the side wall framing. It was a good time to think about the stud placement relative to the outer edges of the north and south walls. Locate the side wall studs so the edge of a full sheet of sheathing can fall on the center of a stud. The second sheet can then be cut to fit. This helps keep down the number of cuts on the sheathing. Assuming the north and south wall are parallel and plumb, it made it easy to build the side walls laying flat on the floor between the north and south walls.
The roof framing is made up of 2x4s at 24 inches on center. This framing was a bit more challenging as it required more angle cuts.
Lessons Learned - I should have added one more bit of blocking toward the north end of each end wall. The 4x8 sheathing (interior and exterior) nearest the north wall does not reach the top of the kiln. A small triangular filler piece is required. It would've been nice to have a horizontal block in place for additional nailing where the full sheet of sheathing meets the small filler piece.