I had a few pallets lying around and wanted to create a chair, and that's exactly what I did. So, I built this Just For Me Adirondack Style Chair from two pallets, about four hours, and without any plans at all. I created it exactly the way I wanted, to fit me. :) Hopefully, the pictures I supplied will help you build your own!
Just For Me Adirondack Style Chair Frame:
First, I used two stringer boards as the main supports. I cut angles on one end, and mounted the other ends to a deck board. I used Gorilla Glue and screws to hold all the joints together. Next, I used two more deck boards to create the front legs and mounted them to the support frame I just made. Note the angle that I installed the main support frame. This will let the seat and seat back be at a comfortable seating angle. Next, I added a cross-piece between the two main support stringer boards. This stabilized the legs and gave me a place to mount the seat boards too. Finally, I cut two triangular pieces from the scrap stringer boards and mounted them to the outside of the front legs. These pieces provide additional support and a place to mount the armrests too.
Just For Me Adirondack Style Chair Upper Assembly:
I alternated wide and thin strips that I cut at about 1.5" wide, leaving small gaps between the boards in case of rain. I used a 1x6" stringer board, cut into two pieces and trimmed down towards the back for the armrests. Temporarily, I used some boards to prop the armrests up while I installed the backrest support piece. I used more of the stringer board to create the backrest support piece and mounted the rear armrests to it with screws and glue. Then, I installed the backrest slats, alternating wide and narrow boards to match the seat pattern. I angled the top the way I liked, sanded everything to prevent splinters, and put the chair on my deck. Finally, I applied a light stain and sealer to the chair.