Before assembling the rack, I laid out the spacing for the line at 1-inch intervals along both edges of one side panel, and transferred the layout to the second panel, as well as to the center support strips. At each layout location, I cut a 1/4-inch-deep kerf with my Japanese hand saw to hold the line (1). When all the parts were ready, I screwed the rack together using deck screws. I held the spreaders about 1/2inch in from the edges of the side panels so they wouldn't interfere with the fishing line.
Running the fishing line around the rack was easy but slow going. I anchored the line to a screw driven into the side near the bottom, and fed it outside the edges of the side panels and inside the center support strips. After slotting the line into the kerfs on four corners to create one "shelf," I led the line up diagonally to the next level and went around again. The challenge was feeding the line and making it tight enough to support the shingles without sagging, but not so tight that it pulled the sides in. When the first spool of line ran out, I drove a screw into the side panel at that level and tied off the loose end to it, and used it to attach the new line.
The screw also gave me a place where I could adjust the tension in the line. After I'd strung the entire rack, though, I found the line needed to be tighter, so a friend helped me slide a 1x4 board behind the line along one of the sides, which gave me the extra tension I needed.
Once the rack was assembled, I was ready to stain the shingles. I set up my work table next to the rack (4). Using a roller—the fastest way to apply the stain—I coated all the sides and edges of each shingle.
I loaded the rack from the bottom up so I could see the fishing line as I slipped the shingles in. The rack held three boxes of shingles or about one square, which I could stain in a couple of hours.
When the rack was full, I decided that it would be best and cleanest to store and transport the shingles in their original boxes. I came up with a quick, easy way to put them back. First I measured the width of the shingle box and marked that measurement on my table, subtracting 1/2 inch for clearance. I then sorted the stained shingles into three sizes.
I then sorted the stained shingles into three sizes. Using the marks on the table, I stacked rows of shingles, taking the appropriate sizes from the sorted piles and alternating the butts on each row to keep the stack straight and square.