Begin by preparing the kite’s sail. Trim off the self-adhesive ﬂap from the ﬁrst envelope. Cut the folded seam along one 13" edge and the 10" edge. Lay the envelope ﬂat to create a roughly 20" by 13" rectangle (see image).
Lay out the envelopes as shown in the image. If you want your kite to advertise the fine services of FedEx, UPS, or United Postal Service Priority Mail, then position the envelopes with the corporate logos facing up. If you prefer a white kite, turn the plain sides up. You can decorate your kite using permanent markers. Because Tyvek takes ink really well but packing tape does not, this is the time to decorate the kite if you are going to draw a design.
Use strips of packing tape to join the rectangles into one large sheet, and then set aside the large sheet. Trim one of the two bamboo stakes to 33" (leave the other at its full 4' length). Cross the two stakes, or spars, as shown in the image, so that the short cross bar is centered and 15" from the tip of the long spar, and then tie a snippet of string around this intersection. (This is optional, but it makes it easier to maneuver the spars; the string keeps them more-or-less aligned for the next step.)
Lay out the large Tyvek sheet so that the packing tape is facing away from you and the extra bit of Tyvek is in the upper-right corner and jutting off to the right. Place the spars on top of the sheet, as shown in the image above. Use long strips of packing tape to attach the frame directly to the sail; be sure to leave 2" at the end of each spar untaped.
To reinforce the edge, tie the string to the end of any spar, and then run the string to the next adjacent spar, looping it several times around the spar and overlapping the string on itself (as shown in the image). Run the string from spar to spar until you are back at the start. These lines should be taut without deforming the kite (which should be a symmetrical diamond); you can adjust them for maximum tension and symmetry. The combination of the almost untearable Tyvek sail, the flexible bamboo frame, and the fluid reinforcement of the string will cause the wind to bend the kite into something similar to an Eddy bow kite—a remarkably stable and easy-to-launch design. Eddy bows are the gold standard in simple recreational kites. This kite has the advantages of the Eddy bow without your having to invest a lot of time in tailoring a neatly curved sail.
Use long strips of tape to secure the string around the edges of the sail. A taut sail will spill air evenly off its edges and will be more stable in flight, so be sure to keep the sail as taut as possible. (Realize that you are taping envelopes to string; it’s not going to be taut as a drum head.) Leave a 1/2" section of the bottom of the long spar clear of tape. After the string is taped down, cut away the excess sail, leaving a 1/2" margin around the entire diamond, as shown in the image. (This margin might be a little rough, but don’t sweat it.)
Snip off the margin at each vertex of the diamond sail (seen in the image) to create four flaps along the edges (similar to the envelope flaps you removed in Step 1) that you can fold over the string along the kite’s edges. Fold each flap over the string, creasing it as close as possible to the string reinforcement. (You can run the side of a marker down these creases to make them nice and sharp.) Tape the flaps down. Now you’ll add the bridle. Flip the kite over so that the exposed spars are underneath, measure 10" from the top and the bottom of the long spar, and mark these points on the face of the kite. Use the tip of the utility knife, scissors, or a nail to poke holes through the sail on either side of the long spar.
Cut a 44" length of string for the bridle. (I don’t advise using kite string; heavier string will hold up better, especially if you’re omitting the 1/2" split ring.) Feed one end through the top set of holes, tie it to the spar, and then feed the other end to the bottom set of holes and tie it to the spar. (Optional) You can add the bridle ring now (see “Adding the Bridle Ring” on page 289 of "Snip, Burn, Solder, Shred") or wait until your first kite-flying excursion.
Now for the tail, which adds stability by dragging down the bottom of the kite and shifting the center of the kite’s weight toward the bottom of the diamond. (Think of a canoe, which is most stable when the weight is close to the bottom; stand up, and the boat gets very shaky.) A 9' caution tape tail might be overkill, but it looks pretty, even in a crash (especially if you get caught in a bad crosswind and start looping). You can trim it down or add to it at your discretion. To connect the tail, make a 1 1/2" cut into one end of the strip of caution tape. Then tie it around the open section at the bottom of the long spar, as shown in the image above. (If you don’t have caution tape, you can tie together a few narrow newspaper bags or even use strips cut from a garbage bag. Since this plastic is so lightweight, you’ll need to use a full 9' or more to stabilize your kite, depending on conditions. You can maximize the length of such a bag tail — and thus the drag it exerts — by splitting the bags along both long edges before tying them together.)