Step 1: Materials
8 dowels - commonly 36 inches long, 1/4 inch is fine for all parts, however I used 1/4 inch for the spreaders and 5/16 inch for the main body of the kite. note - you'll need one extra 1/4 inch if you put wings on your kite.
Twine or string - I happened to have some extra hemp twine around that worked very well but cotton or polyester will work equally well, monofiliment and nylon are to be avoided within the structure of the kite.
2 yards of light fabric - I used some very light rip-stop nylon, but muslin would also work.
You'll aslo need:
scissors, a knife, ruler, needle and thread, and a spool of heavy fishing line.
Step 2: A Knoting Refreasher Before Begining Construction
the constrictor - this is what you'll be binding the frame of the kite together with. try tying this over your finger or a single stick, if done correctly when you remove your finger and pull on the ends the string will pull straight, leaving no knot.
the marlinspike hitch - the constrictor knots need to be pulled very tight and one of the best ways to do that is to tie the loose ends to sticks so you don't have to kill your hands trying to pull directly on the string. like the constrictor this won't leave a knot if the stick is removed.
the artillery loop - this will be used on the bridle, (I'll explain later) it's easy to tie and untie so if you need to change it's position it's quick and easy.
the bowline - this will be the best knot to connect the tow-string (the heavy fishing line) to the bridle. and also the ends of the bridle to the kite.
Step 3: Start Construction
Start by cutting four 1/4 inch sticks in half. An easy way to do this without a saw is to mark where it's to be cut,score it deeply with a knife, then hold the stick with your thumbs close to the cut and slowly rotate your wrists. the ends of the stick should make little circles while the wood breakes where you scored it with the knife.
Now you've got eight small sticks and four long ones. Measure 1/2 an inch from the ends of each long stick and make a mark for the spreaders, also measure 11 and 1/2 inches from each and make another mark for the spreaders. Mark 1/2 an inch from each end on the spreaders themselves.
Tie on the top and bottom spreaders on one set of sticks first, then the other and then slide them together and tie the spreaders together at their centers. Finally tie on the inside spreaders. If you're going to put wings on your box kite, simply substitute a full dowel for one of the inside spreaders.
Once you have your frame set up with the spreaders tied together at their centers and at 90degrees to each other, measure around the outside of the frame, it should be approximately 11 and 1/2 inches between the main frames. Check this measurement yourself as it may vary. Then simply multiply that measurement times 4 and cut out your fabric by that length and 11 inches wide, of course leaving room for a 1/4 inch hem on all sides and 1/2 an inch for the seam where the ends come together. To attach the fabric so as to be easily removed I sewed on strips of cloth at each point that the fabric came in contact with a joint in the frame.
The wings of the kite will be 35 inches (assuming dowles are 36 inches) along the base, and the points 9 inches from the base (double check this when you mock up the frame). Measure from the point the top spreaders meet the frame to the center of the spreader that supports the wings. On the fabric draw a line 35 inches long, from one end mark the distance just measured. then measure 9 inches out from that mark, simply connect this point to the ends of the first line and you have a triangle. Remember to leave room for a hem on all sides. Sew a pocket in the outer point of the wings to accomidate the ends of the spreader. Also sew on strips of cloth at the ends and where the base of the triangle meets the spreader to attach the wings to the frame.
Step 4: Put It All Together
Then begin assembling the frame as you did the first time, but before you tie the top and bottom spreaders together slip the fabric over the frame. then adjust the frame so all the corners line up with the ties on the fabric. Then lash on the inside spreaders and tie the fabric firmly to the frame. The wings are simply tied to the top and bottom corners and the pocket slipped over the ends of their spreaders - remember to sand down the edges of these or they may wear through the pockets.
The only thing left to do is attach the bridle to the kite. Take a peice of heavy twine or heavy fishing line and cut a length that will stand out from the kite about 18 inches, attach the ends to the corners of the frame with a bowline (see step two), then tie an artillery loop 10 or eleven inches down from the top.
Step 5: Go Fly Your Kite
To prepare for flight just use a bowline to connect your line to the loop in the bridle. for the line I used some heavy fishing line.
If the kite has trouble rising or tends to fly more vertical than horizontal try moving the loop in the bridle closer to the top of the kite, but it's suggested that you move in only about an inch at a time.
Also if the kite seems unstable and darts around a lot try making a longer bridle.
for more information on kites and other ideas for construction check out this site: http://www.inquiry.net/outdoor/spring/kites/25kites.htm