Here are a couple of great tricks aiding in kite construction. Both of these methods temporarily secure the sail to the building surface so parts can be accurately and neatly installed.
The first technique (among many) was shown to me by a true kite god and good friend, Brian Johnsen. When using non-porous synthetic sail materials, i.e. plastic sheets - Mylar etc. one encounters unique handling problems. Sliding around, rippling and static are three of the biggies. The following remedy makes uncooperative synthetics very manageable.
The tools necessary are: A sheet of glass large enough to contain the kite, an atomizer, a squeegy, glass cleaner, a scraper and some paper towels. I cut sails on a thick sheet of Teflon using a half template and an X-acto knife. The cut sail is then transferred to the glass sheet. To prepare the glass sheet building surface, clean throughly. Spritz the surface with a little water from the atomizer and lay the sail front side down. Sprits a little water on the back of the sail and dampen the blade of the squeegy. Stroke the squeegy over the sail until it lays down flat. Some excess water may ooze from under the edges of the sail. The sail will suck down to the glass sheet flatter than a crepe`. So flat that any foreign objects left under the sail will become annoyingly obvious. Gently dab the moisture from the back of the sail with a paper towel. Remove moisture from the unused portion of the glass also. Depending on the seal, the sail will stick to the glass plenty long enough to add parts. I've seen them stay put for weeks.
If the material chosen for the sail is flimsy and difficult to cut accurately, try this. Employing a half template, cut the sail out directly on the glass surface. To do this, squeegy half of the sail material down to the glass, fold in two and re-squeegy. Cut the sail out, unfold and re-squeegy to the surface. Using a whole template, squeegy the material directly on the glass surface and cut.
The second trick was developed by yours truly. It is similar in that the sail material is fixed to a surface for ease of handling but with materials that are less conducive to the previous technique. When using paper, silk, Orcon, Tyvec and the like for sails, I like to tape the material to the construction surface.
The tools necessary are: drafting tape. Drafting tape appears very much like masking tape but differs in that the amount of adhesive is less. It is less sticky allowing a temporary fixture. Again, I cut sails on a thick sheet of Teflon using a half template and an X-acto knife. Whether the sail is transferred to another surface matters less here. Cut six pieces of drafting tape 1 and 1/2" inches long. Fold a small amount of one end of the tape over - sticking it to itself. This will make a tab to grab a hold of when it comes time for removal. Set the tapes aside for easy access. Spread the sail on the working surface front side down. Tape the nose of the sail to the working surface. Insure the tape is straight and centered over the spine line. The tab end of the tape should be facing the middle of the sail. Do the same on the tail end. A slight amount of tension on the sail is O.K. This may create two small furrows of ripple on either side of the center line but worry not. Add two more tapes to the nose. One on either side of the center tape, tab towards the middle of the sail. Do the same on the tail end. Now the sail should be stuck down with three pieces of tape on either end. Carefully remove the center tapes. Now we have four pieces of tape securing the sail to the working surface, nice and straight with a little tension down the center line. The center line is now free of tape allowing room for the spine. Set the spine. I like glue the spine on and tape the ends down using permanent tapes. Remove the temporary tapes. The permanent tapes will continue to secure the sail to the working surface. Use drafting tape to secure the wingtips. Use the hand to brush out ripples. The spine will help to insure the wingtips are square to the center line. Tape down the wingtips in an area that will not interfere with bow installation. If there are permanent leading or trailing edge tapes to be installed, it might be necessary to move the temporary wingtip tapes around.
Always experiment with tape before executing construction. You won't want any accidents. Drafting tape is available at art supply stores. You can make the stuff from masking tape by rolling the sticky side on cotton or flannel to suit. Drag it across a pair of Levi's and try it out on scraps.