To prepare the Mylars...
Cut the Mylars accurately to the planform at the LE and curved tip.They should be cut a little bit back from the LE -- about 1/16" for a small chord, to 1/8" for a big chord. Extend at least 1/2" behind the TE. The rear edge must be straight across the entire panel.
I feather the 0.014" Mylars for about 3/8" at the LE and tip curve, on the outside surface obviously. This feather allows them to conform to the high curvature at the LE, and it's what allows you to bring the edge of the Mylar within 1/16" to 1/8" of the LE line. The Mylar is quite tough to feather. I use a cylindrical carbide cutting Dremel bit held at a shallow angle against a steel edge, and pass the Mylar edge under it. Sort of a tiny angled planer. Maybe you can devise a better method. Forget sanding -- Mylar is way too tough. Scraping with a razor blade works OK, but it's still a LOT of work. Think power tool.
Tape the top and bottom Mylars together at the rear edge with tape on the inside. I use 1/2" or 3/4" wide clear tape. I'll sometimes fold the seam and put another layer of tape on the outside, wrapped 180 deg around the folded seam. Mark lines for sparcaps, layer edges, etc., on the outside of the Mylars to help alignments during layup. All taping and marking must be done before Freekote application – nothing sticks afterwards.
Clean the hinged Mylars with alcohol, and wipe on Freekote. Paint the Mylars at this point if desired. Matte paint will stick to the wing epoxy much better, and seems to cover better (better light scattering?). Matte paint will of course still be glossy against the Mylar.
All the stuff above can be done well in advance of the layup. After the paint dries, store the Mylars folded to keep them clean.
To cut the glass (also applies to Kevlar)...
I very strongly recommend using a wax paper "carrier" for each piece of glass.
1) Accurately cut all the glass piece patterns out of wax paper. Make the patterns about 1/4" to 1/2" wider than the true chord, with this excess extending behind the TE. Also cut the wax paper patterns for the extra LE strips, usually 1" wide for a 10" chord, maybe 3/4" wide for a 6" chord. I also use a second LE strip about 1/4" narrower than the first.
2) Lay out the glass on a big smooth surface. Lay a big square on it and get the weave threads straight and perpendicular.
3) Lay all the wax paper patterns on the glass, orienting each one accurately at 45 degrees. It's especially important that the two patterns for the top and bottom of a panel are exactly at the same angle and the same orientation on the cloth. i.e. if the warp threads sweep back 45 deg on top, then they must also sweep back on the bottom (not sweep forward!). The latter point is important since glass is never the same in the warp and fill directions. If the orientations between top and bottom don't match, the panel will twist as the epoxy shrinks during long-term cure.
4) Lift off each wax paper piece, turn over, lay on the floor on newspapers, and very lightly fog with a trace of 3M-77. I spray a few feet above the piece, and let the mist settle down. Then place the wax paper piece sticky side down on the glass exactly where it came from. Repeat for each wax paper piece.
5) Cut around the wax pieces. The wax paper prevents the glass from deforming and makes it very easy to handle. If you sprayed the right minimal amount of 3M-77, it might tend to fall off in spots. This is not too much of a problem.
Preparation just before layup...
I strongly suggest using a breather layer which almost completely covers the outside of the Mylars on top and bottom, starting just behind the LE and extending to well behind the Mylar's TE. This breather gives a nice uniform compression over the whole wing even if you have a small leak somewhere. The extension of the breather behind the TE picks up the vacuum-propagating rope or felt strip.
The breather can be cut from a paper towel roll, the fluffier the better. Double-stick this breather sheet to the Mylar to make life easy when things get hectic when closing the bag at the end.
The layup steps are...
1) Spray the narrower LE glass strip with 3M-77 (still on the wax paper), more heavily this time. Stick it to the core, wrapping it around the LE. Remove wax paper carrier. Repeat with the second wider strip.
2) Mix epoxy, and apply very sparingly to Mylar with a narrow paint roller, about 1" to 2" wide is good. You don't need complete coverage at this point.
3) Place the glass/wax-paper accurately onto the wetted Mylar. The front edge of the glass should be very close to the front feathered Mylar edge, but not extend in front of it. Smooth it down and peel off the wax paper. Here's where you find out if you sprayed on too much 3M-77. If it's reluctant to separate, peel it straight back while pressing down on the whole peel line with a metal strip (keeps the glass down).
4) Roll the glass with the roller just enough to wet out all the dry spots. If things look too juicy, blot off excess resin with paper towels and a hard dry roller. Better to apply too little epoxy at first.
5) Wet out the LE strips on the core using the paint roller.
6) Position the core on the bottom Mylar, and fold the top Mylar over.Check to make sure feathered Mylar edges are not too close to the LE. Better to have them too far back than too far forward.
7) Place Mylar/core sandwich in bag, place on top of the bottom foam shuck to set the right twist, and apply vacuum level appropriate for your foam. Only Hi-load-60 and Spyder can take full vacuum. Other foams will crush, so a partial vacuum must be used.
I cure at a somewhat elevated temperature, 100-120F. This is optional, but it does seem to give a better end product, with a better skin/foam bond. Also, if the resin got very thick towards the end, the heating will liquefy it again.
![2F@st4U.:[BE]:.](/data/avatars/m/6/6567.jpg?1429539416){kind=avatar}
) (zie romp is besteld in Duitsland (Nogmaals dank Sietse 
). De vleugel zou zelf gemaakt moeten worden (met de nodige hulp van clubleden)
. 
