Bill:

Sorry, I did not see your question (post 426). Regarding glueing the sheets together, yes I was going to suggest taping the sheets together, then turn them over, apply glue to the joints. Once this is done, lay the shins on a flat surface (taped side down), wipe away any excess glue, place wax paper over the skins, place appropriate size piece of wood over the entire skin and then place weights (don't need a lot, perhaps 30 lbs evenly distributed) on them and let dry. When dry, the side that was taped becomes the side that I put on the outside. However, I use a "T" bar sander to sand both sides to try to ensre there are no ridges where the glue joints are. I ahve found that using an aliphatic resin works very well (Elmers glue or the "original" tite bond of Sig's white glue). The new Tite Bond II or 3 or some of the newer Elmers glue and gorilla glue are polyurethane and this as well as CA make a glue joint that is harder that the surrounding wood. If you use a CA or polyurethane for a glue then you will end up sanding the surrounding wood down and have a ridge where the glue joint is.

Duane:
There are a couple of sources for laminating resin. Z Poxy laminating resin is one but West Systems and System Three also make laminating resins. Personally, I have used System Three (www.systemthree.com) for about the last 10 years and about 25 builds. System Three (as does West System) have a full range of epoxies. I do not have any experience with West but I am sure they are just fine products. System Three have a structural epoxy called T-88 that I use for firewalls, landing gear plates and other high stress areas. They have a general epoxy that has a common resin and your choice of three different hardeners (each with a different cure time) and finally, they have a laminating resin called Clear Coat. the Clear Coat is mixed two parts resin to one part hardener. It has the consistency of Aero Gloss clear dope or very close. I use the clear coat to attach wing skins as well as to apply fiberglass cloth to the wing skins.

I agree with others that there are multiple approaches to grain orientation for wing skins. Long ago, I was taught that the grain for the skins should be parallel to the leading edge and to the trailing edge. What I do is to determine the rough widths required for the wing skins at the root and tip. I then run one sheet parallel to the leading edge and one parallel to the trailing edge. Once these are positioned, I then fill in the "triangular" shaped remainder with sheets to fill the balance of the skin. On my latest Black Magic VF 3 i glued a number of skins together (sufficient to make on top and bottom skin for a wing panel) and then cut it diagonally to make two skins for one wing panel. When I did this, I had the grain running parallel to the trailing edge of the wing and that left the graing running at an angle to the leading edge. I have to confess that I much prefer the grain running parallel to the leading and trailing edge. I have attached three photos. One photo is of my 2meter scratch built plane and if yo look at the wing you will notice the grain runs parallel to the trailing and leading edges (not the best photo but the only one I had that was close); one photo of my stab on the new Black Magic VF3 where the grain is parallel to the trailing edge but at an angle to the leading edge. The third photo is a better shot of this approach and is of the fuse on the Black MAgic (look at the vertical tail). I have found that if the grain runs parallel to the trailing and leading edges, it conforms to the radius of the foam much better and I get better results.

As for glueing wing skins to the foam cores, I again use the System Three clear coat (if you choose to use System Three clear cost DO NOT thin it). The amount I mix depends on the size of the wing panel. Most of my wings are about 450 sq. in. per panel (about 17' chord at root, 10" at tip and about 34" long). For skins for this size wing I mix about 30 -40 grams of glue. First thing I do is to apply two or three coats of balasrite to seal most of the wood and keep it from absorbing a lot of epoxy (this adds about 10 grams to a wing skin). I spread it evenly along the entire skin (always apply the epoxy to the balsa and never to the foam) using an inexpensive paint brush (the 1.5" wide units form Lowes for about $1 each works well) ensuring I get epoxy on all of the balsa. Once this is done I use an old credit card and gently squegee about 1/2 of the glue off. I then apply the skin to the foam core, set it in the shucks and then apply weights to the shucks. I went to Lowes and bought two pieces of 2 ft. x 4 ft. x 3/4" thick MDF. I put one piece of the MDF on the floor (need to find a very flat surface on the garage floor or some other place) On top of this piece of mDF I place the foam wing core with skins and the top and bottom shucks and then place the second piece of MDF on top of the wing. Once this is done I start to add weight continually checking to ensure that the foam wing core is still in alignment with the leading and trailing edge of the shucks as well as having the root and tip lined up with the end of the shucks. I use the "cinder blocks" from Lowes or Home Depot. If the wings are not honeycombed then I put about 250-300 lbs on the wings. This drives the shins into to contact with the foam. I once applied about 350-375 lbs of weight to a wing and when it came time to separate the shucks from the balsa skins, I had applied too much weight and managed to force some of the epoxy thru the grain of the balsa skins and glue the skins to the foam shucks, not good). If the wings are honeycombed, then you need to put less weight on the wings (perhaps 150 lbs). Honeycombed wings will crush with too much weight or if bagging too much vacuum.

I know this was a long winded reply and I hope I understodd the discussion about the direction of grain on sheeting wings and approach to skinning foam wings. If I misunderstood, I apologize.

Ed