Or attempting to restore a melt down from last year.
Molded Balsa Stressed Skin Monocoque Fuselage.
Foam blocks are laminated to center line profile cut out of handy piece of paneling..
Couple of formers to guide shaping of foam. Shaped with 40 then 80grit. When close to shape stroke in one direction only to avoid peeling/tearing of foam.
Couple coats of minwax polyurethane(oil base) and then a couple coats of kit car wax.
4-6 hours to make plug.off and on day for minwax and next day wax.
The Skin is 2 layers of 1/16th around 5lb cf Balsa from Lone Star.
Edges of sheets are fitted and joined flat, rough cut over size.
First(inner) layer the grain is aligned with of fuselage(form) bottom center line and pined to the center line.
outer side of skin is whetted with paper towel, worked around form and overlapped, wrapped with masking tape and left to dry over night.
Trim to fit at overlap.(on top)
Tape seam tight, slide off of form and super glue seam.
Slid it back on form
Second(outer) skin is done same with the inner skin in place on the form WITH OUT laminating!
For the outer skin the grain centered with the TOP of form center line.
In this case the grain bias or ply measured out to around 20deg.
The bias to the grain stops grain spiting from torsion loading and results in a high strength in torsion as well as locking shape in place(cross sections)
Now trim over lap of outer skin (on bottom)and leave about 1/8th inch gap.
Thin down Tight Bond Aliphatic resin with water.
Make sure inner skin is in place on form.
Paint the Aliphatic resin resin on to outside of inner skin.
Keep a water mister handy in case it try's to thicken while the coat is evened out and dry spots tended to to get even thin coat. Also the balsa is going to absorb some amount so 2 coats might be needed.
I wound up applying to much and then wiping excess off with paper towel.
GLUE IS WEIGHT!
Make sure the resin is wet and quickly slip outer skin into place.
Work any 'slack' into the bottom 1/8th inch gap area.
Wrap with tape(ace bandage works good also)and let dry overnight.
This fuselage is tapered so it can be slid off the rear.
For other simply split inner skin through 1/8th gap and then remove and re glue.
Fit a strip of balsa to gap and glue.
IF skins stick to mold(it will) long,rounded and smooth strip of around .032 aluminum slid betewwn form and skin
very gently. just where it will go with out excess force.
Compressed air gently blown between skins and form will do most of the rest.
Rubbing and gentle pushing on skin will do the rest.
Weight upon removing from form was right at 3oz.
After a few days of drying this dropped to something under 2 ounces.(1.5 is what I seem to remember.)
1 former at the front of cockpit/T.E. of wing
Fire wall at the front, no other formers.
There is 2 vertical grained pieces(1/16th) placed inside below Stab for load transfer.