Scale ribs
I milled a mold reproducing the rib structure with a CNC
pantograph, from a 10 mm thick nylon sheet. I then
drilled a 10mm hole at each intersection of the
structure. I made then a sort of extractor screwing on a
piece of chipboard some 6mm screws, having hexagonal
head, so to match the holes on the nylon
templates.
To build the rib I inserted lists (3x3 or 4x4 mm in
accordance to scale) the cut outs, top and bottom are
linden or spruce wood, obeche or hard balsa for the cross
braces, and for the front of the rib I used poplar
plywood cut on the pantograph.
The whole thing is pushed all the way down precisely into
the template, then I dripped some drops of CA on each
intersection of the structure, using also the 10mm holes
so to add some CA drop from the bottom
After few minutes
I layed the template on the extractor and by hammering
the nylon slightly the rib came out of the template
perfectly glued.
The addition of
0,6mm birch plywood plates has even overstrengthened the
whole part.
The weight of each rib is almost the same of the rib made
in lightened poplar plywood but with a far superior
strength.
Some suggestion