Scott Cable has sold this very nice KR. There are some very good ideas contained in the information that he sent me over the time that he was still building it. He gave me another CD along with narrative, at the 2004 Gathering and I have placed that information on his page.
Thank You Scott and Michelle Cable
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My turtledeck is constructed using foam to create the shape, the laying up an outerskin. After the outer skin was cured, I removed it, and carved 4 Hat Stiffeners into each "frame" location, and also longitudinally along the centerline. I used a router ( 3 passes each hat), and then created a sanding block tool that was the final shape of the hat. I then laid Duct tape down into each of the hat cavities, then used heavy 8 mil plastic and traced the hat trims onto the plastic. I then cut 3 inch BID tape to length, and squeegied West System epoxy into the BID. I then transferred the lay-up onto the Foam tool, and relieved the plies wherever the cross former layups crossed BL 0.0 hat. Then laid the BL 0.0 down relieving the layup wherever it was crossed also. I then mixed up some cotton flox, and placed a 1/2 inch wide CF "flange" along the perimeter of each Hat. Prior to doing any of the lay-ups, I prepped the outerskin, by marking on the outside where the duct tape was laid. I then used 60 grit paper to prep and break the glaze of the underside where it would bond with the hats. I then wiped it clean with Acetone. After the perimeter of flox was done, I placed the outer skin down over the hats, and placed bungee cords at each hat location. I then allowed the whole turtledeck to cure.
Several hours later, I checked the excess resin in the mixing cup, and checked the remaining CF. Both were
rock hard. I then popped the co-cured / co-bonded hat stiffened turtledeck off of the foam "plug". I'm excited that the results are nothing short of fantastic! There is no foam that remains with the completed part, is extremely stiff, and yet very lightweight. I then popped the foam off of the airframe and took the whole thing downstairs for final cure (at least 24 hours).
Things I learned during this process:
1.) The Frost King Window film makes an excellent release film. It's readily available, and inexpensive. Works well with complex curvature.
2.) I really, really like the West System for laminating. Wets out very well, stable working time and doesn't have a horrible odor. (still wear your mask and gloves).
3.) Hat stiffeners offer a great deal of stiffness, at a fraction of weight.
4.) Laying down Duct Tape for a release ply takes a great deal of time to do properly. Take your time, and work in small sections. I resorted to the duct tape for the hats, did several tests of with the Window film in the hat cavitys, each one failed. Too complex a shape for the window film to "shrink" into.
5.) Everywhere Cotton flox had been laid, were little "blisters" of epoxy working it's way through the outer skin. Proving that I had good bonding of the hat stiffeners to the outer skin.