21. Rohacell-31 is cut to size and placed on top. Rohacell-31is a polymethacrylimide foam made by Evonik in Germany. It is something like foam polystyrene but stiffer, and not affected by diesel fuel. If it is unobtainable, a polyurethane foam could be substituted.
22. The Rohacell is vacuum bagged down and allowed to cure. 6 hrs at 40 degrees.
23. Bag is removed. 3mm is trimmed from the leading edge and tips.
24. 3mm is trimmed from around the edges. At the bellcrank a 10mm diamond is also cut and filed.
25. Micro balloons, Q-cells and epoxy are mixed until they are stiff. This mix is then applied around the edges and at the bellcrank centre. This cures for another 6 hours at 40 degs.
Enlarged view
26. Micro balloons and epoxy cured.
27. The wing is sanded flat with a 5" flap disc on my milling machine by sliding the mould by hand underneath. The bed is raised until the carbon skin is reached.
28. Take care to remove dust beneath the aluminium while sanding.
29. Leadouts grooves are marked and cut.... Unfortunately was in the wrong side of the wing. Not the first time I have done this.
30. Tool for cutting the grooves. Hacksaw blade attached to a aluminium block.
