Note from Bob Kuykendall
A long time ago, Dick Schreder told me about a novel method for holding wing skins onto the ribs during the gluing process. He said that you can use a shop-vac connected to the interior of the wing to create enough of a pressure differential between the inside and outside of the wing to hold the skin right down on the ribs while the EA9430 epoxy sets. He also warned that:
- You must make sure that the ribs are properly sanded, and the leading edge curve fits tight. Vacuum fitting the skins helps get the skin evenly bonded to the ribs, but is no substitute for good workmanship and attention to detail.
- You must plumb the vacuum lines so that vacuum is applied both ahead of the spar and behind the spar.
- You must make sure that all of the wing ribs are properly notched for drainage, and that all interstitials are ice-picked, as specified in the plans.
- You must carefully regulate the vacuum so that the ribs just barely show through. He said that he used a capped chunk of PVC pipe with a bunch of holes drilled in it for a regulator - he just taped over more and more holes until the vacuum was right.
- You should do this with all of the skins fitted, and all seams taped over. However, you’re still just gluing one skin at a time; the other skins are just there for containment.