Those grid fins are nuts! Are they wood squares with a bunch of holes burned through them?
Somehow I'm imagining those snapping off upon landing rather frequently.
Nyt,
Yes, I'm concerned about how strong these pieces are. The fins themselves are some kind of thin plywood that is laser-cut even with all the holes. They are strong enough. It is the struts, which are CA reinforced cardboard that is the worry. Early on, before I hardly started, I thought maybe I could just fold them up on the side.
The instructions say to paint the inter-stage struts with 20-minute epoxy using a disposable acid brush. So, I did that today. The devcon epoxy package stated that the cure time is 30 minutes, but it was shorter than that. Half way through operation I started a new brush and then I used a toothpick and a wooden skewer to pick out epoxy clumps and wipe them on a 3x5 index card. I think that thing turned out reasonably well.