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Bonding skirt to bubble with Plexus?

KatieB

Well Known Member
I'm at the point where it's time to bond my canopy skirt to the bubble (tip-over canopy, RV-3B). There is no welded hoop on the frame. I bonded 1" strips of .032 around the inside edge of the bubble with ProSeal, and there are 4 anchor points on the frame crosspieces to screw or rivet the bubble to the frame. (Plus the entire perimeter of the glass skirt.) Tony proved the design over 400 flight hours when he built the plane. He ProSealed and pop riveted the bubble to the skirt, then the skirt to the frame.

I'm pondering different ways to do this. Stainless screws would place less pressure on the plexi than rivets. But will my skirt be thick enough to take a countersunk screw head? (the glass, 3 layers of 10 oz., is 1/16" thick on average). Some of my advisors say Yes, others No. I at least want to put screws or rivets where the 4 anchor points are.

Dan the Panther designer suggested I use 3M 5200 marine caulk as a semi-permanent adhesive and sealer between the plexi and the fiberglass, with screws every 4" or so. Next door they build Arion Lightnings and bond their bubble canopy to the fiberglass frame using two-part stinky Plexus adhesive and no mechanical fasteners. They tell me that stuff is indestructable. Sikaflex seems pretty complicated with primers & such. 3M 5200 seems simple and cheaper, single-part and $20/tube. Plexus is simple as well, and available from my buds next door.

Or just do as Tony did with pop rivets and ProSeal... lasted over 400 hours and didn't totally bust apart when it landed on its back.

The other thing is, whatever I use to seal around the top of the skirt needs to be paintable.

I am probably overthinking this, but I've been putzing around with this frame, bubble and custom molded skirt for over a year, so I need to do it right the first time AND get it over with! What do you guys think?
 
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