Fairing in a canopy step?

[rmartingt]

Getting ready to start laying up canopy skirts as soon as today or tomorrow (RV-7 slider), but thinking ahead just a bit to the fairing over the windscreen... I sika'ed the plexi but goofed in one spot and forgot a spacer on the RH side of the windscreen, a few inches above the longeron. The end result is a positive step of about 1/8" from the windscreen to the canopy on that side.

My thinking here was to do the initial layup, then add some micro as a filler to smooth the transition and try to hide it, and finish with a last single ply over top of it to "protect" the micro.

Does this sound like a reasonable approach? Is the last ply necessary? Should I use another filler?

I was also thinking I'd finish the fairing and skirts off the aircraft and then sika them on.

[DanH]

Originally Posted by rmartingt

My thinking here was to do the initial layup, then add some micro as a filler to smooth the transition and try to hide it, and finish with a last single ply over top of it to "protect" the micro.

Does this sound like a reasonable approach? Is the last ply necessary? Should I use another filler?

Micro isn't fragile, and doesn't need protection. That said, a ply overlay is fine, and may actually be useful if the application includes a sharp edge.

Got to ask...why not just cut the sika and correct the fundamental problem? Others may not notice an asymmetrical canopy fairing, but it will bug you forever.

I was also thinking I'd finish the fairing and skirts off the aircraft and then sika them on.

Makes sense. No point in epoxy bonding a fairing to airframe and plexiglass, when the plexiglass is floating on sika.

[wirejock]

If I understand, the windshield is 1/8" narrower at one side?
I would get the skirt trim done first, then the windshield trim Then if there is any gaps, fill them before primer and paint. Doing it that way allowed me to fab the wimdshield trim with a pocket that the skirt slips into.

Dan's method of cutting the sika would make it perfect but it may require cutting the sika and removing the windshield. You need to get the spacer and sika in the correct place. I had a similar but elected not to remove and replace the windshield.

The windshield moved before the sika set. It created a high spot. I covered it with some creative fiberglass trim. I know where it is, but I doubt very many people would find it. Maybe the Airventure Judges!

[rmartingt]

Originally Posted by DanH

Got to ask...why not just cut the sika and correct the fundamental problem? Others may not notice an asymmetrical canopy fairing, but it will bug you forever.

I'd be more afraid of damaging the canopy trying to cut that section loose. Looking at it a minute ago I think I can hide it fairly well if I bring the fairing up to the edge of the sika line on the inside. It won't be the biggest cosmetic goof I've made anyway.

Originally Posted by wirejock

If I understand, the windshield is 1/8" narrower at one side?
I would get the skirt trim done first, then the windshield trim Then if there is any gaps, fill them before primer and paint. Doing it that way allowed me to fab the wimdshield trim with a pocket that the skirt slips into.

Yes, that's the plan (skirts first). I haven't messed with fiberglass since making Dad's intersection fairings 20 years ago so this is going to be a new learning curve...

[rmartingt]

Skirts came out ok-ish, for a first time I guess. Good tight fit to the aircraft, but the (one piece} assembly needs some filling work to get smooth.

Question is, should I final trim the edges, glue/rivet* it on, and then do the finish fill work? Or do that first and then attach?

It's not the stiffest thing when it's loose, but I think I'd get a better final finish doing it on the canopy frame when it's in final shape and referenced to the aircraft (though it would take a lot of care to protect things while sanding).

FInishing off the canopy means no risk to the plexiglass but I'm worried it might get cracks or runs in the process.

Temporarily attaching for finishing sounds worst, as the clecos would be in the way.

Suggetions?

* Sika all around, plus blind rivets into the frame and solids into the holey stiffener piece

[wirejock]

Finish cosmetically till you think it's ready for paint then Sika it with clekos. Minor repair to fill the holes, prime and paint.