General Cover Questions

[jmorrical]

Starting to cover the wings. I have seen various fillers used in places like the extended cargo door. The transition from the first and second leading edge skins ended with a 3/64 inch gap in one place. Will tape and fabric mask the small gap? Or would I need to take the time to feather it out with a filler.

5F82D418-B84D-4D76-B7B6-DBAC528E74CC.jpeg

[TroyBranch]

Make sure the thickness is not larger that the strut attachment. If it slides on fine with the fabric plus paint, no issue with fabric there.

There were clear cautions to glue these areas well with Poly-Tak as fabric was put down. Now that I’m heading to paint soon how much fabric on the strut attach and stabilizer brace wire fitting and should I cut back? Or none?

Attachment 10878

Attachment 10879

[TroyBranch]

I put chafing tape there before I covered. No filler.

Starting to cover the wings. I have seen various fillers used in places like the extended cargo door. The transition from the first and second leading edge skins ended with a 3/64 inch gap in one place. Will tape and fabric mask the small gap? Or would I need to take the time to feather it out with a filler.

5F82D418-B84D-4D76-B7B6-DBAC528E74CC.jpeg

[Mark Keneston]

Starting to cover the wings. I have seen various fillers used in places like the extended cargo door. The transition from the first and second leading edge skins ended with a 3/64 inch gap in one place. Will tape and fabric mask the small gap? Or would I need to take the time to feather it out with a filler.

5F82D418-B84D-4D76-B7B6-DBAC528E74CC.jpeg

jim. That’s a gap but you should be able to take 1” wide chafe tape and run it the full length of that seem. Do it to all of the over laps. When you do the shrink on the fabric, this likely pulls in. Also cover the tops and bottoms of the tail ribs that are not full ribs. These end at a sharp point. Any hi points need to be checked. Also run your fingers over anything that touches fabric. Welding spray slag and other slag that can punch holes in fabric. You want the finish to be smooth and nice Thanks MK

[jmorrical]

From page 20 the Poly Fiber manual: 'Two coats of Poly-Brush (on the leading edges before cover) should provide a 'bedding' that will help adhesion and reduce the possibility of pinholes in the finish coat.' I have seen one mention of that here on the forum, but mostly no one mentions it. Should I do that?

chNhEtm2TO6xWuhw+1amTQ.jpg


Here in SE Texas lately it's 97*F with 60%+ humidity by 2PM. I have been working in mornings mostly, but I have a question about using Poly-Tak in these conditions. Would I be better off to pre-glue the concave aileron and flap bays then activate it with MEK for better control and to get a good glue fit / finish. The Poly Tak dries so fast here. I want to avoid botching this area up.

zTuTObfDS4uzw%Nu3AQl3A.jpg

[Daveembry]

Jim. Extensive coverage of this on my wing cover videos on the Carbon Cub EX Builders Facebook group.

From page 20 the Poly Fiber manual: 'Two coats of Poly-Brush (on the leading edges before cover) should provide a 'bedding' that will help adhesion and reduce the possibility of pinholes in the finish coat.' I have seen one mention of that here on the forum, but mostly no one mentions it. Should I do that?

chNhEtm2TO6xWuhw+1amTQ.jpg


Here in SE Texas lately it's 97*F with 60%+ humidity by 2PM. I have been working in mornings mostly, but I have a question about using Poly-Tak in these conditions. Would I be better off to pre-glue the concave aileron and flap bays then activate it with MEK for better control and to get a good glue fit / finish. The Poly Tak dries so fast here. I want to avoid botching this area up.

zTuTObfDS4uzw%Nu3AQl3A.jpg

[kevestes]

Jim,

Thanks for posting both of these points. I am at the exact same stage you are and had the same questions. I opted for Dave's latest method of working across the aileron cove horizontally since he's built four planes and I've built zero but had to do it in very small steps as I was having the same challenge of 95 degree heat and the polytak was working faster than I was. As Dave mentioned in his video I too wasn't 100% happy with the end result but plan to tidy things up when I flip the wing on the horses.

In regards to precoating the leading edge with polybrush, I talked to Polyfiber and they recommended at as it almost guarantees you won't have pinholes because it penetrates the fabric from both sides. I then talked to Cubcrafters and they said not to do it because they thought it might interfere with the shrinking process. It's another one of those conundrums as whose advice to follow. I did determine that the polybrush barely adheres to the shiny surface of the leading edge and you can pull it back off in one big sheet. I am still not sure which method to use but will need to make that decision today.

From page 20 the Poly Fiber manual: 'Two coats of Poly-Brush (on the leading edges before cover) should provide a 'bedding' that will help adhesion and reduce the possibility of pinholes in the finish coat.' I have seen one mention of that here on the forum, but mostly no one mentions it. Should I do that?

chNhEtm2TO6xWuhw+1amTQ.jpg


Here in SE Texas lately it's 97*F with 60%+ humidity by 2PM. I have been working in mornings mostly, but I have a question about using Poly-Tak in these conditions. Would I be better off to pre-glue the concave aileron and flap bays then activate it with MEK for better control and to get a good glue fit / finish. The Poly Tak dries so fast here. I want to avoid botching this area up.

zTuTObfDS4uzw%Nu3AQl3A.jpg

[kevestes]

Jim,

Thanks for posting both of these points. I am at the exact same stage you are and had the same questions. I opted for Dave's latest method of working across the aileron cove horizontally since he's built four planes and I've built zero but had to do it in very small steps as I was having the same challenge of 95 degree heat and the polytak was working faster than I was. As Dave mentioned in his video I too wasn't 100% happy with the end result but plan to tidy things up when I flip the wing on the horses.

In regards to precoating the leading edge with polybrush, I talked to Polyfiber and they recommended at as it almost guarantees you won't have pinholes because it penetrates the fabric from both sides. I then talked to Cubcrafters and they said not to do it because they thought it might interfere with the shrinking process. It's another one of those conundrums as whose advice to follow. I did determine that the polybrush barely adheres to the shiny surface of the leading edge and you can pull it back off in one big sheet. I am still not sure which method to use but will need to make that decision today.

From page 20 the Poly Fiber manual: 'Two coats of Poly-Brush (on the leading edges before cover) should provide a 'bedding' that will help adhesion and reduce the possibility of pinholes in the finish coat.' I have seen one mention of that here on the forum, but mostly no one mentions it. Should I do that?

chNhEtm2TO6xWuhw+1amTQ.jpg


Here in SE Texas lately it's 97*F with 60%+ humidity by 2PM. I have been working in mornings mostly, but I have a question about using Poly-Tak in these conditions. Would I be better off to pre-glue the concave aileron and flap bays then activate it with MEK for better control and to get a good glue fit / finish. The Poly Tak dries so fast here. I want to avoid botching this area up.

zTuTObfDS4uzw%Nu3AQl3A.jpg

[jmorrical]

Covering wings of my EX with extended fuel, wig-wag lights and Executive Glass G3X. It is not an EX2 or 3 that most of you are working. I have seen Dave Embry's edited figures knowing it's for an EX3.

It's clear my Cover Manual has figures showing errors in inspection grommet positioning. Trying to make sense of it all from several figures and sources considering the differences with extended fuel, wig-wag lights and G3X panel wings.

I'm not sure about inspection grommets at the drag wire fittings near the extended fuel bays. Do I add one at both the forward and aft spars so fuel tanks could be removed some time if necessary? Can't find dimensional info for those.


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[E.V.]

Jim if you get this call 256-310-3806 or email at evroosevelt210@gmail.com
EV