Best Filler for side skirt gap?

I am building a 7A Tipup and am finalizing the canopy frame. The problem I am having is the gap between the fuselage and the canopy frame (WD-725), once I put the side skirts on. The gap is uneven and at some points is as large as 6/32. I thought about aluminum shims to take up that gap, but am concerned with unsightly bends when I rivet. I am considering using some sort of filler to build up that area and sand to a good contour. Anyone use any filler in this location? What did you use? Bondo? Epoxy, carbosil, flox mixture? Fiberglass reinforced epoxy? Aluminum re-inforced filler, or just leave it and worry about it at paint time? Any suggestions would be grreatly appreciated. Thanks.

The right side of my tip-up had a gap problem, but it may have been different than yours. The R side canopy skin and frame ran inside the fuselage line. IOW, if you looked down from above the canopy, there as a 1/8" showing of the fuselage top rail from frt to back, but worst at the fore-aft mid-way point. I made up shims of .025 and match drilled them to the canopy skin, and then varied the layers of shims (behind the side skin) depending on the "gap". It was two thicknesses at the center point, tapering to one at the fore and aft ends. I then used slightly longer rivets. It ended up a perfect solution ... there's no way to tell today that side is shimmed.

canopy frames

rmr said:

I am building a 7A Tipup and am finalizing the canopy frame. The problem I am having is the gap between the fuselage and the canopy frame (WD-725), once I put the side skirts on. The gap is uneven and at some points is as large as 6/32. I thought about aluminum shims to take up that gap, but am concerned with unsightly bends when I rivet. I am considering using some sort of filler to build up that area and sand to a good contour. Anyone use any filler in this location? What did you use? Bondo? Epoxy, carbosil, flox mixture? Fiberglass reinforced epoxy? Aluminum re-inforced filler, or just leave it and worry about it at paint time? Any suggestions would be grreatly appreciated. Thanks.

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You don't have to accept the canopy frames as they come out of the box. They are not all perfect. you can bend and massage the frames somewhat to fit the contour of the fuselage. A good fit of the frame makes it a lot easier to install the side skirts. You should not have to use any shims or fiberglass in this installation. In my installation, I actually made new side skirts and front skin so that it overlapped the fuselage by about 3/4 of an inch. This eliminated that ugly crack between the canopy and fuselage. Just my 2 cents.

Thank you for your suggestions.
The WD-725 do not follow the curvature of the fuselage perfectly on one side and although i tried to bend them it looks like a job better suited for a metal shrinker than brute force. I will try the shims and see. Once again thank you for your replies.

C613 skins

I had a problem with the QB fusledge I got from Vans. The F721 I believe it is top rails were suppose to be even with the fusledge skins but in some places were in almost a 1/16 and other stuck over the side skins by a 32.

so after reading that the side skins were to sit onthe skins I trimmed the F721 rail full length to allow my C613 side skins to rest on the fusledge skins. This was pretty difficult as it required a slightly wider C613 which i had to re order. If I had not cut the origional one down to Van's dimensions i would have been fine.
The nice benefit of all this was an extremely tight fit on the C613 to fusledge skins. There are pictures on my web site probably in the second log and about 400 in the pictures.

I also had to add a stop to the rear of the canopy frame since I do not rest on the F721 side rails I did not want all the weight on C613 and the skins.
Take a look... it is an option if you have not cut the C613's to width yet.

Smilin' Jack