Making a Custom Gap Seal Part 1




I was not impressed with the quality of the fiberglass nose cone from Quad City for the money it costs. The factory gap seals also struck me as pretty pricey so I determined to make my own, at least for the front and middle pieces. Also, I planned to mount my com antenna on the front gap seal; so since I knew I'd have to modify the factory part anyhow, I made my own. This photo shows the windshield covered with thin polyethylene, an arch of aluminum flashing former spanning the door frame tubes, and strips of flashing taped to the front of the former. Adjust all parts till they fit the way you'd like. Duct tape works fine to hold them in place. Be sure to leave enough clearance under the form for the flaperon mechanism, ballistic chute bridle, and any other connectors you may be planning in that area. I honestly didn't have all that stuff in mind and I was just lucky is all fit after the piece was made.







Reinforcing cloth is then draped over the former and wrinkles smoothed out. The cloth should extend well beyond the edges of the piece you're making. This is a material called Dynel. I used it instead of glass cloth because it's softer, friendlier to work with, drapes well around curves and corners, and doesn't shed glass slivers to cut and irritate your skin. It does cure with a slightly rougher texture than glass cloth so there's slightly more surface work to do for smoothing and fairing. But for me, the trade off is worth the small additional hassle. It's available from Defender Industries and other marine supply outlets.



Brush the resin of your choice into the cloth being sure to saturate it thoroughly. I used epoxy for maximum strength and flexibility since the piece was going to be thin. Areas of cloth that are resin-starved will show up a lighter color; these areas and any bubbles will be obvious as the fabric becomes transparent when it's fully saturated. Be careful not to push more resin through the fabric than it can hold. Besides making a mess from drips and wasting resin, it could make getting the piece off the form more difficult. Before the resin starts to set up, make sure the cloth is draped smoothly across your form. Pay particular attention to corners and curved surfaces. Once the resin starts to kick, don't mess with it any more. If you discover a flaw at this point, let it cure and fix it later.







After the resin is fully cured, you can line off easily from the structure visible through the translucent laminate. Then lift the piece off the airframe and remove any pieces of the form that are adhered to it. The aluminum flashing is so smooth that it peels off easily as long as excess resin didn't flow under it and seal it into the piece. Resin doesn't seem to stick to duct tape either. Aviation snips work fine for trimming. Also visible in the photo is a mock-up of the leading edge of the wing made of styrofoam and pvc pipe. This will be used to shape the trailing edge of the gap seal. The trailing edge is left untrimmed at this point. For the next steps, go to part 2.








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