January 24, 2015 - Plywood Backing Strips
I needed 16 plywood backing strips, two for each spar ladder, plus another two for the lower wing spar ladders.
January 24, 2015 - Plywood Backing Strips |
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| Before I could glue the spar ladders and spacers together, I had to take care of the spar bolt holes. There was more to this than I had realized. The first thing I had to do was make plywood backing strips for the outer spar bolt holes. These plywood backing strips would go on the inside of the spar ladders. Their purpose was to counter the spar ladder taper, making them "square" for the spar bolts. To do that, these plywood backing strips themselves needed to be tapered. How do I do that? No problem, just use my scarfing - sanding drum technique. I did, and it worked great. | ||||||
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I needed 16 plywood backing strips, two for each spar ladder, plus another two for the lower wing spar ladders.
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| Fitting the plywood backing strip to the spar ladder. The tapered edge faces inboard. I used my new electronic micrometer -- bought at Harbor Freight -- to make sure the distance was uniform across the spar ladder outer edge and the backing strip inner edge. Then I epoxied the plywood backing strip to the inside of the spar ladder. I used the little brass nails on each corner to hold the backing strip tight while the epoxy dried. | ||||||
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