CHAPTER 68 – Fiberglass 101
Well, I already mentioned the wing tips. Due to those strobe blisters, it’s time to finally start working with that ‘other’ material. Fortunately, I have a friend who’s building a Lancair and is willing to help. For the record, his system (which he credits with Lancair) beats the heck out of how I used to do this on model and full-size sailplanes. Hopefully I won’t get in trouble for telling their method.
The first step is pretty straight forward, just like metalwork. Position, drill, and cleco the tips to the wing. I used a straightedge to make sure the top of the tips were even with the wing laterally. Rough trim was done with an old set of snips and finer trim was done with sandpaper and file. Each wing took about half an hour. Then the blisters were positioned. I had drawn a centerline down the strobe attachment and simply leveled this line with the main longeron. I made sure the flat surface was vertical (the plane being leveled laterally), and that it matched the aft part of the tip for fore/aft alignment. This was easy; I’m sure I only fussed on each one for a couple of hours. Ok, sarcasm aside, once I was happy with their position, it only took a couple of minutes to drill and cleco them. I used #40 in case I wanted to adjust slightly. Big mistakes are easier, just redrill and fill the extra holes later.
Now for another fairly easy part. The fourth picture shows the blisters being glued on. I used Hysol (the blue stuff) to glue the backing plates into the blisters and then normal resin to glue the blisters onto the tips. The clecos are dredged in paste wax to keep them from sticking while they hold the parts together. While I was at it, I used some Hysol to glue the rudder bottom fairing together; the clamp is holding it to the contour of the skin. When it was cured, I glued the backing plate for the tail position light to the assembly using more Hysol and also filled the gap around the light bulge. In the next couple of pictures you can see the parts rough sanded and waiting a layer of glass tape to fair the joints.
First I cut my tapes, all of them, to the length I’d need for the layups. We then laid them out on pieces of blue plastic and mixed up the resin. After pouring on a reasonable amount on each piece of tape, we laid more blued plastic on top. After the tape had soaked up resin for a minute, we used a hard roller (made from a length of drilled bolt) to push excess resin around to dry spots and generally make the tape evenly impregnated; excess resin was finally pushed off to the side. A sharp circular cutter was then used to cut the plastic closely around each tape, leaving the wetted tape sandwiched between dry plastic.
The actual layup was very easy and not very messy (still use gloves, though). The bottom layer of plastic was peeled away and the exposed tape was laid into position. Then the top layer of plastic was removed and a brush used to remove all air bubbles, make minor position changes, and be sure all the edges were down. Once all the layups on a piece were made, they were covered with peel ply to soak up excess resin and give the cured surface an ‘edge’ to better take priming and filling. Once cured, the peel ply is ripped off and the pieces are basically finished. I’ve carefully fitted the lights and done some rough shaping as necessary but I’ll leave the final filling and finishing for the paint shop. The last thing was to go back and replace the tips on the wings, using #6 screws and nutplates.