Thread: Build Log LightSpeed I repair
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Old Nov 09, 2012, 11:16 PM
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Rick Roberts
United States, MA, Montague
Joined Aug 2012
167 Posts
Rudder and Elevator

The rudder and elevator suffered only slight delamination, but I also fixed a worn alignment hole on the elevator.

In the image, I'm bending the elevator slightly to show the delimitation. The repair was pretty easy. I used West 105 laminating epoxy with 206 hardener and completely soaked the area, then wiped off all excess before applying weight for 17hrs while the epoxy cured. Aradhana gave me detailed instructions for making this kind of repair which after you've done it once seems obvious and intuitive, but I would have never figured this out by myself. In his words:

"I lay the wing on a table, one side at a time, with the side not being bonded hanging out into the air. I use waxed .014 electrical mylar or thin floppy cutting board as a flat, conformable surface. That goes over the repair. On top of that goes a small sandbag (zip lock bags, taped closed work fine) or a shot bag (steel or lead shot, tiny pellets). This spreads out the weight and helps prevent dents. On top of that goes 3-5lbs of weight per square inch of weighted area. Lifting weights, steel bars, jugs of water, what have you.

You wet out the area in laminating epoxy, and then you gently wipe off the excess, all that you get without pressing hard. Don't dent the foam. Then assemble "the sandwich" on top of the repair area."

The elevator attaches to the fuselage with one mounting screw. The second hole in the elevator is for the alignment pin and it became worn and enlarged such that the elevator wiggled slightly. I filled both holes with epoxy and will re-drill them when I'm finished with the repair

For the rudder, the repair was done at the same time and in the same manner as the elevator described above.

LESSON: I completely soaked the hinge side of the elevator and rudder with epoxy, and wiped off all excess epoxy before applying weight and allowing to cure. This worked really well to fix the delamination (I was amazed at how nicely this worked!) but the hinge line also got soaked and when it dried the hinge was stiff. This happened on the aileron too. I tried scraping, filing and sanding along the hinge line to loosen it up, but it's still stiff.

On the second aileron I want to try something different. I will cut a narrow (1/8") piece of blue masking tape and tape the hinge line before applying the epoxy. I'll let you know how that works later...
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