(ed note: reformatted John’s original text to be easier to follow for those needing to do a repair themselves)
I’m in the process of repairing a fuse that was damaged just ahead of the wing saddle. I thought one of you might like to look over the fence at how I’ve gone about the repair.
- I used vinyl tape to frame the repair area well ahead of the damage.
- Next, I used Norton Fine 150 grit to take the repair down to the Kevlar.
- I cut a section of carbon fiber and satin [ed: nylon rip-stop or satin: acts as a breather layer and doesn’t stick to the epoxy] wide enough to cover the repair area and extend over ½ of the vinyl tape front and aft.
- I mixed a small batch of West System epoxy resin and hardener.
- I mixed the two at a ratio of 1 to 5 parts. (3 grams hardener to 15 grams resin)
- I used a ¾ inch artist brush to coat the repair area.
- With rubber gloves on I wrapped the area with the carbon fiber working out the wrinkles as I went along.
- Next, I wrapped the satin patch over the top of the carbon fiber, again working out the wrinkles.
- Next, I wrapped the satin patch with a paper towel cut to fit the repair area.
- All the wraps only extended halfway over the vinyl tape. The vinyl tape is used to frame the repair area and give you a nice straight edge to work with.
- Moving right along, I used vinyl electrical tape, stretched tightly, wrapping the layers of carbon, satin, and paper towel, compressing the patch while squeezing the West System through the carbon fiber and satin into the paper towel.
- The next day I unwrapped the patch and was pleased to see a very tight repair without wrinkles or bulges.
- I used several new razor blades to trim the carbon fiber at the edge of the vinyl tape while lifting the vinyl tape off the fuse. It was a tedious process to clean up around the patched area, but can be done with good results.
- Next, I used Low Oder Mineral Spirits to clean the area of any and all signs of vinyl tape residue. The edges of the carbon fiber and the carbon fiber itself were not as smooth as you can get them. Back to West System for the solution.
- This time I mixed a smaller batch (2 grams hardener to 10 grams resin) with West System Microlight Fairing Filler added and mixed to the consistency of creamy peanut butter.
- Again, I used an artist brush to coat the entire patch extending ¾ of an inch ahead and behind the repair.
- I let this dry for 24 hours before sanding it with a coarse sandpaper that quickly shapes the repair.
- Finally, I used the Norton fine 150 grit sandpaper to smooth the rough sanded area.
Please find attached two photos that show the repair before I start the final finish process.
The [continuing] mission is to “purty” up my Supra. Yesterday, I spent my time with primer and 320 grit wet/dry sandpaper. I coated the patch area and aft section with Krylon Flat White primer, lightly sanding after each coat. I simply wanted to fill any sanding scratches that may have been left over from the previous work. The smoother you get this task, the smoother and more light-reflective the final coat will be. Late into the evening, I figured I’d made it an average “purty.” Next, I applied three light (very light coats) of Krylon White Gloss from the nose to the boom. I went to bed with visions of grandeur and a flying machine that can dance with the Eagles on silver clouds.
Hope you’re looking over the fence cause I’ve got a real “purty” machine to show you. I used an airbrush to trim out the Fluorescent Green stripes followed by three light protective coats of clear gloss. I’ll let the whole thing harden over the next few days while getting my teeth worked on and a fun day at the field Friday. I hope to see you there. When I get back to this project, I’ll show you how to build a high intensity LED strobe controlled by one of the switches on my TX. In the event, my plane goes down on a faraway soybean field turning the strobe on should make the plane easier to find after the sun goes down. The strobe is very, very bright. I’m anxious to see how bright it will be, at altitude.