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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: schrocketeer on December 14, 2018, 02:51:45 PM
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To square up a crack in my RT fairing, I used a piece of wood and some sheetrock screws to make a splint. My Nurse wife told me the medical phrase for that is an, "external fixator".
After the splint was in place on the outside, I applied Bondo fiberglass jelly on the inside of the crack.
My plan is to sand down this first layer, then add some fiberglass cloth, then more jelly, to strengthen the repair.
Since I'm already going to re-paint, filling and painting the holes left from the screws will not be that much more work.
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Nice idea using the splint to hold things in alignment. I just finished doing some crack repair on my RT fairing. The cracks went from just behind the mirrors down and were the result of a couple slow speed parking lot drops.
One thing I have learned the hard way recently recently is that polyester resin is not the way to go when repairing the bulk molding compound the fairing parts on these bikes is made of. It turns out that the resin for the original part is compounded with mold release mixed in, and as a result the release agent cannot be removed before a repair is made because it goes all the way through the part.
Polyester and vinylester resins don't bond well over time to bulk compound parts because of the release agent. Epoxy on the other hand loses no adhesion so the repair bonds to the part much better. I found this out the hard way when a previous repair peeled off of the fairing in a minor drop.
It's a pain in the ass working with epoxy because it cures so damn slow, but the strength is much better.
Another thing I do now is to prime a repair with cyanoacrilate glue(super glue) before using filler. I haven't had too much trouble with polyester fillers cracking out, but a little extra caution shouldn't hurt.
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Nice external fixation, your brick must have very good health insurance ;)
I also like how epoxy bonds, and use sandpaper prep (150grit) along with an acetone wipe. Layering glass works well with epoxy, as do filler beads or fibers for thicker gouges. In my experience, it takes a couple weeks to ensure a good cure for the epoxy before final shaping and sanding. Keep the pics coming, it's fun to watch repairs in progress.