Rudder tip farce continues

OK, so yeah, the fun times keep on coming. First thing today I set about sanding off all that filler primer I shot Friday evening. That turned out to be more fun than I expected – that stuff really loves to clog sandpaper. I was taking lots of pauses to knock the crud off my paper, over and over again. But finally I got it all removed from both fiberglass pieces – well, mostly. There were some low spots where a layer of primer remained, and I decided that was fine since I’d be covering the whole thing with an epoxy skim coat again.

And so the epoxy dance began again. The idea here is to lay on a series of coats to build up a little thickness, and also to end up with a textured surface to provide a sanding guide (eg you sand the skim coat until the texture goes away). So you mix a batch of epoxy, coat the piece, squeegee most of it off, and then use a roller to even everything out and apply some texture. Then you let that coat tack up (about an hour or so in the current cool temperatures), then repeat this a couple more times.

Now, here’s the fun I had with this procedure today. First off, my nappy paint roller shed a fair bit of junk into the epoxy. That was almost enough to make me call it a day again, but I decided to soldier on, figuring I’d be sanding this down anyway. I guess there are worse things in the world than having odd fibers under the primer. Worst case, I sand it all off (again) and repeat this process (again). I think part of the problem was that the low temperature made the epoxy a lot sticker than it would have been otherwise.

The real fun came when I went out to apply my third and final epoxy coat of the day. I’d mixed up a batch, painted it onto the stab tip, and was just getting started on the rudder tip when…I bumped the stab tip accidentally, sending it off the workbench and onto the floor. Which meant that that epoxy I’d just laid on picked up all the dirt and random stuff on the floor where it landed. At first I tried wiping it off with a dry paper towel, but that wasn’t removing stuff too well, so then I switched to a towel soaked in acetone – which works well for cleaning up uncured epoxy. That did a good job of removing the epoxy I’d just put on, but I think it also removed some of the previous two coats. Kind of hard to tell. In any case, about all I felt I could do was to go ahead with that final coat of epoxy and hope it was enough for sanding later on.

Later, I went and reread some of the VAF fiberglass info, and another recommendation from Dan Horton (a guru-level composite guy) was to skim coat with a different product instead of raw epoxy. System Three Clearcoat is mainly used for waterproofing wood, but according to him a single coat goes in nicely, lays itself down smooth, and has a long enough pot life to have good working time. So I ordered some of that stuff, and will probably try it out the next time I need to shell out a fiberglass part. The whole half-day odyssey of multiple epoxy skim coats just isn’t doing it for me.

Now, let’s just hope that I won’t be trying that stuff on these same stupid tips. I’m really hoping that I can finally get these parts done and mounted, and move on to something else, maybe try that new epoxy stuff on the rubber bottom cap. At least with all this learning I know that the micro I’ve put on there needs more finishing before I shoot primer or anything like that.

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