Today I tackled beginning to repair the holes cut in the side of the trailer for various things. I'm calling this Fiberglass 102, because I had, in the past, done some repairs to fiberglass canoes, but only to cracks or punch holes, never something big. So I figured I'd test my wings on the smallest of the holes, the one with the water fill opening that went to the tank but then the previous owner never connected to the sink. Had to start by removing the fitting- not too difficult with my wonder-tool, the oscillating saw.
But, let's back up a step. Before this, I had to go get all the stuff for the fiberglass work. I had no, zero, none of the pieces of that puzzle. It took me three stores to get what I needed, and I am sorry to tell you that Lowe's (which I like best of the DIY stores) did not have the fiberglass mat. I did find it at Home Depot. Came home with woven fiberglass (comments later), fiberglass mat, spatula-like levelers, 2 throwaway brushes, resin and hardener, acetone, and gloves (I think we have some, but I couldn't find them). I wanted a little roller, but couldn't find one. Frankly, even though these are places that don't make my "I hate shopping" antennae vibrate, I'd had enough fun in stores.
Next step, sand the area around the hole well on both sides with coarse grit. My oscillating tool does sanding too!
Then, thoroughly clean both sides with acetone. Another side story. I have been hoarding and rationing a bottle of acetone since my lab rat days because I thought it was difficult to get. Ha! You can buy it in big cans. I thought a quart would do me.
Next, cut a plug of cardboard the size of the hole, and tape it to a larger piece of cardboard.
Cover it with plain old wax paper. The resin will not stick to wax paper at all. Just stick that in the hole from the outside, and tape in place.
Cut some pieces of fiberglass that are larger than the hole. I used three pieces of the woven fiberglass. Lay them aside.
Next you mix up the resin. Here's where I have to tell you that despite all my reading and video watching, just this evening, I found something even better. On the Fiberglass RV forum there is an entire long thread dedicated to doing fiberglass repair on these trailers. It's written by a pro fiberglass guy who also owns one of these trailers. Let me say here that fiberglass trailers are sort of an oddity with special needs all their own. They are most similar to boats, but this forum is geared to this particular application.
That said, the first thing I learned that I did wrong is illustrated in the next picture. I used an old plastic container to mix the resin and hardener. Don't do this! The plasticizers can dissolve into the resin mix and affect how it hardens. Use paper cereal bowls or hot dog boats. I think I have some bowls. If not, I'm sure there's another store in my near future.
Anyway, I'm a little OCD (don't laugh... it's truly only a little), and I had no "feel" for the mix of the resin and hardener, or how much I'd need. So I used the smallest measurement they gave which was an ounce of resin and 10 drops of hardener, and did it right. Mix with a stroking motion, not circular, so you don't get air bubbles. Now you have about 8-12 minutes, which is why you get everything else ready first!
Spread a thin layer of the mixed resin on the inside of the wall, large enough to completely cover the area where you will put the cloth. Press the cloth in place and work resin into it until there are no air bubbles and it's completely translucent.
Here's the second error, according to the RV forum guy. He says never use the woven fiberglass on these RVs, only the mat. I think I'm not going to worry about this on the smaller holes. Anyway, not on the two I've started!
Put three layers of glass on by this method, and let it set up for 2 hours. The brush can be kept soft in acetone. I ended up needing 1.5 batches (ounces) of the resin mix to do this.
Sure enough, two hours later, the plug and wax paper pulled right off and the backing fiberglass was nice and hard.
Then I filled in the hole with multiple layers of fiberglass, soaked in with resin just like the other side. You want multiple layers of glass and a minimal amount of resin- just enough to wet it. The strength is in the glass fibers.
Another thing I didn't do wrong (yet), but now know I must do better. I need to sand out a dip around the old screw holes and fill them with mat, not just resin. The resin alone is brittle.
It's hard to tell in the picture, but the hole is filled in very nearly to the level of the exterior surface. To finish it you use a filler. Like Bondo. I've learned that Bondo is polyester based and would probably be fine here. But other videos said a fumed silicon powdered product called Cabosil can be added to the resin to make a paste, and it sands really easily. Yet more videos and people say it is hard to sand but has more strength. Who should you believe? Anyway, I ordered a quart of Cabosil. I can't finish the job till that comes, but at least there is not a hole to the outside.
I got one more of the small holes backed, and decided that was enough fiberglass for the first day. The first throwaway brush was shot, and I decided not to get the other one messed up till I was prepared to do all the rest of the holes. The forum guy even gave directions for dealing with the BIG air conditioner hole. Wow! I finally think I'm getting good advice.
My other goal was to get the ceiling board down. That turned out to be pretty easy. Here's the big joke. There was no wasp nest there. Apparently the one wasp I kept playing tag or keep-away with (depending on whether you take the wasp's point of view or mine) was just that. One wasp. Maybe looking for a nest site. He won't nest there now. The inviting space is gone.
In other news, I posted some closeup exterior pictures on the forum, and it looks like exterior work and paint are going to be in the near future.
It was a beautiful day (although on the warm side for me), and I'm so glad I got all this work done on the trailer. Tomorrow it's back to the "real" job, but I hope to continue the trailer redo. For one thing, the first part of the exterior job is a real scrubbing. That shouldn't take much thinking power, or be a big mess with lots of tools, so hopefully I can work on that is small bits.
The biggest annoyance of the day- little biting flies, but I didn't let them get the best of me.
(BP -16 and counting)
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