After the boat was turned over we spent nearly two days planing and sanding in order to get it fair. We did not use the pneumatic sanders in favor of the long boards. This required a whole lot more work on our part but this kept us from easily over sanding any single area. The temporary frames on the centercase was removed. We also figured out where the laps in the glass cloth would be and rebated back the wood. In order to get the boat fair there are a couple of things that you do. Technique in how you hold the plane and longboard are crucial but more than that you really need to take your time and feel the boat. As I would sand, I would pause every so often and feel the area starting inboard and working out and forward and aft. The high spots that still exist stand out fairly prevalently. We just tried to make sure that we did this (it was actually hard to communicate this to everyone because it seemed that some people really just wanted to sand or plane like mad). After we got the boat to what we thought was fair we dusted it off and then got a fair batten and ran it all the parts of the boat to see if there were still any bumps or hollows. In figuring out the glass cloth laps we actually cut the cloth and then laid in down on the boat, marked the area and then sanded to ensure we had it correct. We really wanted to make sure that the laps did not stick up because if it had to be sanded down that would negate the entire purpose of the laps. If the the high in the lap needed to be fixed when it is being painted then that can also take an extraordinary amount of time. We then vacuumed the enitre hull and proceeded to fill whatever gaps that exist with filler so that no air can be trapped inside the the boat is glassed.
During the final stages of sanding we also started installing the chain plate in the topside. This is 8 mm thick glass plate that goes from the sheer to the chine and is about 100 mm tapering to 40 mm wide. This is for the shrouds. When the boat is rigged it is going to having a fore-stay and two shrouds that are raked aft and no backstay. We installed this plate in nearly the exact same fashion and we did for the plate on the transom, router, chisel, sand paper. In order to get them from sliding around while the epoxy was drying we got two lengths of wood and screwed them over the plate and then used a third length and wedged it in from the floor. Once the plate set, we sanded back the thickness of another piece of glass about 40mm wide. The extra piece of glass ensures that there is a good stick between the plate and the final laminate sits fair.
The next step is applying a sealer coat to the wood. We did not have enough of the actual sealer so instead we just used the same room temperature cure epoxy (WEST system) that we have been using for the majority of this build. Wood has a natural wicking tendency and so if we did not seal in and put the glass and resin down then the resin that should be in the glass would get soaked up into the wood, thus ruining our fiberglass job.
The next step is actually putting the glass down. This laminate, EDB400, requires extra special care because it is on the outside and we are using the room temperature cure epoxy. When the owner goes to have this boat painted it needs to look perfect, for him and his pride but also for us. So when we lay down the glass and pay attention to the laps and folding the glass over onto the deck (for structural integrity and stiffness) we need to be very careful. We decided to do this part of the job in two different sections, in order to reduce the difficulty factor. We also went through all of the steps of vacuuming. The main thing that I would like to mention here is about how the glass is folded onto the deck.
While we were putting on the resin we made sure that we had extra sheets of cardboard down so that if resin was dripped down onto the floor it would get on the card and we could just remove it and stay clean. So when we got the glass and resin down properly from the center line working outboard and then down the topside it was time to get the 50 mm around and onto the deck. This was done both with brushes and squeegees, but there were some ways to utilize these two tools. When we used the brush and soaked the glass with the brush and kind of stuck it to the deck. Then we would go back over with the squeegee and get a really fit. If we worked the other way around we had difficulties. The brush tended to dripped resin down onto your hand and glove and with the squeegee we were simply not able to get the resin onto the job.
Chris this is an excellent blog and shows that you indeed have an indepth understanding if the issues involved throughout the process of fairing and sheathing the exterior skin.
ReplyDeleteKeep up with the good work.