Steps in Building a SCAMP sailboat
Links to all my scamp building pages.
Finishing the Outside Hull
Now that my SCAMP has been turned over I'm ready to start finishing the bottom.
The bottom and the first strake gets a layer of glass so smoothing and filling this area will be my first task.
I went around and scraped any drips and sanded any bits of epoxy. This allowed me to have a good look at the various seams. There are a few spots where the planks were glued that need a bit of filling. I also need to trim the centreboard case and fill the connection to the hull.
I used the Japanese pull saw to trim the centreboard. I then went around with the sander and evened out the side of the centreboard. They were just a bit proud of the bottom. I used 60 grit on the random orbital sander. The vacuum got all the dust off and I was ready to fill various spots.
I went around with un-thickened epoxy and touched up all the spots where I will be filling. I dripped some in the few small gaps between the planks. I then went around with thickened epoxy to fill any screw hole in the bottom, any gap between the planks and around the centreboard case and along the bottom and first plank connection. I'll need another round of filling but I'll wait till this has set.
There is nothing that can make sanding look interesting. I'm using a scraper to tidy up the underside of the gunwale. The epoxy I did yesterday is still just a bit soft to sand but there is lots to smooth out. The scraper can remove lots of irregularities. In particular, I'm cleaning up the plank joins. Once that is done I can fillet. I'll wait till this is done before starting to fair the hull.
The shop is nice and warm, there is good music playing and I'm just spacing out gradually smoothing out the hull.
I've gently rounded the edge of the bottom so that the fiberglass could go around. This also showed me where I needed to fill so I would get an even radius.
Once I've filled the low spots I'll go back and round some more.
I also went around with soft thickened epoxy, and filled the plywood seam and uneaven spots around the centreboard. There were also a few spots along the bottom edge where the radius needed filling. I'll have to leave this for a couple of days so I can sand easily. The shop is quite cold and the epoxy gums up if sanded too soon.
This is East System Epoxy and I've really enjoyed working with it. Not only is it the cheapest epoxy I can get but it is NON Blushing. I've been using it for 3 years and so far not a single instance of blushing with the regular hardener. It sets well and I can usually start working on the dried epoxy overnight. I can even sand if I kept the shop warm.
I don't recall having any trouble wetting the glass out. I apply it and it takes a bit of time to soak in and wet but it is not troublesome.
It seems to soften when heated a bit more than other epoxy I've worked with but that's at quite high temperature or if sanding in one spot so long and hard that the surface warms up.
After rounding the bow I looked at it and though the curve was too large a radius. It looked odd against the curve of the forward panel. I filled the curve I had sanded with thickened epoxy and rounded it again this time with a sharper angle. It looks better and is more consistant against the bow panel.
I used a rounding bit in the router to put a radius on the centreboard opening. The bottom glass curves into the centreboard for an inch or so.
I sanded any rough spots and vacuumed the whole boat in preparation to the glassing.
The glass I get is 60 inches wide and unfortunately the bottom and sides of the SCAMP are a couple of inches wider. I decided to cut the glass in 3. 2 sides and a bottom. I planned for an overlap around the edge of the bottom and at the front.
I did not take a photo but I trimmed the glass to the exact curve of the plank. On the bottom (which is on top because the boat is upside down,) I allowed for a couple of inches of overlap.
I used a paintbrush and a squeegee to spread the epoxy. It worked fine. The glass went on very tidily so there will not be much clean-up to do before adding the bottom glass.
I waited for a couple of days so the epoxy would be easily sandable then went around and scraped and sanded the rough glass edge on the bottom of the hull. I have a new batch of glass still in the package. I had got an extra length when I realized that the 60 inch wide glass would not cover the sides properly.
Brushed and vacuumed the bottom clean. I rolled out the new glass onto the bottom and the back transom. Tape is just there to temporarily hold the glass so I can position it. The glass feels softer than the other 6 oz glass cloth I had. I took a big breath and started mixing epoxy. The clock is now ticking.
I started at the back panel and made my way forward. There were no particular difficulties but this new cloth does not wet out as easily as the previous one. Different coating maybe. Since I'm using the same batch of epoxy I know it is not the resin.
I made up smaller batches so my resin would not start kicking off before the glass was saturated. It worked fine. I did not spread the resin as tidily as I like but it's done.
After finishing the glassing of the bottom I went around and got rid of a few drips and made sure everything was saturated. I noticed slightly raised strips back to front. It's almost as if the glass had expanded in the one direction. I pushed the contrast in the picture to exagerate the effect for the photograph. There is no air under the raised spots, just slight bulge. It's not glass that's floated up because of too much resin either. This is a new issue for me.
If the glass does not raise any more then it will not be a problem. It was perfectly smooth when I put the dry glass down and even after I put the resin on. It happened about 30 minutes after wetting. The epoxy is just about to kick off and is already thick.
If the glass is too far raised I can sand it flat and add another coat of glass.
At this stage I got bitten by a stray cat and had to be treated in case he was carrying rabies. Luckily both the cat and I are just fine but it took a few days and slowed the boatbuilding efforts. Read about the rabies scare here.
After the epoxy set I had a good look at the raised glass ridges and they were better than I had feared.
After scraping any protruding glass edge and cleaning up a couple of drips, I set up and made the fillets I had been putting off doing. I find it difficult to make nice even fillets. I did my best.
I had mixed more thickened epoxy than I needed and I used this to help blend the end of the fiberglass that I had folded over the edge onto the garboard. I have a wide spatula and it did quite a smooth job, if I say so myself. This is all quite unknown territory for me. Once set I scraped and smoothed out the side plank and got ready to fill the top and any irregularity on the side. The cloth pattern was still quite prominent although well saturated. Photos don't show much because the filler was just about the same colour, sorry.
I had a bucket of phenolic microsphere so that's what I used. It goes on as quite a brown coating but is nice to work with. Much to my surprise the bottom ridges filled in very easily and other than a few trowel marks the coat was smooth and thin. It looks blotchy because there are high spots and ridges and glass edges along the sides of the bottom.
At this point the world stood still as I sanded, scraped, sanded ... you get the gist of it. I find it very difficult to motivate myself at the sanding stage. I also spent some time cleaning up the fillet so it is as even as possible. It's a bit tricky because the angle between the boards is not constant. This is where an auto body person would have the advantage.
Sanding progress is hard to show. I spent a day just going over the fillets and smoothing them out. I will need to do another filling session but the hull is quite smooth now.
I've gone over the hull and everything is smooth. There are a few spots that need some filling and I need to repair a couple of spots where I sanded through the epoxy to the wood. I guess I'll touch up with resin.
I ordered my paint, from the same guy who was bringing in the fancy pintles and gudgeons. Bronze if you please, they'll be the prettiest things on the boat.
I looked at all kinds of paints. I'd had good luck with plain yacht enamel from Epiphane, but I wanted a harder paint for this boat. It's much harder to move her around and retouch the bottom so I would prefer not to have to do it very often. I finally decided on single part urethane. The 2 part paint is quite toxic and I don't think the level of preparation I can do warrents the extra trouble and risk. The colours are also nicer. I had used single part urethane to paint my keelboat tender and it was bomb proof.
As I was sanding I remembered that I had covered the water ballast filling hole and needed to open it up. I did this and realized that I had a bit of resin stuck in the threads. I used paint stripper to remove it but it took quite a lot of time and careful scraping with a wooden skewer. I dared not use metal on the soft brass threads. That's done now. I crawled under the boat to try the plug to make sure it went on without any trouble.
If you decide to build a boat be careful. These tools can be dangerous. If you don't know how to safely handle something find out. There are lots of forums out there.
This web site reflects my personal ideas and doesn't represent anyone else's point of view. I don't claim to be an expert in anything, just some little old lady muddling along.