Steps in Building a SCAMP sailboat
Links to all my scamp building pages.
I've just spent the last few months sanding, I can now paint
There is no way I can make sanding, filling, sanding, ... look interesting. I have a lot of trouble motivating myself to do this. It's taken an eternity to get the hull to a stage where I would feel happy to paint.
To compound the problem, the hull is quite motley from various filling and sanding so it's hard to see any irregularity. I feel the hull mostly. The hardest areas are the fillets. Mine are not perfectly smooth and regular so I've had to do a lot of sanding and fairing.
I'm not very skilled at finishing, I will fill and fair an area but no matter how much care I take, there is a limit to my current skill level. It's better than in my other boat projects, but it's not as good as I expect of myself.
Eventually I reached a point where I said "good enough."
Marking the Waterline
I had spent hours trying to figure out a colour scheme and eventually I settled on something I liked. It involved having a colour change at the waterline with a contrasting stripe. Part of the decision is to have a darker colour around the waterline so that algae and other stains don't mark the boat too much. I always had to clean the skerry at the waterline and I'm hoping to have to reduce this.
My first attempt was using the laser pointer. It's a level thingie, that is used mainly to find studs but has various spirit levels and can be used to make straight lines.
I set it up at the height I wanted and tried to take measurements rotating the level. Try as I may I was never able to get an accurate position. My hull is level across, but slightly inclined back to front, and even after several hours of fiddling with positions and angles I never got what looked like an accurate water line. I was comparing to the plans. So I scrapped this method and tried something else.
I saw this described in an old book so I though I would try it. I set up 2 boards front and back. These were perfectly level and lined up to the height front or back where I wanted the waterline to lay. I then stretched a small line between the boards.
Now comes the tricky part, I sighted the stretched line with the boards and marked the spot on the hull. So essentially I made a mark where the line hid the spot I was marking.
It wasn't particularly easy but it worked surprisingly well. A small sag on the line gave me some trouble but after putting weights on the board supports I was able to keep the lines tightly enough to eliminate sag.
I used 2 stepladders with a small spacer at the bow. The photo was taken from eye level and shows the board lower that it actually is. It was level to the bow waterline.
The stern board was held up by the little roller stand I use with the table saw. It is sturdy and kept the level nicely. It's easy to adjust the height too.
I moved both the boards as close to the boat as possible.
I drew in a faint black line in Photoshop to show where the string was. It was simply a matter to crouching down and lining up the string with the top of the board by moving my head up and down. When the string lined up with the edge of the board I made a mark on the hull at that point. I did this front and back and marked the points on the hull.
I had to move the string further out front and back in order to get it close enough to the hull to get a proper view but although this took time, it seemed to work well.
I ended up with what looked like a pretty ragged bunch of points but when I started joining them the waterline was quite fair.
After doing this on both sides of the boat I checked to see how comparable the waterline were port and starboard. It surprised me that after measuring from the edge of the bottom to the waterline, the greatest discrepancy was only 5 mm. between the 2 sides. I deemed that good enough and ran the tape along to make a smooth line.
Since I plan to make a contrasting stripe at the waterline, I will wait to make this line till I have actually launched the boat and actually marked the real line. I'll be able to paint this while the boat is on the trailer.
Making an edging for the top
I used a block of wood to slide along the gunnel and mark an even line along the top of the hull. The tape went on without any trouble. Just because I could I dusted the boat really well and painted the stripe.
I was surprised on how well the paint went on.
I'm using Brightside polyurethane paint. I have used it on the Apple pie tender I built for my little Keel boat and the paint was almost indestructible.
I applied the first coat of paint to the bottom after burnishing the tape. I had taped the opening to the water ballast tank and the opening for the centreboard.
I painted by slices about 2 feet wide. I use a small roller to apply the paint and a foam brush to smooth it out. The foam brush gets rid of bubbles and gives a smooth finish. The smoothing out is done towards what you have already painted.
Using nice paint makes it so much nicer to work with. The covering power is very good and after just one coat I can't see any of the hull and the surface is good.
My shop is cold this time of year and I heat with a wood stove. If I keep the draft wide open, I get a lot of air being moved out and the stove acts to ventilate the shop.
I'm wearing a vapor mask the whole time I'm in the shop to paint. I think the fumes are quite nasty.
Instructions are to sand with 220 before re-coating. It took a few days before the paint was hard enough to sand. I could have re-coated earlier without sanding but I wanted to sand and smooth out the hull a bit more. I found that I had left lots of small scratches (which had mostly disappeared with the first coat though.) The paint filled really well. I found 220 grit to be aggressive so I switched to 350 and this worked well.
After sanding and dusting I re-coated the hull. I don't have a lot of dust but I'm getting tiny hairs. I have cats and I suspect I'm bringing cat hair on my clothes. Not much I can do. I had vacuumed myself and used a sticky roller but still got some hair.
The paint has gone on very smoothly otherwise.After a light sand, I put a third coat on and let it set while I started cutting the metal show that will go over the bottom of the skeg.
After removing the tape, cleaning up a couple of small spatters, I checked that the middle section was ready to paint, sanded a couple of rough spots and taped the junction.
The colour of the hull is so motley with the various layers of resin, cloth, fairing compound, glue, fillets, that it's hard to see if there is any scratch or bad spot. I have to feel rather than look.
Other than a few cat hairs in the paint, the first coat went on without any argument. White does not cover nearly as well as blue and I expect to need at the very least 3 coats and possibly 4. The first coat will be sanded quite a lot and will help fill any small imperfection.
Because it's quite cold the paint does not set or dry very fast. 2 days later I went in to sand the first coat down. It's really acting a bit like a primer. Second coat is on and coverage is much better.
Third coat of paint is one. I removed the tape. I'm using: Frog Tape 82021 Pro Painter's Masking Tape, 1.5-Inch by 60-Yards, Green, Single Roll by FrogTape (Link is amazon) It's crazy expensive for masking tape but it is really working well. It also comes off easily.
That's it for the sides. I still have to paint the front and back transom. They are ready but I have not quite decided if they are going to be white or blue. Besides I want to work on the top edges so they blend in better with the top of the boat.
I'll let the paint harden for a week or so then I can turn it over and get on with finishing the top.
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 someone muddling along.