Kaimusailing

Kaimu s/v Kaimu Wharram Catamaran

Vessel Name: Kaimu
Vessel Make/Model: Wharram Custom
Hailing Port: Norwalk, CT
Crew: Andy and the Kaimu Crew
About: Sailors in the Baltimore, Annapolis, DC area.
24 May 2016 | St. Marys, GA
22 May 2016 | St. Marys, GA
21 May 2016 | St. Marys, GA
16 May 2016 | St. Mary's, GA
12 May 2016 | St. Mary's, GA
10 May 2016 | St. Mary's, GA
06 May 2016 | St. Mary's, GA
01 May 2016 | St. Mary's, GA
30 April 2016 | St. Mary's, GA
27 April 2016 | St. Mary's, GA
25 April 2016 | St. Mary's, GA
24 April 2016 | St. Mary's, GA
22 April 2016 | St. Mary's, GA
19 April 2016 | St. Mary's, GA
15 April 2016 | St. Mary's, GA
11 April 2016 | St. Mary's, GA
10 April 2016 | St. Mary's, GA
08 April 2016 | St. Mary's, GA
06 April 2016 | Jacksonville, FL
06 April 2016 | St. Mary's, GA
Recent Blog Posts
24 May 2016 | St. Marys, GA

Search for Perfection

There were a couple messages about the scarf jig and cutting scarf bevels. The jig has to be made with its faces exactly perpendicular to the saw table. The blade has to be adjusted to be exactly perpendicular to the table as well as parallel to the angle guide slot. Some blades are slightly out of [...]

22 May 2016 | St. Marys, GA

Using the Scarf Jig

Here is a picture of the scarf jig. You can see it has a rib on its bottom that slides in the groove in the table saw that usually has the angle guide sliding in it. The jig has a 10:1 angle with respect to the table saw blade. The jig was made with two faces, both having the 10:1 angle, one face [...]

21 May 2016 | St. Marys, GA

Scarf Bevels

The storms came and caused a great deal of trouble. The Toughbook got wet and now is dead. A repair parts computer is on order to hopefully repair it. Meanwhile the old Lenovo Thinkpad is serving as backup.

16 May 2016 | St. Mary's, GA

Beam Work

I hit a frustrating snag with the #3 beam construction trying to get too far ahead too quickly. I glued two planks together, one cedar plank on edge glued to a horizontal fir plank, both with scarf bevels at each end. The pair were carefully measured to fit on the end of #3 beam to extend it from port [...]

12 May 2016 | St. Mary's, GA

Pain and Disappointment

It's time to write about pain. I made a mistake and stuck my thumb into the whirring trim router. Ouch! I didn't want to see what had happened, I guessed that my thumb would be half chopped off. Before any blood started flowing I jammed my hand into a nitrile glove. I didn't have my first aid kit [...]

10 May 2016 | St. Mary's, GA

Beam 3 Build Pt. I

The beam brackets were wire brushed to remove any loose paint, then painted with a rust preventative paint.

Search for Perfection

24 May 2016 | St. Marys, GA
Capn Andy/Hot
There were a couple messages about the scarf jig and cutting scarf bevels. The jig has to be made with its faces exactly perpendicular to the saw table. The blade has to be adjusted to be exactly perpendicular to the table as well as parallel to the angle guide slot. Some blades are slightly out of true and it is not a manufacturing defect, it is a compensation for when the blade heats up during cutting. If you get non-perpendicular angles on both sides of the blade, split the difference.
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Another source of errors is the distortion of the wood itself. If you are seeking perfection you will have to resaw and surface planks that aren't true. They can have twist or cupped faces. They can have faces that undulate due to warping when the planks age. Some may come right out of the saw mill distorted. If you are laminating planks into a beam, sometimes you can laminate together planks that have the same amount of twist or other distortion that is similar between the two planks. A plank can be used as a partial near the end of the beam. There will be less effect on the shape of the beam, however if a distorted plank is in the middle of the beam, then the whole beam will be twisted or curved. If the beam can be laminated before assembly into the boat, it can be trued before assembly by making it slightly oversize, enough to keep the low spots within spec. Excess can be planed off, but a dished area can result in a dished out area on the finished beam. Epoxy and fillers can compensate for lots of discrepancies and still manage to create strong glue joints.
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Perfection is desirable for cosmetic reasons, but hidden areas will be fine with joinery that is utilitarian, however some will find that objectionable and spend a lot of effort to make even those hidden areas perfect. When my grandfather made something that was less than perfect, he said it was “rustic”, on Kaimu it is “workboat finish”.
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Meanwhile on the Brit cat next door, the search for perfection continues. They are using a new paint called “Quantum”, which contains a higher percentage of solids than most other LP paints. It is repairable, which means it can be feather sanded and repainted on any future damage.
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The ordeal of preparing their boat for this paint has pushed the Brits to the edge, but finally they had the paint rep coming over with a spray painting rig, after they had tried to roll the paint and found the results to be not acceptable. The picture is of the underside of their catamaran and the results of a first coat of the glossy paint. Its shiny surface magnifies any surface imperfections, but their hundreds of hours of preparation paid off with a lustrous finish.

Using the Scarf Jig

22 May 2016 | St. Marys, GA
Capn Andy/Hot and Humid
Here is a picture of the scarf jig. You can see it has a rib on its bottom that slides in the groove in the table saw that usually has the angle guide sliding in it. The jig has a 10:1 angle with respect to the table saw blade. The jig was made with two faces, both having the 10:1 angle, one face reaches right to the saw blade when the rib is seated in the groove on one side of the blade, the other face does the same when the rib is seated in the other groove on the other side of the blade. It is necessary to cut the scarf bevels with two cuts, and the plank has to be flipped for the second cut, and the jig has to be set up on the other side of the blade. If the saw was able to cut a 5” wide plank, on edge, with one pass, then the jig could be made with only one face and all cuts would be made in one pass.
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After making the first cut, the plank is flipped over and a thin slat is inserted into the saw cut to that the plank can be clamped to the jig without the saw cut squeezing shut. I call the thin slat a kerf spacer. The second cut only has to be deep enough to cut the remaining wood left by the first cut. It takes some skill to get the second cut to be flush with the first cut. It can come out at a slightly different angle or be offset to the side slightly. The end product can be cleaned up with a power plane and belt sander. It is a very efficient way to make a scarf bevel.
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I was trying to get more consistent with the scarf bevel cuts and I finally got it figured out. I have cut about 20 scarf bevels so far, so it is about time. The first step in getting control of this technique was to always start the scarf cuts on the same face of the jig. I labeled this face of the jig “1st” as I would always be making the first cut using that side of the jig. I chose that side because I had a feeling that most of the better bevel cuts were made by starting on that side. Next I decided to use the marks that I made on the plank to line up the plank and jig. I always take a 10:1 triangle, which you can see in the picture, and mark the 10:1 angle on the end of the plank on both the top and bottom edges. Then I draw the line marking where the saw blade should begin the cut on the face of the plank. To gain consistency, I lined up the cut line with the leading edge of the jig. After I cut the first cut this way, I could see it was in a good place, just a bit offset, so I began cutting the first cut on all the bevels by lining up that mark with the leading edge of the jig.
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Next I made the second cut using the other face of the jig and now the plank was flipped over on its other edge. The mark for the cut line was placed again at the leading edge of the jig, but now the cut came out offset a bit from the first cut. This was caused by the leading edge of the jig being a slightly different distance from the blade. This scarf bevel was not too bad and could be cleaned up with a plane. Now I used the same procedure for a second scarf bevel, and on the second cut moved the cut line ahead of the leading edge of the jig by about 3/16”. This scarf bevel turned out better, but there was a discrepancy between the 10:1 angles of the two jig faces, so the two cuts were not exactly flush. Still easily cleaned up with power planer or belt sander.
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Because the 10:1 angle cut with the jig also depends on how the plank is pulled through the saw, the discrepancy can be compensated by just holding the plank a little bit outward on its way through the saw. The distance between the cut line and the leading edge of the jig also had to be increased to about 1/4”. Now the scarf bevel was nearly perfect. There is still some variability in the cuts, but by using marks and writing down notes on adjustments, the bevels are much more consistent. There are many more planks to get out and thus many more scarf bevels to cut, so getting a handle on this procedure will pay off.
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This jig was made for a specific table saw and if I end up cutting scarf bevels on another saw, I could make an equivalent jig, probably even more accurate.

Scarf Bevels

21 May 2016 | St. Marys, GA
Capn Andy/Thunderstorms
The storms came and caused a great deal of trouble. The Toughbook got wet and now is dead. A repair parts computer is on order to hopefully repair it. Meanwhile the old Lenovo Thinkpad is serving as backup.
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The strong winds of the thunderstorms blew the tarp part way off one of the work tables, uncovering some of the power tools, the Toughbook, a the roll of paper towels, and a bunch of other stuff. It was dark and I had clamped a plank onto the #3 beam and forgot it was there. I walked into the clamp, lacerating my scalp. It was raining and I could see also red drops falling to the ground. I tried to use the paper towels to mop my head, but first had to wring out the rainwater. There was a lot of blood and soon I had a mass of paper towel mush, sopping with blood.
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I didn't find out about the Toughbook until morning. It didn't look like it had been flooded, but it didn't boot up. After pulling out the drives and battery and letting it air out, it still didn't fire up, even after two days. Normally I could use the smart phone to do a lot of the internet chores, but I had used up almost all my data allowance watching the America's Cup World Series in New York. Now I had to be careful not to use the phone for data for a whole week and a half, until the usage cycle resets.
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The two neighbor boats in this yard had dark mesh sun shades, large and tied onto PVC and wood framework. The winds affected both of them and they had to be rebuilt. PVC isn't very strong. I saw that both sun shades were using PVC pipes with pipe joints between them, and it was the connecting fittings that broke, not the pipe itself. I had seen online Quonset Hut style shelters using PVC pipe bent in arches. I think one of those structures was crushed by a heavy snowfall, but I think that was the only
one built like that that failed.
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I ordered a 5" random orbital sander from Harbor Freight along with some replacement power planer blades. The order wasn't shipped until the Thursday after it was ordered on Monday. Sanding disks had to match the vacuum hole pattern of the sander and the Norton Premium Gold paper that worked so well wasn't available in that format. After some research I ordered Klingspor paper in 60 and 120 grit, the total coming to just under forty dollars for a 50 pack of each paper.
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The beam construction was proceeding slowly due to the requirement of prefinishing the external surfaces of the planks before gluing them into the beam. This was necessary because there was no room to even get a small paintbrush on some of the beam surfaces. Another problem was forcing the beam into the beam brackets. These are not the usual Wharram design, which are like angle pieces lag screwed into the beams, these wrap around the beam and the fit was tight.
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The scarfing jig was working better and better. I was trying to find out why I was getting inconsistent results, so I began carefully noting any variables that could affect the angle of the scarf bevel. I began using the same side of the jig every time. I found the thing that most affected the bevels was the condition of the lumber, was it warped, twisted, or curved? If the lumber can't lay perfectly flat on the table saw, the angle of the cut changes as it passes through the blade. Sometimes the saw jams, stalls, and pops the breaker. I think I will get this process organized so that all the scarf bevels will be perfect except for those cut in warped pieces of wood.
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The picture is of the latest pair of planks with scarf bevels cut with the table saw. These came out well and didn't need any corrective planing and haven't been sanded yet.

Beam Work

16 May 2016 | St. Mary's, GA
Capn Andy/Hot and humid
I hit a frustrating snag with the #3 beam construction trying to get too far ahead too quickly. I glued two planks together, one cedar plank on edge glued to a horizontal fir plank, both with scarf bevels at each end. The pair were carefully measured to fit on the end of #3 beam to extend it from port to starboard. My measurement was way off and the pair of planks couldn’t be used. The error made no sense, not off by and inch or even by a foot. Not off by any logical amount. I had to set them aside to be used for #2 beam.
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The next day I felt I had to make up for the error. I cut scarf bevels on the ends of four planks, two cedar and two fir. The fir planks had to be cut down from 5 1/2 inch width to 5 inches. My scarf jig had maybe a one degree error between the two bevels, each scarf had to be cut twice on the table saw, the blade depth could not cut the 5 inch width in one pass. I found an even greater error caused by my handling of the wood as it went through the saw. I could induce errors in the angle of the bevel as well as causing the saw not to cut squarely vertical. My cuts were getting more accurate as I got more experience. Out of the eight bevels I cut, two or three were bad.
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The bad bevels could be cleaned up with the power planer, but I found it was getting dull. The procedure to remove the planer blades is tricky, and sawdust embedded in the planer did not help. I had resharpened the planer not too long ago and was surprised that it was dull already, had I hit some fiberglass with it, or some hidden staples in the wood? I used the dremel tool with a grinding bit to sharpen the blades, then tediously reinstalled them and aligned them. Now the planer really cut well and I cleaned up the bad scarf bevels.
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Along with the four planks there was a remnant fir plank with a scarf on one end and square on the other. It was about 3 feet long. My scheme for producing planks for scarfing was to start with a plank that had a normal square end and a scarf beveled end, and use the square end at the end of the laminated beam. If I started with all full length planks, all the scarfs would land in the same place, so I had to stagger them by using different lengths. The most efficient way to do this was to cut the scarf bevels in the middle of a plank, producing two shorter planks with their original square ends on one end and a scarf bevel on the other end. Kill two birds at once.
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These short planks that had a scarf bevel at one end were used to start laminating the beam, so I had to plan carefully that scarf joints in the six layers of planks didn’t fall at the same spot in the beam. The 3 foot shorty meant that there was a 5 foot shorty, and it was already used in the beam. It was fir and there were no extra cedar shorties, so both of them had been used in the end of the beam.
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My idea was to use the 3 foot shorty to put an end on the “error planks”, the two I had glued together and set aside earlier. The shorty was fir and would make one end of beam #2. The cedar plank in the “error planks” needed a cedar plank scarfed to it, and the additional plank had to end the same as the 3 foot shorty. So, I took an 8 foot cedar plank with scarf bevels at both ends and mated it to the “error” cedar plank and lopped it off at the end of the 3 foot shorty. Now I had extended both of the error planks to what will be the end of beam #2. The remainder of the cedar plank also now had a square end, so I used it next to the extended error cedar plank at the end of the #2 beam. I positioned all these plank pieces together and dry clamped them, then removed the clamps and set them aside, after marking mating surfaces for gluing.
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#3 beam could take one 8' fir plank with scarf bevels at both ends, and one 8' cedar plank with scarf bevels at both ends. These would take the place of the “error planks”, extending the #3 beam from port hull toward starboard hull. The planks were put into place and marked for gluing. The problem with my procedure was laminating in place didn’t allow clamping in areas where there was no space. The beams ran between the cross deck structure framing and there was no place to put a clamp, plus this laminated beam was overhead in midair, needing to be aligned and supported all during the process of marking, then gluing, then somehow forcing into position without clamps and getting good glue lines.
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I used aluminum tubing and some leftover large dowels (from the rudder pivot pin work) to prop the planks up overhead. Every time I lifted a plank a little bit, the prop would fall away, down to the ground, out of my reach while I held the plank over my head. “Oh, you bad nasty plank” was not something I would say then.
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The Gluing Process. Let’s say it was hot. My calculations of how much glue I would need indicated that I would need a larger mix of epoxy than I had been using. These are not large batches, usually only 3 oz., but now I went for a bigger mix. My technique of using Walmart barbecue marinade syringes to measure epoxy worked well for using small batches. They were graduated so that you could mix a smaller amount and finish up with almost no waste.
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I made the larger mix and started priming the gluing surfaces as quickly as I could. Just a thin coat with an almost dry brush. Move along. The cedar was rough hewn, so it needed more attention to soak in some epoxy and not leave dry areas. As I came down to the last portion of the mix, the epoxy was definitely starting to thicken, harden, and heat up from its exothermic reaction. Before I could finish with the last bit of epoxy, I had to cast off the blue mixing bowl and the chip brush, they were now fused together.
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This was just the primer coat and it didn’t matter that the epoxy had gone off, it was actually better, as long as the glue was liquid enough to saturate the wood fibers. Now I had to mix the actual thickened glue and apply it, and then put it all together before that went off.
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The heat made me thirsty, but I couldn’t contaminate my water bottles with my epoxy encrusted nitrile gloves, so I kept going. I mixed a smaller mix of epoxy, more like the 3 oz. usual, and added “glue strong”, the 4:1 colloidal silica:milled fibers mix. I used a small chip brush to swab the mixture onto the planks in the areas I had marked. I didn’t stop until I ran out of mix, then mixed more. This is the way to do it, mix only an amount you can use up quickly. It seems that it can resist its setting up process once it’s applied to a surface, provided the surface isn’t blazing hot, out in the sun.
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Now I had to put it all together, clamp, release some clamps and realign, and on the overhead beam parts, screw them together with “composite decking screws”. They are cheap torx headed screws that are corrosion resistant, and the torx driver needed to screw them in comes along in the box. These would slam right through the planks without stainless fender washers preassembled onto the composite screws.
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As it went together I kept my eye on the gluing marks I had made on the planks. I used cut offs from the scarf bevels, that were like 10:1 wedges, to wedge the overhead planks into alignment. The glue would drop down from overhead due to its low viscosity in the high, humid, heat and of course it would land on me, allergic to it.
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The whole mess was together and I rechecked it all, once the glue sets up it would be an awful job if anything was not in line. Then I began stripping off the nitrile gloves, grabbing paper towels and the bottle of vinegar, and flooding the epoxy on my skin, scrubbing it off, throwing that away and going over it again. Then I scrubbed the remainder off down at the communal workman’s sink.
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I found out I had no drinking water anywhere, just one bottle that was almost empty. It was like warm tea, just a couple of gulps. I had to go out and get water.
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I went out in the same clothes I was working with. Sanding dust, smears of glue and vinegar, hair messed up with all of the above, my ungloved hands were OK though, my feet were slowly getting glued to my flip flops.
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I had prepared a shopping list, but I just needed to get water. I was itchy from the epoxy and woozy from no water. I drove into the Winn-Dixie parking lot very efficiently. Grabbed a cart and went into the store.
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I grabbed the things I needed. I had shopped here a few times and knew where it was. I even had a discount card attached to my car keys.
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There were 4 kinds of California oranges here in a store just a stone’s throw from the Florida border. Only one kind of Florida oranges. I knew why and grabbed a bag of California mandarins.
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I had 4 three liter bottles of water and two packs of Keebler Sandie cookies. All the rest of the stuff on the list were in the cart. I went through the store like a tornado, eager to get out and drink the water. The store personnel seemed to understand, this was another one of those boat people from the boatyard, look at that epoxy dust.
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Out of the store and out of the parking lot, back to the boatyard. Water, water. I had to traipse up and down into the galley with French bread, into the pilothouse with stuff for the refrigerator. I drank water and left the other jugs in the car. It was still early afternoon.
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I threw a chicken carcass into a pot with six cups of water and 3 bullion cubes and brought it to a boil. I diced up green onion, mushrooms, and carrots. The carcass was removed and allowed to cool, fat and crud skimmed off the soup, rice and diced veggies added, and brought back to a slow boil. A large can of crushed tomatoes was added along with a large spoonful of Italian spice mix. The chicken carcass was deboned and the meat diced and added to the soup. When the rice was done the soup was done.
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It was now the end of the day. The soup made up for a skipped lunch and then a very colorful sunset ensued. The photo is of that sunset over the swamps of St. Marys.

Pain and Disappointment

12 May 2016 | St. Mary's, GA
Capn Andy/Hot and humid
It's time to write about pain. I made a mistake and stuck my thumb into the whirring trim router. Ouch! I didn't want to see what had happened, I guessed that my thumb would be half chopped off. Before any blood started flowing I jammed my hand into a nitrile glove. I didn't have my first aid kit available. It didn't hurt that bad, but I worked more slowly. It would probably hurt more later.
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I was trimming the corners of the lower part of the beam. It was the lower 2/3's of the beam and only the part that fit inside the port hull. After routing the exposed edges and cleaning them up with sandpaper I gave them a primer coat of unthickened epoxy. I had other areas to paint, which is a good idea so that you don't have leftover paint. Both the epoxy and two part LP paint set up after a while, so you have to use it all up.
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I was relaxing later at the communal kitchen area and got on the bike. I was looking down at how my front wheel was grinding over the boatyard gravel when I ran smack into a new boat that had been blocked up right near the kitchen area. I wasn't going fast at all, but it really rang my bell and I had to get off the bike and sit down. More pain.
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The Brits next door were continuing to work diligently on their paint job. They had started by removing everything from the boat surface. All the cleats, winches, stanchions, pad eyes, and even the molded in hatches were removed. All the surfaces were scraped, sanded, faired with compound, resanded, made as fair as can be. The alloy framed hatches were set up on a special table and the plastic panes removed, caulking removed, gaskets removed, new panes of new plastic were trimmed to shape with a straight router, and the hatches were reassembled, looking better than the new ones in the marine store.
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The tremendous amount of preparation work was necessary for the professionally sprayed paint job with very expensive paint. Then the painter let them know he couldn't do the paint job. He hadn't a window in his schedule unless they would wait a long time. The local boatyard painter who painted a monohull yacht right in front of their boat was obviously not an option. That paint job came out with grain and overspray in the finish. They then decided to do it themselves.
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DIY paint jobs can come out rivaling a professional spray painting. The technique is "roll and tip" using foam rollers and high quality brushes to fair any imperfections that the roller leaves behind.
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The Brits began rolling high build epoxy primer on their boat. It was a nice light tawny color, and it was obvious the surface had been prepared to perfection. Meanwhile I was laboring with my bloody thumb in the glove and trying to put as much epoxy on the exposed surfaces of the crossbeam as possible before I buried it in the hull where I couldn't epoxy it or paint it. My experiments with mohair nap sections of paint rollers didn't work out too well, the surface was lumpy and I wasn't going to sand off any epoxy, I wanted more on the beam, not less. I didn't care too much about cosmetics because the beam was out of sight, only visible to someone swimming under the crossdeck. I resorted to using the tried and true chip paint brushes and slopped on a couple coats of LP arctic white over the epoxy lumps.
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Then I heard sounds of consternation coming from next store. I went over. "See this?," he said, "When you sand down through these four coats of primer, the first 25% goes quickly, then it gets progressively harder to get it down where there is no orange peel. See here?", he pointed to a small area that was looking perfectly smooth, "It will take all day to make this one hull side look like that." He was asking for some sympathy. I took him over to my very rough beam, lumpy, drips of paint, and said, "This will make you feel better." He looked at it but didn't say anything.
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The photo is of the end of the beam, it is upside down.

Beam 3 Build Pt. I

10 May 2016 | St. Mary's, GA
Capn Andy/Hot and humid
The beam brackets were wire brushed to remove any loose paint, then painted with a rust preventative paint.
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The lumber for the new beam was sitting in the communal woodshop and I had already cut a few scarf joints when I tested the scarf jig. I decided to use those pieces of lumber to begin building the new #3 beam. The construction is of two horizontal layers of 2X6 followed by a layer of 2X4 rough sawn cedar, two pieces side by side, and then finally two layers of 2X6 again to top the beam off. It was an I-beam. The 2X6's which are nominally 5 1/2 inches wide were ripped to 5 inches wide.
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The first piece was an 8 foot 2X6 square on one end and with a scarf cut on the other. A cedar 2X4 was cut into two pieces, one 1/3 of the length and the other the remainder, about 5 1/2 feet. The original piece had a scarf cut at each end, so the two pieces were now glued side by side, on edge, to the 2X6. Self tapping deck screws with fender washers were used to help hold the pieces together.
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Next two more scarfed pieces were prepared, one was a 2X6 about 5 1/2 feet long with a scarf on one end. It would be laminated onto the 8 foot piece already in the beam. It is part of the bottom layer of the beam and would be buried in the hull, so it will have its corners rounded over, sanded, and painted before that piece of the beam is inserted into the hull. The second piece was another 2X4 8 foot cedar plank with scarfs on both ends. It was glued to the beam adding to the two existing 2X4's. The plan is to have the I of the I-beam complete almost to the midpoint of the beam and have the bottom layers of 2X6 complete within the hull. Then more 2X4's and 2X6's will be laminated on to complete the bottom and I of the I-beam all the way to the other end in the other hull. The parts that are inaccessible within the hull will be prefinished.
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The photo is of the beam end. The beam is laying on its face with the bottom two laminations facing away. The top two layers have yet to be laminated onto the beam. The two silver winches are single speed winches for halyards/running back stays.
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