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Monday, January 19, 2015

Kingfisher Drift Boat - Prepping the Hull for Painting

It's time to get ready to paint the hull, I've done about all I can do on the interior of the boat and it's time to work on the outside for a while, This will entail flipping the boat upside down to work on. To get ready for painting the hull I had do do quite a bit of work prior to getting it done.


Getting a little ahead of myself. Here's the hull after it was painted.

The critical path went something like this
  1. Flip the Boat over
  2. Sand or use a cabinet scrapper to prep the bottom of the gunnels
  3. Flow coat the underneath side of the gunnels once they are prepped.
  4. Run a fillet of epoxy peanut butter at the junction of the gunnels to the sides.
  5. Run another flow coat of epoxy on the underside of the gunnels and coat the fillet
  6. Sand and flow coat the rounded transom with it's last coat of epoxy
  7. Finish sand and the underside of the gunnel, the sides and the rounded transom progressively to 220 grit.
  8. Mask off the gunnels and the rounded transom to get ready for painting the hull.

Flipping the Boat

I enlisted the help of three friends to flip the boat over. It has been residing right side up on a 4' x 10' table with rolling casters. The first task was getting the boat on the floor of the shop. I worked the boat to one end of the table. Imagine launching a boat from a trailer. Once I got the stern on the floor we just lifted the bow and slid the table out from under the boat. I had furniture blankets on the floor. The gunnels are coated with at least two coats of epoxy but I still wanted to have blankets under anything on the boat that contacted the floor. The steps went sort of like this.
  • Place furniture blankets on the floor in position so that as the boat is lifted up on one side and supported on one gunnel (half-way flipped) the blankets are under the spots of the center section of the gunnel. Pretty much in the center of the boat at the oar locks.
  • I also placed furniture blankets that are folded up in multiple layers under the stem and transom so that when it is flipped it is cushioned under these areas.
  • Two people are on one side of the boat and two are on the other.
  • The boat is lifted by two people so it is resting on one gunnel, basically half flipped. The other two people help support the boat in the vertical position.
  • It is then tilted over to the upside down position and supported by the two people on the other side of the boat.
  • Once the boat is flipped and is resting on the floor, lift the bow up and slide extended sawhorses, about 5 1/2' long, underneath so the bow is supported by both gunnels. Cover the tops of the sawhorses with padded materials. I used old towels.
  • Repeat the same procedure for the stern of the boat.
  • The boat should now be flipped upside down and resting on the padded extended sawhorse.
  • Ready to go to work.

Prepping the Gunnels and Rounded Transom for Flow Coating


One problem when flow coating the gunnels when the boat is right side up, is that it is almost impossible not to have drips or runs of epoxy on the underneath side of the gunnels. I found that the best approach is to use fast set hardener in small batches and tend it until you can't mess with it anymore. Even doing this I had some runs and drips. The best way of getting rid of these drips and runs on the underneath side of the gunnels is to use a cabinet scrapper. The scrapper removes the material you need to remove quickly and efficiently. Once the runs and drips are knocked down I then final sanded them by hand. I used 120 grit followed by 150 grit followed by 220 grit. They turned out pretty darned nice. Note: Remember to use cabinet scrappers to do the dirty work.

I finish sanded the rounded transom next to get it ready for its last flow coat of epoxy. Most of the rounded transom will not get painted and the mahogany plywood will be varnished.


This photo shows the detailed and sanded underneath side of the gunnels and the epoxy fillet at the junction of the gunnels to the sides.

Flow Coating the Gunnels and Rounded Transom

Once the underneath side of the gunnels were sanded it was time to flow coat them. I masked off the gunnels at the center of the 1/4" round over all around the boat. I didn't want the epoxy to run back down the face of the gunnels. I also flow coated the rounded transom. This is basically the last of the flow coating of epoxy on the entire boat. Wow, it's been a long time coming.

Sanding the Sides, Gunnels and Rounded Transom

Now that the flow coating was completed on the hull it was time to finish sand the entire exterior of the boat. I used a random orbital sander and sanded the sides to 220 grit. Being that the rounded transom is curved I used a flexible pad and hand sanded it down to 220 grit. I hand sanded the underneath side of the gunnels to 220 grit.

Clean Up and Masking

The last steps were to vacuum all the surfaces and then wipe the surfaces down with acetone and then start masking. Once the surfaces were vacuumed, I used the two rag method for prepping the surfaces. One rag is used to wipe down the surface and a clean rag follows.

Now it's masking time. I used 1/4" wide green masking tape that is used in auto body shops to mask the line that I will paint to. Once the 1/4' tape is laid down I use a masking machine with 3M 3/4" blue tape and 12" wide masking paper that comes on a roll. I taped off about 12" from the 1/4" green tape along the gunnels, the rounded transom and the Linex material that wraps up the sides about 4".

After the sides were masked to isolate the portion of the boat to be painted I checked to see that the tape was set tight at the paint line.


You can see the green 1/4" wide masking tape at the line to be painted. It is taped to the Linex that runs 4" up the sides. I then used a masking machine to finish up.

Next Up - Painting

Monday, January 12, 2015

Kingfisher Drift Boat Build - Hatch Trim & Hatches

I enjoyed the holidays with my family and got back on the build with installing the hatch trim and making the hatches.


There are 4 deck hatches and two pedestal hatches. The 4 deck hatches access the dry storage boxes. There are dry boxes on each side, each with two access hatches.

I first had to make backing that glues underneath the deck plywood along the edges. This reinforces the decks and gives up something to attach the hinge screws. The hatch backing is made with strips of 1/4" Okoume plywood that are about 2" wide. I made the strips and cut them to length. I had to make special strips that were about 5/8" wide that butted to the deck rail that runs lengthwise under the deck. Once these were cut I set them aside to flow coat with epoxy before gluing them in place under the deck and around the hatch opening.

I them had to make the hatch trims. These are strips of white oak that are 1/4" thick  x 1 1/4" wide. I made a list of the sizes required for each hatch opening and cut them approximately 2" longer than the finish length. Once all the pieces were cut to length I had to cut a saw kerf on one side near the top edge create a slot to install hatch coaming. Hatch coaming is a type of gasket seal. The saw kerf is about 3/32" deep x 3/32" wide. It is cut on one edge about 5/32" from the top edge. I set up fingerboards on my table saw and cut the saw kerf on each piece. I then set them on a table to flow coat them with epoxy.


Here is a piece of the hatch trim. It is 1/4" x 1 1/4". The saw kerf is on the top right.

Once they were flow coated and finish sanded it was time to install them. The hatch trim pieces fit inside the hatch openings. The bottom of the hatch trims are set flush with the bottom of the hatch backing and stick up above the deck about 3/4". The pieces are glued in place with thickened epoxy. Once the pieces are glued in place. (4 for each hatch) I cut sticks that were wedged inside to hold them in place. I did this for the 4 deck hatch openings and the two pedestal hatch openings.


Here's a photo of the hatch trim installed on the front pedestal. It sticks proud of the opening by about 3/4". The back is flush with the back side of the opening. It was glued into the opening with thickened epoxy.


This photo shows the hatch trim installed at one of the dry box openings. The opening has been filleted with epoxy peanut butter to seal the deck opening.


Hatches

I next had to make the hatches. They are constructed with white oak trim that has a rabbit to accept a 1/4" Okoume plywood panel. The stock was milled to 5/8" x 3/4". I milled a 5/32" x 5/32" rabbit on one edge to accept the panel. The hatches must be large enough to fit the weatherstripping. The next step was to mitre the pieces for each hatch. I then cut the plywood panel to size.
I glued the miters and the rabbet to accept the panel with thickened epoxy. I clamped the assembly all at once.




Here is one of the pedestal hatches. This is the back side. It looks sort of like a tray.


Here is the front side of he same pedestal hatch. It has been flow coated with epoxy and sanded. It will get one more flow coat of epoxy and then multiple coats of varnish.

Kingfisher Drift Boat Build. - Installing the Deck Trim and the Rod Rack Trim

My last post for the Kingfisher drift boat build was on December 12th. It's now January 10th. What the heck have I been doing for the last month. Well, I've mainly been taking care of details. Prior to the holidays  I installed the wood plugs at the deck and the deck trim. The progression was;
  • Plugging the screw holes in the decks once they were installed.
  • Making the trim 
  • Steam bending the front deck trim
  • Installing the trim at the decks
  • Installing the trim at the rod holder
  • Flow coating the deck trim with epoxy

Installing the wood plugs in the main deck

The main deck which curves around at the front is screwed to the framework with #8 x 1" silicon bronze screws. There are about 32 of them. I used a 3/8" countersink bit to allow for the wood plug. The decks are constructed with 1/4" Okoume mahogany plywood so getting the depth of the countersink right is a little tricky. Too deep and the screw has nothing to secure or not deep enough and you can't install the plugs. It's best to play around with a piece of scrap to get it right. 

I made the plugs with a 3/8" plug cutter and a drill press. I made a bunch of them. Drill a mahogany board and then rip the board on a bandsaw and you've got a bunch of plugs. One tip is to install the clean up any epoxy that oozes up through the holes when you attach the deck. If the epoxy ooze is allowed to set up you will not longer have a 3/8" diameter hole and the 3/8" diameter plug won't fit. I had some of these and it is a pain to get the holes cleaned up. I used a 3/8" diameter brad point drill bit and carefully twisted it by hand to clean up the hole. Don't do it in a drill or you'll be sorry. Again, I found this out.


The photo above shows the glued down deck. The edge trim has not been installed yet. The plugs are installed and finish sanded. You can also see the epoxy fillet at the deck where it joins the sides.

I used Tightbond Waterproof glue to glue in the plugs. Once the glue set up, I used a Japanese hand saw designed to flush cut plugs to cut the plugs off. Once the plugs were cut off I used a 120 grit orbital disc to sand the plugs flush. Be careful not to sand in one spot or you can possibly sand through the flow coats of epoxy on the deck. This is a big problem so don't do it. Once the plugs are flat, final sand the deck progressively to 220 grit.

Installing the deck trims

The next step was to make the deck trims and the trim for the rod rack. I made the deck trim out of  kiln dried white oak. This is fine for the straight pieces but difficult for the curved piece that is placed in front. I made finished stock that was 11/16" x 7/8" for the deck trim and 3/4" x 3/4" for the rod trim. Once the stock was made I used a carbide tipped dado blade with a spacer to make dados in the stock that were about 1/64" wider than 1/4". This dado goes over the 1/4" plywood that is flow coated on each side. The flow coating makes the plywood thicker than 1/4".


This photo shows the curved deck trim installed and epoxied in place. The piece is bent to a radius of about 19". 

The process of making the rounded deck trim involves steam bending and making a form to do so. You also need extra stock as bending a piece like this will take just the right piece and you don't know if it is until you attempt to bend it and clamp it to the form. I broke 3 pieces before I finally got one to bend to the radius. One trick is to make the dado deeper. I broke the first 3 pieces when the dado was 5/16" deep and the first one I tried with a dado that was 7/16" worked.  Was it the grain or the depth of the dado? Not sure but it worked.

I cut the pieces to size, ran the dado and then rounded the top and bottom edges that would be facing the deck, (the side with the dado) with a 1/4" round over bit in a router table.. This would have been impossible to round over once it was installed. (I rounded the other edges once it was glued into place). I then placed the wood piece in a steam tube and steamed it for about 1 1/2 hours. Once it was steamed I clamped it to the form and let it sit clamped up in the form for 24 hours. Like I said this took all day as I broke the first 3 trying to bend them.

I took the piece out of the form the next day and it sprung back quite a bit. I was able to dry fit it onto the curved plywood deck and clamp it in place. I took it out and then coated the inside of the dado with thickened epoxy. More of a runny mayonnaise consistency. I coated it a second time and installed it with 3 way edge clamps.

Once this piece set up, I glued the straight pieces on that run lengthwise to the stern, I used one long piece that was about 7 feet long and a shorter piece that was about 2 feet long on each side. I fit the rear one first and scribed it to the sides at the rear. I fit the longer one between the front curved section and the rear piece. This was very easy. I held this in place with package tape as the 3 way edge clamps would not fit because of the rod rack. I glued on the rod tray trim at the same time.

Flow Coating the Deck Trim


Once the epoxy had set up that glued the deck trim and the rod shelf trim in place I finish sanded the pieces progressively to 220 grit. I then coated the trim with 2 coats of epoxy. I used Raka UV Inhibited Resin mixed with Raka UV Inhibited Fast Set Hardener. This allows you to tend the epoxy as it sets up and eliminate most if not all of the runs, sags and drips. This is good to remember when flow coating anything that is a vertical or sloping surface.

Next Up - Casting Deck

This was all accomplished before the Holidays and I got started back up with installing the front casting deck.