Companionway Hatch, Construction, Part II

Mahogany Frame Dry-Fitted on the Most Level Place Available to me
Part II: Gluing-Up and Epoxy-Coating the Frame, the Shell, and the Planks

Whereas the first part of this four-part series on the construction of a companionway hatch for the Ericson 25 focused on the cutting of the new mahogany pieces from material purchased in a rough-sawn state, the second segment, to which we are now turning our attention, concerns the permanent assembly of these various wooden parts of the hatch by means of that all-important adhesive in contemporary boat-building and boat maintenance projects - epoxy.

Section 1: Sizing the Mahogany Planks

A preliminary task to the greater task of gluing the mahogany planks to the plywood shell was the sizing of the planks with regard to the parameters established by shell and the frame. You'll recall from Part I of this series, that, at this point, the frame had been joined merely by temporary screws in its four corners. Since I had not yet permanently joined the pieces of the frame, I still had the ability to make fine adjustments in terms of the size of the frame. Since I also had not yet determined how exactly I should fit the many planks into the confines of this space, I thought it wise to size the planks and determine the necessary spacing between the planks in advance of permanently joining the four pieces of the frame. In short, sizing the mahogany planks prior to gluing-up the frame gave me a little bit of leeway.
You'll remember in the first part of this series that I ripped the planks from a large piece of material that was originally 8/4 inches (2 inches) in thickness. You'll also remember that I had to run this rough-sawn material through the planer several times to get it to a workable condition. The planing of this piece resulted in a workable piece that was 1-7/8 inches in thickness. You'll recall as well that I ripped each plank to a thickness of 3/8 inch, and that I ripped as many of these planks as I possibly could from that piece of material. By the time I was finished, I had a stack of 19 planks that measured 32-1/2 inches (Length) x 1-7/8 inches (Width) x 3/8 inch (Depth). I also had one slightly over-sized remnant from the final rip. Fortunately, when I placed these planks one after another on top of the shell, I had just enough of them to have two extra planks as spares. In other words, of the 19 planks that I had available to me, I needed 17 of them. Even more fortunate for me was the fact that these 17 planks could be evenly spaced along the top of the shell. I had fully expected that I would not be so fortunate, and that I would need to trim each one of these planks in order for all of them to fit into this space just right. Sometimes you just get lucky, and given the time that I had already devoted to this project, it was a stroke of luck that was warmly welcomed.
Here's a view of the dry-fit layout from another angle. As you can see, the planks, at 32-1/2 inches in length, were longer than necessary. In the left of the picture they overlap the frame. I had intentionally over-sized the planks just so I would have plenty of material to work with when it came time to sizing them for the frame.
Since the plan I had formulated called for paying the seams with black polysulfide, I needed to leave 1/4 inch gaps between the ends of the planks and the frame. These gaps were the appropriate-sized gaps called for by the Boat-Life Company, the manufacturer of the black polysulfide that I planed to use for this project. The gaps, of course, allow for the expansion and contraction of the mahogany under different weather conditions.
After I had determined that the necessary length for the planks was 29-1/4 inches, I took the stack of 32-1/2 inch planks to the Makita miter saw and began cutting them to size.
I was left with a stack of 17 little scrap pieces of mahogany that were about 3-1/4 inches long. I figured I could eventually put these to good use as backing blocks for switches or terminal blocks or other such things as are necessary in marine electrical work.
As I laid out the properly sized pieces within the frame, I started to feel like I was really getting somewhere.
After lots of hard work, it finally looked like there was a new companionway hatch that was under construction, not just an odd assortment of pieces.
Starting with the center plank and working outwards I traced reference marks for each and every plank with a black Sharpie marker. I knew that when it came time to glue up these planks with epoxy I would need precise and highly-visible reference lines if I wanted to have any chance of keeping the planks evenly spaced and perfectly parallel.

Section 2: Gluing-Up the Frame

Having cut the mahogany planks to the appropriate size, I at last came to the point where I could permanently join the four pieces of the frame. This proved to be a more challenging task than I had anticipated, not because I had no experience in squaring-up frames, but because I was dealing with pieces (at least two pieces, that is) that were not straight, but curved. More accurately, I should say that these two pieces were indeed straight, but they arced upward, thus causing the top of the frame to lack a flat plane. With a flat surface on top of the frame, I could have used temporary diagonal stabilizers to square up the frame. These diagonal stabilizers would have served as the hypotenuses for the right angles of each corner of the frame. I had used diagonal stabilizers in the construction of garden gates on another project. That technique wouldn't work for this application.
As an alternative, I thought that mitre clamps or corner clamps or frame clamps might work. These are clamps that are formed in the shape of a right angle and are used for joining picture frames, and other such square objects. There were no mitre clamps that I could find, however, that would properly fit this companionway hatch frame.
Mitre Clamp
At a local hardware store, which has helpful employees who are experienced in marine hardware applications, an old-timer suggested to me what I thought was an excellent solution to the problem. He said that instead of trying to square-up the frame with clamps I should build a square jig on top of a piece of plywood. The jig, thus, would serve as a square frame for the mahogany frame during the glue-up process.

I returned home with every intention to approach the problem with the jig-on-plywood approach, but when I discovered that every decent-sized piece of scrap plywood that I had was just a little too small, I became exasperated, saying to myself that I wasn't going to go buy and entire sheet of plywood for this temporary purpose.

Back at the hardware store, I walked the aisles determined to find some piece of hardware that would help me get out of this quagmire. Finally, it hit me. Why not use angle brackets in each corner? With large angle brackets in hand I could use the clamps to secure each bracket in each corner of the frame. I explained my idea to the old-timer, and he thought it would be a sound alternative to the problem.

The four-inch angle brackets ended up being an inexpensive and easy means for squaring-up the mahogany frame. When I dry-fitted the four pieces of the frame together in this way, I found that the frame was held firmly square. I checked all corners with the carpenter's square, and I checked the diagonal measurements
just to be sure.
Angle bracket method that I eventually used to square-up the frame
When the time, at last, came for me to glue-up the frame, I decided that, in lieu of using epoxy, I would use a waterproof, polyurethane glue, Gorilla Glue, to be exact. There are two reasons why I chose to use Gorilla Glue rather than epoxy for the glue-up of the joints. For one thing, I was working indoors. Secondly, I would using stainless steel screws in these joints in addition to the Gorilla Glue. My thinking was that the Gorilla Glue plus the fasteners would make the joints just as strong, if not stronger than epoxy joints by themselves.
I had used Gorilla Glue before this time for other projects, so this glue-up of the frame went quickly once I had figured out the above-described technique for keeping the frame perfectly square. Note the level in the picture below. I knew that the hardwood floor was perfectly level. That's why I was doing this glue up in this indoor location. I, of course, wanted to recheck for level after I had applied the protective cardboard layer between the floor and the frame.
Same side of the frame, different view.
The opposite side of the frame.
Section 3: Epoxy-Coating the Shell

The next stage of this lengthy, companionway-hatch construction project involved the coating of the plywood shell with two coats of epoxy on both sides and about four coats of epoxy on the end-grain of the plywood. You'll recall from Part I of this series that I constructed the shell by laminating two, 1/8 inch pieces of luan with MAS brand F.L.A.G (Filleting, Laminating, and Gluing) Epoxy. Luan, as you'll remember, is often called Philippine mahogany because of its orange-red color and grain pattern that occasionally resembles mahogany. Since, however, it belongs not to the mahogany family - the family, Meliaceae - but to a family of trees native to southeast Asia - the family, Shorea - it is not a true mahogany. Nevertheless, it is often used as an underlayment for vinyl floors in kitchens on account of its mildly rot-resistant characteristics. Even though this luan shell would not, according to my plan, be directly exposed to the elements, I nevertheless decided that it would be prudent it give it a thorough coating of epoxy, simply because it would be in a marine environment.
Luan Shell with First Coat of Epoxy
For this epoxy-coating work I used RAKA Epoxy, specifically the 127 (Low-Viscosity) Resin and the 350 (Non-Blush) Hardener. Since the 127 Resin is a low-viscosity formula, it is ideal for saturating wood. The 350 Hardener causes the epoxy mixture to set-up pretty quickly, especially in hot weather. To me, this is a good thing when saturating wood. I can usually come back and apply the second coat after two hours, and then sand the whole thing about 24 hours later. RAKA might look like a cheap, generic brand, but there are plenty of people, professionals included who swear by it. MAS Epoxy is much cheaper than West System Epoxy, but RAKA is much cheaper than MAS. I should note that I now buy all my epoxy, my epoxy-fillers (such as wood flour and colloidal silica), and my cloth from RAKA. They say on their simple, no-frills website that they answer the phone if you call, and guess what . . . it's true.
RAKA Epoxy in the cockpit of my Ericson 25 for another project
In my experience, the first coat of epoxy on plywood (whether luan or exterior-grade southern yellow pine) is quickly absorbed and leaves very little sheen.
The second coat, on the other hand, usually results in mostly-glossy, but not entirely glossy surface (since there are usually some areas here and there that absorb the epoxy more readily than others.
Another picture of the shell with its second coat of epoxy.
Epoxy-work essentials. I eventually quit buying the 25 packs of gloves and instead bought boxes of 100, as I worked on epoxy-coating the shell and other pieces of plywood for other boat-related projects (which I will discuss in other articles). I reused the cups, brushes, and mixers as many times as possible. Gloves, obviously, don't fall into the same category.
The next day, I turned the shell over and gave the underside its first coat of epoxy.
Two hours later, I came back and laid down the second coat.
One day later, after the epoxy and cured, I carried the shell out to the yard and started to sand away the sheen, so that when it came time to glue-up the mahogany planks they would more readily adhere to the plywood shell.
It was slow-going, even with 60-grit sandpaper discs. I worked methodically, hitting one quadrant at a time.
Even though the epoxy, at this point, had reached a full-cure state (according to the RAKA website), I still approached this project wisely - wearing gloves, a long-sleeve shirt, a respirator, a face-shield, and . . . earphones. It was over 90 degrees and the Carolina Lowcountry humidity was merciless, but I figured I'd rather be soaked with sweat than covered with epoxy dust, both inside and out.
One side down, one to go.
It was a little strange sanding the underside, given the curvature of the shell. Clamps were a must.
Despite all the clamping and all the work with the orbital sander, this shell never lost any of its shape.
Section 4: Routing and Sanding the Frame and Planks

From a distance, it might have seemed, at this point in the companionway hatch construction project, that the mahogany frame and the mahogany planks were beautiful creations, but up-close they were, in fact, hideous
creatures that had not yet been fully-tamed and well-groomed for faithful service.
The frame was the worse of the two.
And the worst parts of the various parts of the frame were the lap joints.
The joints were not as tight as they should have been, and there were some unresolved problems in terms of how make the straight lines of the side pieces meet the curved lines of the other pieces at the corners. The small gaps in some of the joints were entirely the result of slight variations in the cuts that I had made with the jigsaw. Blade-walking, as I said in Part I of this article, was an ever-present issue when sawing this 1.25 inch mahogany with the jigsaw. As far as the problem of the straight lines not joining the curved lines in the corners . . . well, that was just an outgrowth of the curved shape of the hatch itself, and like always when it comes to marine carpentry, I would just have to find a way to work with these curves.
My first attempt to smooth the lines was a miserable failure. For some reason I thought I could this with a quarter-sheet sander with 80 grit paper. Mahogany is tough, and if you really want to make any headway with it, you have to use 40 grit paper. That's been my experience.
Frankly, what I was trying to avoid was having to use a router on these lines. I had invested a lot of time, effort, and money to get the frame to this point, and I was a little scared of screwing it up with a mistake with the router.
To get my courage up, I decided to flip the frame over and focus on a less-conspicuous area - the underside of the side rail. I had wanted to sand these sharp lines anyway, so why not just hit them with the round-over bit on the router? That was my thinking. As soon as I made that first pass, I was pleased with the results. I was so pleased, that I grabbed the router again and stood in the space between the frame and the porch and routed in inside edge of the side rail.
Below you see a picture of the side rail with the underside edges having been routed on both sides (inside and out).
As far as the drip line was concerned, I had to hit that with the sander. The odd angles made the use of the router out of the question.
When I had finished doing as much as I could to the underside of the frame, I flipped it back over to the top side and carefully began rounding over the edges with the router. I remained unsure about the corners, so with each pass of the router, I lifted the tool off of the material just before I reached the corner. The picture below illustrates this well.
After taking a break and thinking about it a little more, I picked up the router and hit the corners of the frame. I was immediately pleased with the results. The curved lines and the straight lines joined each other in the corners just right.
Satisfied with the frame, I turned my attention to the mahogany planks. You'll recall from Part I of this article, that I ripped these 3/8 inch planks from a piece of material that was 1-7/8 inch thick. On account of these rips, each one of these planks had marks from the blade of the table saw.
After I decided which side of each of the planks would be the finished side, I began sanding each of the 18 planks with 40-grit paper. Even with this type of paper it still took a long time to get rid of all those saw marks. I, of course, didn't bother to sand the underside of the planks, By leaving the saw marks in the wood, I figured I would increase the chances of good adhesion when it came time to glue-up the planks to the plywood shell with epoxy.
Section 5: Epoxy-Coating the Frame and Planks

The next step I took in this companionway hatch construction project was to epoxy-coat the frame and the planks. Since this was mahogany, and since mahogany is not as rot-resistant as teak, I thought it would be smart to epoxy-coat the frame and the planks as a precursor to varnishing the hatch when the construction process was complete. Why exactly I epoxy-coated the entire frame, instead of just the underside, I do not know. Maybe the summer heat had gotten to me. I knew that epoxy is not UV resistant and that it has a tendency to fail when coated with varnish, instead of paint. Nevertheless, I still epoxy-coated the whole thing, not just once, but twice. Fortunately, when I epoxy-coated the planks, I only did the underside, not the top. The only reason why I left the topside uncoated was because I wanted to wait on the epoxy until I had glued the planks to the plywood shell and payed the seams with black polysulfide.
Another mistake that I made in this stage of the game was the filling of the counter-sunk screw holes in each corner of the frame not with a mahogany plug, but with Elmer's Red-Oak wood-filler. The store I visited did not have mahogany wood-filler and the red oak looked like a good match. Bad move.
Here's a picture of one of the other corners of the frame. The wood filler was tolerable prior to the application of the epoxy.
And here's a shot from afar of the first coat of epoxy.
This picture below of the corner of the frame should give you some idea of just how bad the red oak wood filler looked after I applied the first coat of epoxy. Each corner had an orange circle in it. There were also orange lines in a couple of the joints where I had tried to correct a few mistakes I had made with the jig saw.
Second coat of epoxy on the topside of the frame and second coat on the underside of the planks.
Underside of the frame just prior to the first coat of epoxy.
First coat of epoxy on the underside.
Second coat of epoxy two hours later.
The next day I carried everything out to the yard to sand the epoxy. I covered the work table with a white sheet in order to protect the unfinished sides of the planks from scratches. These unfinished sides were, of course, the best sides, the ones that would eventually be visible on the outside of the hatch.
Even though they were small, the planks required quite a bit of sanding.
I had to rough-up the sides of the planks as well. These sides would form the sides of the seams between the planks and I wanted to give the black polysulfide surface with good teeth in it.
The eighteen epoxy-coated planks at the end of the sanding process.
The frame was a royal pain to sand. I started out trying to do it on the work table in the yard. The problem was hard to clamp it in place.
I moved to the edge of the porch, where I could clamp the frame on the edge of the wooden deck.
Clamping the frame might have been a pain, but it was not as big of a pain as the sanding itself. There were many nooks and corners that required work with the hand.
When, at last, I was satisfied with the sanding job, I cleaned up the dust with acetone. I wanted to get in good shape before passing it off to a buddy of mine who has a custom woodworking business. Shortly before this time I had mentioned to him how displeased I was with my wood-filler work in the joints of the frame. He told me that if he were doing this job he would just put Dutchmen in each of the corners. I told him I didn't know what Dutchmen were. He said they were thin pieces of wood that covered the entire joint. The only trick was that you had to cut out a 1/8 inch bed in each corner for these Dutchmen to lie flat. I told him that what he was describing was beyond my ability. He said that I shouldn't worry about it. All I needed to do was hand the frame over to his assistant at the shop, and he'd make sure that assistant took care of it for me during some time between jobs. About two weeks later I got the frame back. The Dutchmen were beautiful. Did I buy my custom woodworking buddy a case of beer for getting this job taken care of for me? You betcha.
I should mention that it was soon after I received the frame with the Dutchmen in it that I decided to sand off all the epoxy on the outside of the frame. The assistant who had installed the Dutchmen had sanded off all the epoxy from the corners of the frame. To keep the finish of the frame consistent, I would need to apply two coats of epoxy to the corners of the frame and then sand them to the same point as the rest of the frame. Not wanting to do this, and remembering well that I never should have epoxy-coated the exterior of the frame to being with, I decided to sand off all the epoxy from the exterior of the frame. This took a lot of time, and I was so irritated at myself for having to engage in the task that I was up to taking any pictures of it. I can only comfort myself that I learned a lot from my mistake and that my lesson would have been much harder if I had not taken the time to remove the epoxy prior to laying down the varnish.

Section 6: Gluing up the Planks

The next challenge that awaited me in the construction of this new hatch was the gluing of the planks to the shell. As you can tell from the picture below, as a first step in this gluing-up process, I pulled out the mold that I had used for laminating the two pieces of plywood for the shell. That was the easy part, but a puzzle remained. "How can I apply clamping pressure to the planks, if I can only clamp the end of the planks near the edge of the table?" This was a one question I asked myself.
Another question that I asked myself was this: "Should I try to glue-up all the planks at one time, or should I only glue-up a few at a time?"
I did a couple of dry-fit experiments to see what might work. First I tried dumbbells. I figured these would do the trick. Wrong. I could see gaps here and there along the edges of the plank.
Then I decided to bring out the cauls, i.e., the curved pieces of wood that I had used when I laminated the two pieces of plywood together to make the shell.
These didn't do a very good job either. Trying to hold down eighteen different planks was more difficult than holding down a single piece of plywood. Whenever I tried to apply weight to the top of the cauls or tried to clamp the cauls, the planks would shift away from true.
Then, and idea came to me . . . "What if I used a piece of 2x4 as a caul of sorts?"
When I experimented with the 2x4 technique, I found that I could hold a plank very still and could apply good clamping pressure as long as I applied a clamp to each end.
I decided that the maximum number of planks that I could manage to glue-up at one time was nine. Therefore, I cut nine-pieces of 2x4s to the appropriate length and clamped it all down with eighteen total clamps. For the glue-up, I used MAS F.L.A.G. Epoxy and Medium Hardener with a lot of wood flour and colloidal silica mixed in for flexibility and strength. This epoxy mixture has a much longer open time and cure time than the RAKA brand epoxy that I described above. I've thickened up the RAKA Low Viscosity Resin and Non-Blush Hardener with flour and silica for gluing purposes, but if I'd tried to use this RAKA epoxy mixture for this particular job, I would have run out of time. It was not easy keeping the planks true while applying the clamping pressure. They kept wanting to move as I tightened the clamps. I had to make many fine adjustments and double-check myself as I moved from one plank to the next, outward from the center.
You probably noticed the clumps of epoxy on the plastic, which surrounds the edges of the mold. After I got everything clamped down, I spent a lot of time picking out the excess epoxy that squeezed out from the sides of the planks. I used a long and narrow screwdriver for this job. If I had not removed the epoxy, at this time, I'm not sure that I would have ever gotten it out of those seams.
Below you can see the narrow corridors out of which I had to extract the epoxy from the seams.
It wasn't as simple as dragging the tip of the screwdriver from one end to the next. If I had done that, I just would have caused it to get gooped-up in the narrow space. No, I had to pick this stuff out one little scoop at a time. Even doing it this way, I had to go back and hit a lot of spots again.
Another shot, this one from the other side of the shell.
Yet another shot, this one from one of the corners.
I let the initial glue-up job sit in its clamped state for about a week while I worked on other projects. I wanted to make sure the epoxy and fully cured before I took the clamping pressure off of the planks.
I was pretty pleased with the results. Fortunately, I had paid close attention during the glue-up process not to get any globs of epoxy on the tops of the planks. If I had, I probably would not have gotten those 2x4s off of them. As you can see below, I did indeed get a few touch marks on the planks from picking them up with my gloved hands and putting them in place during the glue-up. These areas did result in some minor problems as I was removing the 2x4s, but nothing major.
You can see a few remnants of the 2x4s on a few of the planks below.
You might have noticed the numbers on the plastic. I placed these numbers there so that I would lay the planks in the order in which I had dry-fitted them. During the dry-fitting process, I arranged the planks so that their grain patterns were as harmonious and consistent as possible. After all, I had ripped all of these planks, side-by-side, from the same piece of material.

If you look closely at the picture below, you'll see a mistake that I made during the laying of the planks. Do you see the number 13 on the plastic? Look up at the plank above it. Do you see the number 13 there? Do you also see how that plank is darker than all the others and that it is the only one with a number on it? I laid this one with the bottom side up. This was the side that I had epoxied, and it was also the side I used for marking the numbers. This error only goes to show how caught-up I was in the gluing-up process. I should note that eventually I would sand off this epoxy, and the plank would end up looking like all the others.
I glued-up all the rest of the planks at the same time using the same method that I used for the planks in the center.
Once again, I spend a lot of time digging out the excess epoxy from the seams.
Clean seams would mean that black polysulfide could be 3/8 inches deep. This was the depth recommended by the manufacturer, Life-Caulk.
A view from the other side.
More clean seams.
A detailed shot.
Notice the precarious placement of the sawhorses. This was the only way I could get the clamps on the ends of the mold.
Section 7: Gluing and Filleting the Shell to the Frame

I allowed the clamps on the ends of the shell to remain in place for about a week, and then, confident that a full cure had been achieved, I removed them and moved forward with the sanding of the planks as a preliminary step to gluing the shell to the frame.
In the picture below you can see well the plank that I glued upside down. It's the dark one.
I started out by sanding the tops of the planks with the quarter-sheet sander.
I spent most of my time, however, sanding the seams. I wanted to make sure that any remnants of cured epoxy were scuffed-up. This would allow the black polysulfide to adhere more tenaciously.
I used many a piece of sandpaper to achieve the desired results.
Not a fun part of the project, but then again you'd have to be moron to have a good time sanding epoxy by hand.
When I finally finished the sanding, I dry-fitted the shell-plank assembly into the frame.
I was pleased to see that it fit into the frame without binding and without leaving any big gaps.
There was just enough wiggle-room to allow for the expansion and contraction of the material.
For the glue-up, I once again used MAS F.L.A.G. Epoxy and Medium Hardener with a mixture of wood flour and colloidal silica.
I made sure that the entire rabbet was coated with a healthy layer of this thickened epoxy so that I would get good squeeze from the joints when I clamped it all down.
If I remember correctly, I mixed about 9 ounces of epoxy for this application, since I also planned to do fillets on the underside after I finished the glue-up.
I set the shell-plank assembly into the frame and clamped it down.
I didn't clamp the ends, because I couldn't get a good grip in that area.
I avoided getting epoxy on the clamp pads, but it wasn't easy.
Just as was the case with the gluing-up of the planks, I went back and picked out any excess epoxy I could find, so that the joints or seams would be as deep and as epoxy-free as possible for the black polysulfide.
I put fillets around all four sides of the underside of the hatch to increase its strength.
The fillets weren't pretty in the corners. It would later take a good bit of sanding to get them cleaned up.
In general, though, the fillets turned out nicely, even though I was working upside down.
This ends the second part of a four-part series on my construction of a new companionway hatch for the Ericson 25. In the next part of this article I will focus on my paying of the seams with black polysulfide.

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