Saturday, April 7, 2018

Stain & Epoxy — So Far, So Good...

The System Three Silvertip epoxy seems to be adhering on to the stained wood just fine.

Here's how it looked after the first coat:

Again, the stain I used was Minwax Gel Stain. I applied one coat, then let it dry for five days. I applied it pretty heavily, so that there would be enough thickness to withstand a light sanding without penetrating the epoxy and marring the stain.

I let the epoxy cure for about 2 days, then sanded it lightly, and cleaned the surface with a small amount of denatured alcohol. 

Then, I applied a second coat. Once again,  I applied it pretty heavily with a foam brush. Once that cured, I sanded it a little more aggressively to even out the surface, making sure not to sand all the way through the epoxy. I'm currently in the process of sanding the rest of the frame, in preparation for the third coat of epoxy.

Sanding the second coat

Sunday, March 25, 2018

To Stain, or Not to Stain? THAT is the Question.

So, the epoxy encapsulating process on the forward (hidden) face of Frame #4 went pretty smoothly:

The problem was, the particular piece of mahogany I had selected as the dash beam developed a really high-contrast, "striped" look to the grain when coated with epoxy.

While maybe this didn't look "bad," it was a bit of a leap from the look I wanted. The highlights in the grain were almost the same brightness as the epoxy-coated cherry inlay. It was all just more visually distracting than I wanted it to be.

After all the work I had put into the dash beam, I was not inclined to build a new one from a tighter-grained piece of wood unless it became absolutely necessary. So, I began to consider using a stain for the aft face, (the actual dashboard), in order to darken the piece overall — especially the highlights.

Another builder had some success with the Minwax Express Color water-based stains. I'd bought a tube of it several years ago, based on his recommendation. There was still a bit left, so I experimented on some scrap mahogany to see how it would look.

One coat, and two coats of Minwax Express Color "Mahogany" compared to my epoxy-coated dash beam.
After a lot of thought, and more overthought, I finally decided to go with two coats of the Minwax Express Color stain in the "mahogany" color. Since my tube was a few years old, I wanted to get a new one to use on my actual dashboard. There was a problem:

It was the ONE color of the stuff that was out-of-stock at my local Ace Hardware. At Home Depot, where I'd bought it originally, the Express Color product was NOWHERE to be seen. Lowes? Hey... they compete with Home Depot, so they didn't have it either.

Back to the drawing board.

A little online searching led me to this article, Epoxy Adhesion Over Stains on

In a nutshell, the article covered adhesion tests of West System epoxy to wood treated with a variety of stains. They tested stains dried for 24 hours and for 4 days. Minwax Gel Stain was one of several that passed BOTH tests. So, I decided to try it.

I tested both the "Mahogany" color and the "Red Elm" color on some scrap mahogany. The "Red Elm" stain produced a darker color, with a stronger red hue on my test piece. It also seemed to darken the highlights in the grain proportionately more than the "Mahogany" stain.

One coat each of "Mahogany" stain (top) and "Red Elm" stain (bottom) on my test piece of mahogany.
By this point, my impatience kicked in. I was tired of thinking about it, and ready to just do it. I chose to go with one coat of the "Red Elm" color.


DURING. A "liberal amount of stain, evenly applied."

AFTER. Per the instructions, I let the stain sit for 3 minutes, then wiped away the excess.
The end result was darker and "browner" than my test piece. However, the stain did indeed minimize the high contrast "stripes." The color is acceptable to me. I would've preferred more red than brown... but I'm not going to mess with it any further. It does offset the cherry inlay MUCH better than the epoxy-only side.

Now, I'm going to give it at least 4 days to dry. Then, I'm going to hope and pray that System Three Silvertip epoxy adheres to it as well as the West System epoxy in the tests.

Shims for the keel

LAST TIME, on "Keel: Truth and Theory" ...

This little gap on the side will get a shim, also. Is that a hairline crack I see?
Why, yes. Yes, that was indeed a hairline crack I saw. 

It was a couple of inches long, too. I decided that just wasn't acceptable, so I employed my new router to mill away the area with the crack. It was surprisingly easy. I kept the depth of the router bit just barely shy of the seam, to avoid cutting into the underlying piece of wood. I finished the remainder with sandpaper and chisel. Now, it looks like this:

Here, you can also see the narrow shim, grafted onto the left side of the board.

Here are some other before & after photos of the other shimmed areas:

BEFORE. This is the area at the butt joint.
BEFORE. This is the starboard aft of the keel.


There's still a little more sanding and preparation work to get the keel ready to use. Soon, it will be time to build the construction form! Stay tuned...

Friday, March 2, 2018

The Slow Saga of Zip Frame #4 — part 10 (the end)

Today I reached a small but important milestone in the Zip project. 

With the dash beam now permanently attached to Frame #4, all structural work is finished on all of the frames.

I used System Three Silvertip epoxy, thickened with mahogany wood dust that I salvaged from sanding. Gussets are attached with 4 #8 3/4" bronze screws on each side. The solid stock is attached with 3 #10 1-3/4" bronze screws, countersunk into the vertical members of the frame.

The 3/8" bungs were cut from scrap mahogany cut off of the keel.

I trimmed the bungs with a big ol' traditional hand saw. Can you tell?

Sanding the bungs... It's starting to look better.

Friday, February 23, 2018

Keel: Truth and Theory

I cleaned up the edges of the keel, sanding & chiseling away the excess epoxy, to get a better look at the fitting of the laminated pieces. It'll work. There are some things I need to fix. There are some things I wish I'd done differently:

I wish I had cut ALL sides of each board with the table saw. Never assume the lumberyard edge is straight. There were some parts that were narrower than the rest of the board. Now, those places have caused uneven sides in the laminated section, and those spots need to be filled.

I wish I had planed the boards more. I needed the thickness of my laminated keel to be one inch. I also wanted to leave myself a little room for error. That's why I started getting nervous when the planed boards got as thin as 5/8". Unfortunately, leaving them at that thickness also meant that the surfaces didn't get planed as flat as they could have been. It turns out that, at 5/8" there was still plenty of thickness for me to plane them just a little more so that the surfaces would have been at least somewhat better. After lamination, the combined thickness is 1-1/2 inches. I was shooting for 1-1/4. So, I could have taken another 1/16" off each board, easily. The surface irregularities, though seemingly minor to the naked eye, left noticeable gaps when the pieces were combined. I knew that would happen, anyway.... but it could have been better.

For the very same reasons mentioned above, I wish I had taken the time to sand the surfaces of the boards after I'd planed them. I don't have a thickness planer. I have a general-purpose planer/jointer. It "gets the job done," but it's a lot to ask for one guy to get a nearly 10-foot board planed perfectly flat with one of these things. Just a little surface sanding would have knocked down some high spots, and improved the fitting.

Those are some lessons learned.

In most places, the fitting is fairly decent.

In some places, the fitting is better than in others.

This area on the starboard aft is definitely getting shimmed.

In some places, the fitting is not pretty. This gap in the seam will get filled with some more thickened epoxy. I'm also going to shim the gap seen at the bottom part of the photo.

This little gap on the side will get a shim, also. Is that a hairline crack I see?

Monday, February 19, 2018

The Slow Saga of Zip Frame #4 — part nine

I wanted to make all of the major cutouts in the dash beam long before the hull is built and flipped. It seems to me that it would be easier to do this work now, when I can lay the beam flat on a work bench, than when it's a vertical fixture in the hull.

And, since my dash has the 10 degree angle "built in" to the frame, I felt it would be easier to make these cutouts before attaching the dash beam to the rest of the frame.

Now, all those cutouts have been made.

3-1/4" cutout for the helm, plus marking the placement for a rocker switch.

I made the initial cuts for the rocker switch hole with a drill and a coping saw.

I enlarged the hole with my jig saw, and finished it with a wood file.

After some tedious and meticulous work with the file, the switch fits. I'll file it just a little more to accommodate a layer or two of epoxy.

The next steps for Frame #4 will be to sand away my placement markings and attach the dash beam to the rest of the frame.

Happy Monday to you! (Yes, it's a Monday, but we can make it a good one if we choose to.)

This is the day the Lord has made; let us rejoice and be glad in it.
— Psalm 118:24

Sunday, February 18, 2018

3/4 of a keel

Lamination work on the keel has begun.

I started with the big 4" wide chunk of mahogany, mentioned in the last post. It was 4" wide, 2" thick, and 9' 10" long.

The plan was to re-saw this board into 3 smaller boards, each approximately 1/2" thick. I would then (a) cut a short 3' section off of one of these boards, and butt-join it to one of the longer ones. I'd then (b) take the longer leftover cut, and use it to back the butt joint.

This would leave me 3/4 of a keel, with the thicker section on the aft portion. Since the forward section would temporarily be thinner, it should (c) be easier to bend, as needed, into the keel notch of the breasthook when attaching the keel to the frames.

Once this is accomplished, I would (d) laminate the remaining needed thickness onto the forward section of the keel.

My re-saw job on that big chunk of mahogany was less than perfect. I set my rip fence to cut a 3/4" wide strip. I knew I'd have to plane some surface irregularities from there, and I did. Two of the finished pieces were 5/8" thick when I deemed them "usable." In retrospect, I wish I'd planed them down a little further in an attempt at better fitting.

The remaining, "leftover" board is closer to 1/2" thick... or maybe even a little less. 

Due to some width irregularities, I shortened the 9' 10" length down to 9 feet. The Zip plans call for a 4" wide x 1" thick x 12' long keel.

So, where are we now? As you might have guessed from the title, we're at the point of having 3/4 of a keel. Let's take a look:

Sometimes, you just don't have enough clamps.

Somewhere in the middle of all that is the butt joint.

Butt joint and backing plate.
I used System Three Silvertip epoxy, thickened heavily with mahogany wood dust. I knew the fitting between the laminations would be less than perfect, so I wanted a good thick mixture to fill in any gaps. 

After the epoxy cured and I pulled the clamps off, I saw that some of those gaps had been bigger than I thought. Since the thickness of the laminated keel is now at almost 1-1/2" inches, I realize now that I could have safely planed away more surface irregularities and still made my goal of 1" combined thickness.

At the time, I stopped planing at "usable" because I feared the wood was getting too thin. 

Live and learn.

Ah well, epoxy-filled gaps or not, this is the keel, and I'm moving forward with it.