This video shows the process of varnishing the whole bottom of the Petrel Play in nearly real time. I cut a few times as I moved the camera, and there is a brief section of accelerated time as the varnish drains through the filter.
I've gone over my varnishing process before, but in this video I am showing one complete coat on the hull from start to finish. I am using a 3 inch wide foam brush. I pour a small amount of varnish into a 1 quart yogurt container through a filter, then reseal the can immediately so it doesn't dry out. The boat has been sanded to 220 grit, wiped down with denatured alcohol and mineral spirits, and tack cloth. I mask along the sheer line so drips do not
I'm working on one 12 inch section (between the staple marks) at a time. After completing each section, I move on to the next section. After completing two sections on one side, I switch to the otherside. This maintains the "wet edge" which allows the new fresh varnish to flow into the slightly older varnish on the previous section.
If you spend too much time on one section, this wet edge will have dried to the point where the new stuff won't flow into the old stuff and you will end up with a thicker coat or brush marks between each section. This is the first coat on this kayak, so it is a chance for me to get back into the feel of the work. I am also using a brand new varnish for me, so I am trying to get the feel of this particular formulation.
I coat each section in a three step process: Apply, Level, Tip.
Apply the Varnish
I dip the brush into my varnish container about 1/2". I want a fair amount of varnish on the brush, but I don't want it dripping too much. To get rid of the excess I slap the brush vigorously on the inside of the container. Most people are familiar with the idea of dragging the brush across the edge of the container to get rid of drips. This just causes drips down the outside of your container. With a deep enough container you can slap the interiors sides so all the varnish that you removed from the brush stays within the container.
I use heavy strokes, forcing the brush against the boat. I am trying to get the varnish out of the brush, on to the boat. I'm using horizontal strokes, really bending the brush as I wipe it back and forth. I will typically start in the middle of the section, off loading the remaining excess varnish into the center of the section, then work back and forth from top to bottom of the section. Try to get some varnish on every bit of the section, but don't spend a lot of time at it.
For a kayak, one brush load is usually enough to go from Center/Keel Line to Sheer Line. A larger canoe may require you to re-dip your brush once more.
My goal is to get on more varnish than I need. The subsequent strokes will remove the excess.
Level the Coat
Now switching to vertical strokes, I brush up from the sheer towards the middle of the boat. Lighter pressure on the brush will barely bend the "bristles". I am trying to spread the spots where there is too much varnish onto the spots with too little.
Look for holidays as you go, dull spots where you missed while applying the varnish. A little extra pressure on the dry spots will help wet them out.
Be careful around feature lines such as chines or anywhere there is a crease or raised bump on the surface. These will want to scrape varnish off your brush, causing a drip or sag later. The Petrel has a chine so you will notice I brush up from the sheer to the chine and down from the keel to the chine, so I am not brushing across the chine.
Tip off the Bubbles
The final step is very lightly drag the tip of the brush over the surface in even stroke. You don't want to bend the brush much at all. Tipping off will actually pick up excess varnish. This is the process that provides an even, consistent thickness film of varnish. Drips and sags happen when one spot is a bit thicker than another. Overlap your strokes next to each other so the whole section is even.
If you have chines or feature lines, brush parallel to the crease so you don't drag excess varnish off your brush.
I brush from the dry side horizontally towards the wet side of the section. I will often go a little past into the prior section to help level the adjacent sections together. This also lets me pick up and drips that splashed as I was applying the varnish.
Now is the time to do a quick inspection, looking for holidays where you missed a spot, and drips where there is too much varnish. A quick stroke or two should be all it takes
Move to the Next Section
Don't stop to admire your work. Move to the next section. At the beginning of the process I'll do one section on one side, then switch, do two sections on the second side, then switch and do two on the first and keep switching doing two sections per side.
Peel the Tape
When you are done, peel the masking tape to allow any ridge formed at the edge of the tape a chance to relax a bit.
If you notice that I am splashing some varnish around a bit and thinking: "That's not good." You are correct, however, I am applying varnish to protect the epoxy, the more varnish I get on the boat, the more protection provided. I could apply the varnish with a quite dry brush, getting just enough on to make the surface a bit wet. I would reduce the risk of drips or sags substantially, but I would be working slower, get less protection on the boat, the gloss would not be as good, there would be more chance for brush marks, etc. I choose to slop on some varnish, paying attention to the splashing, and tipping off any drips that I should make. As a result I can get a nice heavy coat on quickly. As long as it is even when I'm done with the section, it will level off and dry to a smooth, shiny surface.
Since this is the first coat, I will be sanding it lightly before applying the next. This will serve to eliminate any sags that should get past me. By the time I've got 4 or more coats on, I'll be used to this new varnish and my feel for the process back and I'll be a bit more careful on the last coat. That is the only one anyone will ever see.