Tips for Applying Varnish

Applying varnish to a boat is not much different than any other woodworking project, except the surface is usually larger and we can use techniques to cover large areas faster.

Use a low-nap foam roller, and apply the varnish to an area about 2' square, or about the distance from the keel to the gunwales on a canoe, two feet wide. The roller is great for its ability to spread the varnish evenly. The problem is that is will leave bubbles, and hence the next step.

Tip with a foam brush, moving from a dry area to the wet area. Make sure the tip of the foam brush has been wetted in varnish first. Do not play with it, you are just trying to to smooth the surface.

Then roll another section, overlapping your first area by a couple of inches. Repeat the tipping.

Move along your project until you have completely covered the surface.

Once the varnish has dried (refer to your product instructions), lightly sand with 220-grit sandpaper to dull the sheen and give the varnish some teeth to accept the next coat. You do not want to remove the first coa
t, just scuff it lightly. Build up at least 3 coats, but I'd recommend 5 or 6.

Always wipe down the surface between coats with denatured alcohol and a clean dry cloth. Do not use a tack cloth (they are impregnated by resins) or any cloth that has been through drier with fabric softener (like that old shirt you now use as a shop rag).

Just prior to the last coat, lightly sand with 600-grit wet sandpaper. Remember, it is intended to be used wet! Soak for 15 minutes before using, and keep dunking it in a bucket of water as you sand. This removes the dust and lubricates the surface. If used dry, it will scratch the surface unevenly.

When you are done, you will end up with a mirror-smooth finish.