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The ABCs of Good Varnish

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There is nothing like good brightwork to add thousands of dollars to the value of your boat. But it takes work and time to get a great finish.  First, you need to get the wood prepared properly, and after the preparation you need to apply each coat according to the manufacturer’s instructions.  You also need to select the right brush and varnish for the job.

Head painter Javier Martinez, of the Jamestown Boatyard in Jamestown, Rhode Island, is manic about cleanliness when he sets about varnishing new wood.  "First you sand it with 80 grit and then 120 grit sandpaper," Javier says.  "Then you vacuum the job to get the dust off it. After you’ve got it clean, wipe it down with a solvent to get rid of any dust.  I like to use alcohol.  Then you are ready to varnish."

Martinez cuts the first layer of varnish by 60% to get good wood penetration.  "That coat is allowed to dry overnight and I sand it back using 220 grit or Scotchbrite pads."  The second coat is cut by 40% to 50%, which also gives it a good penetration into the wood.  After that, he applies straight varnish.  "I always sand between coats and wipe with solvent before applying the next coat," he explains.  "Each coat is left to dry overnight and gradually I build up a good layer of varnish." Javier Martinez expects to get at least 10 coats of varnish on any wood exposed to the weather on a boat.  Only that way will the wood be protected against water and the effects of UV degradation.

In the spring, any varnish work should be cut back using 120 grit.  Or if the varnish is in poor shape it should be taken back to bare wood and completely redone.   Using anything heavier than 120 grit, Javier says, leaves scratches in the bottom varnish layer and you don’t want that.  Aim to build up a thick layer of varnish at the beginning of the season, so that you won’t have to do it again during the summer.

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Other experts say that you should deal with damaged areas first.  Scrape away any bad varnish or graying areas of bare wood and "feather in" these spots with new varnish.  Only when you have repaired all the damaged areas should you start on the rest.  Try to avoid using stains on bad spots.  Even if you match it perfectly now, it will age differently than the rest of the brightwork and end up looking worse than when you started. 

Before you start on any varnish job you should mask off the area because nothing looks nicer than a crisp line where the varnish meets the boat.  You can’t ‘cut-in’ a good line freehand.  To try to do so is a waste of time.  The best tape to use is 3M’s Fineline.

When varnishing, pick the right time of day.  Try to wait for a calm, warm day.  Try to get a coat of varnish on early, so that it has plenty of time to dry before dark when dew might get on it.  Dew or moisture on the varnish may turn it hazy.  Don’t try to varnish when it is too cold or when it is too hot.  Too cold and the varnish will not set up properly.  Too hot and it will dry before you have time to finish properly.

Teak is more forgiving than mahogany when you are repairing damaged areas. With teak you work with different shades of brown, but with mahogany a bare spot will look red in a golden backdrop. After a couple of seasons everything will look the same provided you maintain it properly.

Teak, though, is extremely oily and varnish will not settle properly on it, so after sanding, wipe the teak down with acetone or other solvent. Start varnishing with a varnish solution diluted by about 50 to 60% as soon as the solvent has dried. You might also make it a practice to wipe your wood with a solvent and tack rag after cleaning it to get the surface totally clean. Maple is a very hard wood and you might want to dilute the first coat slightly more than normal to help it soak into the wood better.

If you want to build up a thick layer of varnish fast, use a clear polyurethane epoxy on the wood first. A good clear epoxy will provide a good finish but it does not contain any UV filters, so you will need to put two or three coats of varnish over the epoxy to build up the UV resistance.

As to varnishes, if you are going to keep your boat in the tropics, the word on the waterfront is that Epiphanes has the highest level of UV resistance and works best in the tropics. Schooner is the next best varnish and can be used as an exterior varnish but it doesn’t have quite the UV resistance of Epiphanes. Many pros, however, like it better because it flows more easily than Epiphanes. These are the two varnishes that stand out. Pretty much everyone else I asked said that other varnishes were similar with few hard preferences.

Roger Marshall is the North American Editor for the Yacht Report, former Technical Editor for Soundings, and a Director and the immediate past President of Boating Writers International.

The Right Brush

For good varnish work you need the right brush. Don’t buy a cheap one if you expect to get good results. Cheap brushes tend to leave bristles in the varnish work. You can use a throwaway sponge brush. In fact, many professionals swear by them. However, you will need to take care to get all the bubbles out as you varnish.

Badger hair brushes are reputed to be the very best brushes, but they are getting hard to obtain and are expensive. If you look at the tip of the bristles on a good brush you’ll see that they are split, rather like the split ends that your spouse is always complaining about. This is ideal on a natural hair brush because it holds the varnish better and provides a softer tip. On a synthetic brush the ends are solid, and if the bristles are stiff, they tend to leave lines in the varnish.

The idea with a good brush is to be able to carry a load of varnish to the job without dripping most of it on the way. Once the varnish is applied, the varnish should be “tipped out” to get it smooth and to eliminate bubbles. With a brush with a soft tip, this is relatively easy.

Keep your varnish brush for varnish only, and don’t use a brush that has already been used for paint.  It may leave paint streaks in the varnish.  Clean a varnish brush carefully after using it.  The better you clean it the longer it will last.  When cleaning, use the solvent recommended by the varnish manufacturer, not paint thinner which might leave residue in the brush.  Make sure you get well down into the bristles of the brush and then dry it carefully.  Store your brush either hanging bristles down or wrapped in a rag to keep the bristles all facing the same direction.

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