PxPixel
Know how: Varnishing your Sailboat - Sail Magazine

Know how: Varnishing your Sailboat

Any brightwork on your boat, inside or out, needs regular maintenance to stay in top condition. Varnishes are expected to fulfill two important functions—they enhance the natural beauty of the wood and protect it from the elements.
Author:
Publish date:
BW-varnish-top
Some finishes contain pigments, which color the wood as well as provide a protective coating

Some finishes contain pigments, which color the wood as well as provide a protective coating

There are few boatowners who have never walked the docks and marveled at a beautifully varnished rail or hatch cover. Even boats with no exterior varnish often have some brightwork down below; fiddles, door frames, bookshelves, and mast supports are often finished bright to break up a stark white interior. Any brightwork on your boat, inside or out, needs regular maintenance to stay in top condition.

Varnishes are expected to fulfill two important functions—they enhance the natural beauty of the wood and protect it from the elements. One of the greatest threats to varnish is sunlight. Though all exterior varnishes should contain UV inhibitors, all finishes will eventually break down when continuously exposed to bright sun. As the sun penetrates the finish, it lifts the varnish from the wood. You’ve probably seen a teak toerail whose wood is turning black under a smooth exterior. Because the varnish is no longer adhering to the wood, it must be removed and replaced to restore the finish and provide the necessary protection.

The greatest investment in varnishing is the time put into applying it, so a cheap $20 varnish may not be such a bargain. It’s worthwhile spending extra for a top-quality varnish and having the finish last as long as possible. Be sure to use a varnish that is designed for marine use.

FINISH TYPES

ONE-PART VARNISH. There are three basic finishes for wood: one-part varnish, two-part varnish, and oil finishes. Within these categories are a number of variations—clear, satin, gloss, and matte finishes; polyurethane and tung oil bases; products that do and don’t require sanding between coats.

letonkinois2

One-part varnishes can be used straight from the can. Their three main components are an oil, a solvent, and a resin. These varnishes are somewhat flexible and can expand and contract as weather affects the wood they protect. This makes them an ideal choice for covering large areas on boats.

TWO-PART VARNISH. These finishes come in two parts—a clear coating and a hardener or catalyst. When they’re mixed together in the correct ratio, a chemical reaction occurs that results in a very hard, tough finish. Once mixed, the application process for a two-part varnish is the same as for a one-part varnish.

Penofin

OIL FINISHES. An oil finish has a higher oil content than a varnish and less solvent and resin. One of the great virtues of an oil finish is speed of application, even if numerous coats are used. But oil finishes must be applied more frequently than varnish. I’ve had good results using an oil finish belowdecks, where it holds up well.

COMPATABILITY

Suppose you’ve just bought a used boat. How can you tell what surface coating has been used and whether a new coating will be compatible?

One way to check whether the surface treatment will be compatible is to tape off a small, inconspicuous area and try applying a thin coat of the desired finish. Leave it for 24 hours and if it dries with no signs of crazing or alligatoring then the two should be okay together. It is worth noting that two-part varnishes are hard and can be over coated with a one-part finish but the reverse is not true. A two-part product used over a one-part finish will crack and flake due to the movement of the flexible undercoats.

Bristol%20finish

The one sure way to solve compatibility problems is to remove all the old finish and start fresh. This sounds like a lot of work, and it can be—especially if you have acres of varnished wood aboard. But it’s the best way to revive an existing surface in poor shape, and it could save you time (and money) in the long run.

Over coating an oil finish with varnish is often less of a problem, as oils are often present in the composition of the varnish. Even so, you should try the two together on a small test area.

PREPARATION

One thing I’ve learned over and over is that the best finish starts with meticulous preparation. Stating off with bare wood is in many ways easiest, because you don’t have to worry about compatibility with any previous coatings. Especially if the old coating is in a state of disrepair, it’s best to remove it completely. I like to use a hot-air gun and a sharp scraper. Use sandpaper only as a last resort; it’s slow and expensive, it gums up, and it creates a lot of dust.

interlux-perfection

If the previously varnished surface is in good condition, you can give it a thorough wash-down with plenty of clean water and then sand the surface with either 320- or 400-grit wet-and-dry paper. Use it wet to smooth and prep it for additional coats of varnish.

APPLICATION

Using the correct application technique is the key to a perfect finish, which is why it’s imperative to follow the instructions on the varnish can to the letter. Don’t varnish on a damp day or when the air is full of dust. It pays to use the best brushes you can lay your hands on; natural bristles are best. Keep the brushes you use for varnishing separate from paint brushes and use them only for varnishing.

BW%20varnish%20brushes

CONCLUSIONS

After many years of varnishing, my personal preference is to have a rubbed oil finish belowdecks and a gloss-finish one-part varnish on all above decks brightwork. I know many varnishers who swear by their own favorite brand, and they get nice results.

pettit

I strongly recommend that you choose one finish and then stick with it. Get to know one product well, learn how to apply it properly, and you’ll be rewarded with a finish your boating neighbors will admire.

There’s a lot of advice on varnishing available. My favorite is Brightwork: The Art of Finishing Wood, by Rebecca Whitman (International Marine, 1990). Lavishly illustrated with stunning photography, it contains a wealth of knowledge on all things that deal with varnishing.

TOP TIP

Sanding off an existing finish is often the least effective method; it makes clouds of dust and is hard work. Use a hot-air gun and a sharp scraper; the finish will come of much faster and with a lot less damage to the underlying surface.

PROS AND CONS

interlux-jetspeed

One-part varnish

PROS: Less expensive than two-part varnish; flexible; easy to apply

CONS: Not as durable as two-part varnish; must be applied in warm conditions

Two-part varnish

PROS: Very hard surface; ideal over an epoxy finish

CONS: Expensive; can be tricky to apply properly

epifanes%20small

Oil finishes

PROS: Easy to apply; economical

CONS: Can look artificial especially if a stain is added; needs to be redone more often than varnish

RESOURCES: American Rope and Tar; C-Tech Marine; Daly’s Wood Finished; Epifanes; Flood Company; Interlux; Performance Coatings

Related

01-061018ROAC-8149

Coming of Age at the Atlantic Cup

Midway through the final race of the inshore portion of the 2018 Atlantic Cup, the three boats in the lead—Mike Dreese’s Toothface 2, Mike Hennessy’s Dragon and Oakcliff Racing, representing the Long Island Sound-based sailing school of the same name—suddenly broke free from the ...read more

01_silken_2018-03-08-0052

North U’s Regatta Experience Program

“Want to check the keel?” North U Coach Geoff Becker calls to me from back by the transom. We’ve just suffered our worst finish in the regatta and are absolutely flying on our way back to shore, spinnaker up and heeling at an angle that feels like maybe we’re tempting fate. ...read more

Navy-Sand-Dune_1080

Tucket Footwear’s Giller Shoes

Just for KicksMove over Crocs, there’s a new plastic shoe in town. Unlike the aforementioned fashion crimes, Tucket Footwear’s Giller shoes are made for boating. Water will get in, yes, but it will also run straight out again via rows of “scuppers” in the uppers and a dozen drain ...read more

01-m3113_git170829-294

France’s Maxi-tri Ultime class

It’s hard to believe how far foiling has come since the Moth class figured out how to reliably take to the air in the early 2000s.Was it really only in 2013 that the America’s Cup was dragged kicking and screaming into the foiling world by Emirates Team New Zealand back in San ...read more

GGTobagoCays

Cruising: Guadeloupe to Grenada

Our Dream Yacht Charter delivery started as a “wouldn’t it be fun if” idea. Those are usually misguided, if not downright stupid. But a Bali 4.3 named Jumelles (French for “twins,” appropriately) needed to leave Guadeloupe to do heavier charter work in Grenada, and as soon as I ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell.Got a tip? Send it to sailmail@sailmagazine.comWhen I bought my boat it had 18 through-hull fittings. To reduce the number of holes in the hull (I ultimately cut them by half), I first re-plumbed the drain hoses from my sinks, scuppers, bilge pumps and ...read more

rokk

Scanstrut: ROKK Charge+

It RokksWith the increasing use of smartphones and tablets for in-cockpit navigation comes the issue of keeping these devices charged, since running nav software will drain those batteries in no time. Scanstrut has come to the rescue with the ROKK Charge+, the first-ever ...read more

GreenCove2-2048

Liveaboard Voting Rights Threatened in Florida

Bucking decades of precedent, a Florida elections officer is refusing to allow customers of a popular mail forwarding service to register to vote in his county. Since 1988, St. Brendan’s Isle of Green Cove Springs in Clay County has provided transient Americans with mail ...read more