Printer Friendly

A fine finish for outdoor wood: tips for using spar finishes.

A spar finish is almost exactly like the interior polyurethane finishes we're all familiar with. It forms a shiny coating that protects the wood while accentuating the color and grain. The application is the same as with interior polyurethane too. The big difference between spar and interior poly is that spar stands up to exterior conditions. It's more elastic, so it's less likely to crack as wood shrinks and swells from moisture changes. It also protects wood from UV sunlight damage. Originally developed for boats, spar finishes are now used mostly for outdoor furniture and entry doors.

You'll find spar finishes at home centers in gloss, semigloss and satin. A quart costs less than $20. Most formulas are oil based and labeled "spar urethane." Minwax Helmsman Spar Urethane is one common brand.


The end grain at the bottom of legs wicks up water like a thirsty sponge, providing a perfect home for the fungi that cause wood to rot. Sealing the end grain with spar (or any other finish) often fails because the end grain is so porous. Exterior wood glue fills the pores and seals out water much better. Brush on one coat, let it soak in and dry, then put on a second coat for good measure. If you slop any glue onto the visible sides of the legs, wipe it off and resand the spot before finishing.


To maximize the amount of finish your brush can carry, dip it in the can about a third of the way. Lift out the brush a few inches, then jab it toward the can to release excess finish. Dab the end of the brush on a white cotton rag to remove any finish that may have puddled there. Hang on to the rag as you work in case you need to wipe off excess finish inside a corner or around an edge.


Even when wood legs are sealed (see tip above left), they shouldn't stand directly on wet or damp surfaces. Plastic glides provide the perfect moisture buffer. A pack of four costs about $2 at home centers.


When you start brushing the first coat of a spar finish, begin at the bottom of your project and work your way up. If you get any runs or drips as you go, they'll fall on a finished surface and you can deal with them when you're ready. If runs or drips fall on an unfinished surface, wipe them up right away so their edges don't leave a shadow line.

TIP: Run screws into the ends of the legs to serve as standoffs. This way, you can start brushing at the very bottom of each leg.


After you're done brushing a section, aim a light at it to check for drips. Hold the light at a low angle so the surface looks glossy. Even tiny runs, drips and skips will be easy to see.


If you spot a drip, stab at it with a dry brush, a technique called "stippling." (To temporarily dry your brush, just wipe the tips of the bristles on a paper bag.) Brushing out a drip that has started to dry makes a gooey mess. Stippling is less likely to leave permanent blemishes. And if it does, the imperfections will be smaller and easier to sand flat after the finish dries.


Spar in a spray can is convenient and provides a smooth, flawless finish. But it costs about $9 per can, and a midsize project might require five or 10 cans. So here's an economical approach: Brush on two or three coats, then after final sanding, spray on a final, perfect coat.

by Tom Caspar
COPYRIGHT 2015 Home Service Publications, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2015 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:GO TO THE PRO!
Author:Caspar, Tom
Publication:The Family Handyman
Geographic Code:1USA
Date:Oct 1, 2015
Previous Article:Simple kitchen shelf: easy for anyone to build--and fun to customize!
Next Article:Stone accent wall: cover a wall with stone veneer and transform a room!

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters |