Is spray varnish any good for wood?

Spray varnish is a popular finish for wood projects. It provides a smooth, durable coating that protects the wood from moisture, UV rays, and general wear and tear. But is it really the best option for finishing wood? There are pros and cons to consider when deciding whether to use spray varnish.

What is Spray Varnish?

Spray varnish is a clear, protective finish that comes in an aerosol can. The varnish is sprayed in light, even coats onto a wood surface. Most spray varnishes are based on either nitrocellulose lacquer, acrylic, or polyurethane.

Nitrocellulose lacquer spray varnishes dry quickly and provide a very hard, durable finish. They tend to yellow over time. Acrylic spray varnishes are also fast drying and resistant to yellowing but are not quite as durable as nitrocellulose. Polyurethane varnishes provide the most protection and longest lasting finish, but they take longer to dry and have strong odors.

Advantages of Using Spray Varnish

Here are some of the benefits of using spray varnish to finish wood projects:

Easy Application

One of the biggest advantages of spray varnish is how quick and easy it is to apply. You don’t need any special tools – just point the can and spray in smooth, overlapping layers. It’s much faster than wiping or brushing on a finish by hand. This makes it ideal for finishing large surfaces like tables or desks efficiently.

Smooth, Even Coat

It’s very difficult to achieve a perfectly smooth, uniform finish on wood using a brush. But spray varnish applies seamlessly in a fine mist to create an even coat. This gives your wood a glossy, professional-looking surface.

Dries Quickly

Most spray varnishes are formulated to dry rapidly, often within 30 minutes between coats. This means you can apply multiple layers in one day to build up a protective finish. Fast drying time keeps dust and bugs from sticking to the varnish as it cures.

Hard, Durable Finish

When properly applied, spray varnish dries to an extremely hard, durable surface that resists scratches, scuffs, and wearing over time. It provides much more protection than rub-on finishes like tung oil. The hardness varies by formula – polyurethanes form the toughest film.

Resistant to Heat and Chemicals

Quality spray varnishes protect wood from heat, spills, and chemicals. They create a protective barrier impervious to damage from hot cups or solvent spills. This makes them ideal for finishing tables, bars, and other surfaces that will see heavy use.

Enhances Wood Grain

Spray varnishes help bring out the natural beauty of wood. The transparent coat accentuates grain patterns and color variation. Using different gloss levels – from matte to high gloss – also affects the overall look.

Disadvantages of Spray Varnish

While spray varnish has some notable strengths, it does also come with a few disadvantages:

Overspray

Spray varnish can easily drift and coat surrounding surfaces if you aren’t careful to mask off the area. This can lead to sticky drips on countertops or floors. You also get overspray coating the wood surface unevenly. This requires extra sanding or thinning of the finish.

Inhalation Risks

The fine mist of varnish particles floating in the air can be accidentally inhaled. Extended exposure to these fumes can cause headaches, dizziness, and nausea. Always use spray varnishes in a well-ventilated area and wear a respirator mask.

Uneven Finish

It’s easy to end up with an uneven, blotchy finish if you don’t apply spray varnish properly. Moving the can too quickly or from too far away causes drips and thin areas. Perpendicular spray patterns and consistent motion is required.

Difficult for Small Projects

While spray varnish excels on large flat surfaces, it can be tricky to use on smaller items. The wide spray pattern leads to accumulation around intricate details. Brushing may work better for finishing carved decorations or legs.

Too Thick Coats

Spray varnish goes on rapidly, which often leads beginners to apply excessively thick coats. This can create runs, bubbles, and curing problems. Light passes from the proper distance is essential.

Requires Sanding Between Coats

To build up an adequate film thickness, multiple coats of spray varnish are usually required. But you must sand lightly between each layer to remove dust nibs and drips for proper adhesion. This extra sanding step takes more time and labor.

Not as Repairable

Since spray varnish quickly dries to a hard surface, it can be tricky to do spot repairs if the finish gets damaged. With brush-on varnish, it’s easier to blend new coats just in the affected area. Spray varnish may require refinishing the entire piece.

Hazardous Waste

The discarded cans of spray varnish contain hazardous materials and chemicals. Leftover varnish typically can’t be poured down the drain either. So you have to deal with properly disposing of the waste according to local regulations.

Tips for Using Spray Varnish

When working with spray varnish, follow these tips to get the best results:

– Always read and follow the product instructions for shake time, drying time, recommended coats, and thinning if needed.

– Mask off any areas you don’t want varnish coating with plastic sheeting or newspaper.

– Spray in a dust-free area without any wind, preferably in a spray booth.

– Shake the can vigorously for at least one minute before spraying.

– Hold the can 6-10 inches from the wood surface at a perpendicular angle.

– Apply light, even coats using a side-to-side sweeping motion. Overlap passes slightly.

– Let each coat dry completely before applying the next coat. Lightly sand between coats.

– Apply thin coats rather than trying to get full coverage in one thick application.

– Work in sections for large surfaces so varnish doesn’t dry before you finish.

– Dispose of used cans properly according to your local household hazardous waste program.

How to Choose the Best Spray Varnish

With so many brands and formulations of spray varnish available, it can be tricky picking the right product. Here are factors to consider when shopping:

Oil or Water-Based

Oil-based varnishes provide a smoother, more durable finish. But cleanup requires mineral spirits. Water-based options are lower odor and easier cleanup with just soap and water.

Gloss Level

Look for the sheen you want – high gloss, satin, or matte. Gloss shows off the wood grain while lower sheens have a more subtle finish.

Intended Use

Consider durability needs – tabletops need maximum protection while furniture accents need just moderate wear resistance. Get exterior grade for outdoor projects.

Application Surface

Make sure the varnish is formulated to adhere well to bare wood or as a topcoat over stained/finished wood. Some specific formulas work best for metal or plastic.

Drying Time

Faster drying spray varnishes allow you to finish projects quicker. But slower drying options flow out better for a smoother finish.

Brand Reputation

Stick with reputable national brands like Minwax, Varathane, Rust-Oleum, Krylon, or Deft that pros use. Avoid no-name products.

Reviews

Check reviews online to learn from other users’ experiences with the spray pattern, ease of application, and durability of the finish.

Price

Spray varnish costs $7-$20 per can on average. Bump up to premium versions for maximum clarity and protection on fine furniture projects.

Best Uses for Spray Varnish

Here are the types of woodworking projects where spray varnish really shines:

Tables and Desks

Spray varnish is perfect for quickly and evenly coating large tabletops. It leaves a beautifully smooth surface ideal for dining and work tables. Just mask off the base and legs first.

Cabinets and Built-Ins

Get a professional looking finish on kitchen cabinets, hutches, bookshelves, and other built-ins with ease using spray varnish. coat doors vertically to avoid drips.

Outdoor Furniture

Protect patio and porch furnishings from sun, rain, and snow with a resilient exterior spray varnish. It maintains the wood’s natural look.

Decor and Accents

Use spray varnish to seal and enhance wooden trays, bowls, frames, and other decorative objects. Just avoid overspray with careful masking.

High Traffic Areas

For surfaces that will really be put to use like workbenches, bathroom vanities, and bar tops, spray varnish stands up to constant wear and tear.

Turned Pieces

Get an impervious, glossy coat on rounded spindle pieces, chair legs, and other lathe turned projects with a few coats of spray varnish all around.

Quick Finishing

When you need to apply a clear topcoat to wood fast, bypass the brush and grab the spray varnish. Great for last minute gifts or projects.

Best Practices for Using Spray Varnish

Follow these top tips for getting flawless results when using spray varnish:

– Sand wood to at least 220 grit smoothness before spraying for maximum adhesion.

– Always test spray on cardboard first to check spray pattern and flow.

– Only spray when temperatures are between 65-90°F and humidity is below 85% for proper curing.

– Use thin coats and hold the can 6-10 inches from the surface to prevent drips.

– Spray side to side while moving vertically down the project to ensure even coverage.

– Allow at least 2 hours between coats and sand lightly to remove any debris.

– Finish spraying strokes off the project surface to prevent pooled varnish.

– Rotate and tilt rounded surfaces while spraying to coat all sides evenly.

– Add a coat of paste wax as a topcoat after the last varnish coat for extra protection.

– Clean spray tip immediately after use by turning can upside down and spraying until clear.

FAQs

Here are answers to some frequently asked questions about using spray varnish to finish wood projects:

How long does spray varnish take to dry?

Most spray varnishes are touch dry within 30-60 minutes. Allow at least 2 hours between coats. Final cure time is around 5-7 days. Oil-based varnishes take longer to fully harden than water-based.

How many coats of spray varnish should I apply?

3-5 light, even coats are recommended for proper protection. Re-coat only when previous coat is completely dry. Sanding between coats ensures proper adhesion.

What’s the difference between polyurethane and varnish?

Polyurethane is a type of varnish. Varnish is a general term for wood finishes. Polyurethane varnish provides a especially durable, water-resistant coating.

Should I thin spray varnish before using?

Only thin spray varnish if the product instructions specify. Typically, only required in hot, dry conditions to prevent orange peeling. Adds drying time.

Can I varnish over stained wood?

Yes, spray varnish works great as a protective topcoat over stained wood. Ensure stain is fully dry first. Lightly sand to help varnish adhere.

What sheen of spray varnish should I use?

It’s a personal choice. Satin varnish around 40% gloss is popular since it adds shine but minimizes fingerprints. Glossier for a slick look.

Is an HVLP sprayer better than a spray can for varnish?

HVLP spray systems allow greater control and can be less wasteful. But spray cans are far more convenient for smaller projects. Both work well.

Can I apply spray varnish over acrylic paint?

Yes, spray varnishes work as a topcoat over acrylic craft paints. Allow paint to cure fully first. Lightly sand and spray thin coats.

How do I repair damaged varnish finish?

Lightly sand the damaged area, wipe away dust, spray new varnish in thin coats, feathering out from repair area. Blend with careful sanding.

Conclusion

Spray varnish provides a fast, easy way to achieve smooth, professional-looking wood finishes. The spray application gives an even coat over large surfaces that would be very difficult to achieve by hand rubbing. Spray varnish dries hard and durable to protect wood from wear, spills, and UV damage.

While spraying does save time and produce great results, it also has some drawbacks to consider. Overspray, inhalation risks, uneven coats, and disposal issues can make it problematic for some situations. Proper spraying technique is essential for best results.

For many wood finishing projects, especially large flat surfaces like tables and cabinets, spray varnish is an excellent choice. Just take safety precautions, apply controlled coats, and spray varnish can help any wood project look its best for years to come.