Wood is a beautiful material to work with and the right stain or sealant can really bring out and enhance its beauty. Not all sealants are created equal, though – using the wrong one can leave you with an effect other than what you intended. If you want to make sure that you use the best sealant to protect your work while keeping it beautiful, it’s important to know what qualities different sealants have. Here’s a side-by-side look at different sealant types to help you choose the right sealant for your project.
One of the best-known wood sealants, varnishes are typically oil or resin based and leave surfaces with a glossy finish. Varnish seals the wood and creates a hard topcoat that helps protect it. Most varnishes are applied with a brush, although aerosol varnish is also available. If you don’t want all of the gloss produced by typical varnishes, there are varnishes available that have additional components that dull the shine and produce a satin or semi-gloss look. Varnish can typically be removed using paint removers.
A natural sealant produced by an insect known as the lac bug, shellac can be used either alone or as a base coat for paint and other sealants to prevent color bleed. It provides good protection against water, but very little protection against solvents. It dries faster than most other sealants and can be removed as needed using alcohol or similar solvents.
Available in both water-based and oil-based varieties, polyurethane sealants are artificial varnishes that provide good protection against water and the elements. Water-based polyurethanes are typically referred to as acrylic polyurethane and produce a hard protective layer that can be buffed to produce a very high gloss. Oil-based polyurethanes are softer – as a result, they’re unable to attain the same level of gloss when buffed. Adequate ventilation is vital when using oil-based polyurethanes.
Another common sealant, stains are typically used to alter the color of the wood first and foremost. Many stains provide at least some protection from the elements, although they may require an additional topcoat application to get the most out of that protection. Depending on the amount of direct sunlight the stained wood receives, you may need to reapply stain every 6 to 12 months to maintain the look of the wood and the protection that the stain and topcoat provides.
Beeswax, carnauba wax and other waxes are sometimes used as wood sealants to provide short-term protection against the elements. The waxes can be difficult to apply to unfinished wood and are often sold as a paste or melted liquid to make application easier. Wax is difficult to remove, as solvents and sanding tend to liquefy it and drive it deeper into the wood. Frequent reapplication is required to maintain a protective layer as any wax on the surface is scraped off relatively easily through contact.
Unlike waxes, oils such as Tung oil and linseed oil are relatively easy to apply to wood. The oil may provide basic waterproofing, but serves more to beautify the wood than to protect it from the elements. A long cure time is required, sometimes upwards of 30 days; until the oil has cured, the wood may have a slight oily texture and oil can be transferred from the wood to other surfaces through contact.
Although it’s often used as an adhesive, epoxy resin can also be used as a wood sealant. After its curing period, epoxy creates a strong, but flexible protective layer that is next to impossible to remove. It’s best used on large, flat surfaces, as it’s very difficult to apply evenly over detail work; it works best when poured and spread. Most epoxy resins are transparent, although some will gradually yellow over time if exposed to significant amounts of UV light.
Which Sealant is Best?
The sealant you choose will depend largely on your specific needs. If you want something that produces a glossy finish, most finishes come in a gloss sheen however with oil-based finishes more drying time is needed before rubbing to a high gloss sheen.
If a satin finish is desired, a finish should be started with gloss because it is clearer and only the last coat should be a satin. The additives which make a finish a satin cloud the finish somewhat. If you want a hard protective surface, you should consider epoxy resins, conversion varnish or polyurethane and avoid softer finishes.
If the natural beauty of the wood is what you want to enhance, sealants that bring out the wood above all else then finishes such as oils and stains, should be at the top of your list. There are trade-offs for every option, but by comparing them based on their most prominent properties you should be able to find the sealant that’s best for your project.