Why Use Wood Panels for Painting
There are many types of surfaces that painters can use for fine art painting. Canvas attached to wood stretcher bars have been used for a long time, and wood panels even longer. Wood is stronger and more durable than the fabric of canvas or linen, and is therefore more archival. Contemporary painting techniques such as pouring paint (i.e. Jackson Pollock) and gluing collage-style are much easier with a sturdy level surface such as wood. (By the way, Pollock did not use wood for his paintings).
Proper preparation of an artist support is essential for producing long-lasting artwork. Raw wood panels need to be sealed prior to priming and painting, to keep moisture from getting to the wood which causes warping and other damage. So once you purchase a wood panel you need to do two important steps before painting: seal to keep out moisture, and then prime to strengthen adhesion between the paint and wood panel.
What’s the difference between hardboard and Masonite
I get asked all the time about the difference between these two terms for wood panels. Click here for a great article that clears up any confusion between the two.
Where to Get Wood Panels
If you are lucky enough to have wood working machinery, you can make wood panels yourself, or hire a carpenter to make them for you. You can also go to any store that sells wood, purchase a sheet of hardboard (they come in sheets 4′ x 8′) and pay them to cut it up for you into custom sizes. The sheets runs about $20 and the charge for cutting will usually be an addional $15 (depends on how many cuts). For a reasonable price, then, you can get a stack of wood panels. Otherwise you can purchase commercially made wood panels from art stores and online artist supply sites. Ampersand makes great panels of good quality. They are the only commercial panel company that I know of that properly seals and primes their panels called Gessobord. Less expensive versions are available through Dick Blick and other online sites. Commercial panels can come with or without cradled sides (separate wood applied to the panel to add depth to the sides), and with or without coatings (such as gesso or other primers).
I have two issues with commercially made wood panels. I like to work large and in sizes that are not standard. Commercial panels only come in standard sizes, with maximum lengths around 40″ per side. If you want a non-standard size or something larger than 40″ there are not many options. Some commercial companies offer custom panels, but these may take up to six months (no kidding) to get it to you. Commercial panels mostly use hardboard for the painting surface which can get very heavy in large sizes.
Why is it Important to Prepare A Wood Panel
Oil painters must seal wood to stop any acidic oil in the paint from penetrating into the wood support, which can cause wood fibers to rot. While acrylic painters do not have this same issue, sealing is still an important step for using acrylic paint on wood, to eliminate Support Induced Discoloration (SID). SID is a phenomenon that occurs uniquely with acrylic paints. Supports naturally contain impurities that can cause an amber yellow discoloring to any light colored or clear acrylic layer that is applied to the wood unless the support is sealed properly. More about SID on GOLDEN’s website.
Sealing (sometimes called sizing) reduces chances for the wood to warp due to shifts in humidity, and therefore adds an important archival process to your artwork regardless of which painting medium you choose. Sealing also provides an easier surface to apply subsequent paint layers.
Sealers are often confused with primers. A sealer protects the underlying layer or material. It usually needs to be glossy (or non-absorbent) to properly protect the surface by creating a barrier. A primer is a foundation layer that strengthens paint adhesion onto the support. Generally a primer refers to a coating that prepares the surface for the acceptance of paint. Gesso is a primer and not a sealer. Gesso, when applied, has a satin or matte finish, is absorbent in nature, and therefore will not adequately seal the wood unless multiple applications are used – and this still may not seal.
A general rule is to apply at least two coats of sealer directly onto the raw wood to protect the wood. Then over these sealer layers when dry, apply primer to (1) enhance adhesion (2) return tooth to the surface, and (3) whiten the surface for optimizing paint colors applied over it.
Instructions to Prepare Wood Panels
(1) Clean off any dust or debris from all exposed areas of the panel including the cradled sides and panel back, first using a vacuum or air pressure if very dusty, then wiping clean with a microfiber cloth (or other lint free cloth) slightly dampened (with water).
(2) Lay the panel flat on a table, propping it up several inches on all four corners with jars, wood props, etc to allow for wiping away any drips, and ease of application.
(3) Apply a glossy acrylic medium over all exposed wood surfaces. GOLDEN’s GAC100 is made especially for this purpose. It’s special thin formulation of polymer acrylic, applied over the wood, soaks in quickly and minimizes brushstrokes and texture. GOLDEN has recently changed their advice saying that their Acrylic Gloss Medium works better as a seal then their medium called GAC100. I still prefer to use the GAC100 because it is thin and doesn’t create brushstrokes like the Gloss Medium. GOLDEN still says both work fine. You can also opt to use a commercial stain sealer like Kilz found in home improvement stores.
Tip: Let one surface dry fully before flipping over to seal the reverse side. Drying times can vary. When dry to the touch with no tack, it can be flipped over without sticking to the table or other props.
(4) When all exposed wood areas are sealed and fully dry, the wood will feel very coarse. That is because the wood grain gets raised with this first coat of sealer. Lightly sand all surfaces to smooth them using a 220 grit or fine sanding block. There is no need to heavily sand, just an easy swipe with the sandpaper will suffice.
(5) Wipe the surfaces clean with a slightly damp rag after sanding or vaccum, then apply a second coat of sealer. Usually two sealing coats are sufficient, making the wood appear slightly satin or glossy in sheen. Optionally apply more coats if you desire a more saturated seal.
(6) Once you finish applying all sealer coats and it is dry to the touch, I recommend to apply one or two coats of a primer, such as an acrylic gesso, especially to the front surface to regain surface tooth. Priming your panel, regardless of which paint medium you plan to eventually use, will add a second archival process to your artwork, by strengthening adhesion between your first painting layer and the primer. Opt to prime all surfaces, including the back and sides, for a clean white professional look. However, all you really need to do is prime the panel face that will be painted. To summarize you want to seal all exposed areas of wood, but priming can be just applied to the front face.
For acrylic painters, one coat of a better quality gesso, such as GOLDEN’s Gesso, will add adhesion strength between the sealed wood and your first layer of acrylic paint. Lesser quality primers are sufficient for use with oil paint, as oil seeps into the layers differently than acrylic. The lesser quality primer, though, does not have a high pigment content for extra adhesion strength that acrylic paints require.
Once the gesso is dry to the touch it is ready for applications of acrylic paint. To apply oil paint instead, wait 1-3 days or more.
Important: For this blog article I am offering information for fine art paintings that will be stored and/or displayed INDOORS. For information on outdoor projects, such as murals on wood, read this article.