Nancy’s Painting Blog

How to Prepare Wood Panels for Painting

Why Use Wood Panels for Painting?
There are many types of surfaces that painters can use for fine art painting. Canvas on stretchers have been used for a long time, and wood panels even longer. Wood is stronger and more durable then 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 causing 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. 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. Since commercial panels only come in standard sizes, and only up to around 40″ per side, if you want a custom size, or something larger than 40″ there are not many options. Some commercial companies offer custom panels, but may take up to six months (not kidding) to get it to you. Commercial panels use hardboard for the painting surface. Hardboard can get very heavy when used for large sizes. I created my own brand of panel, Nancy Reyner Custom Artist Panels, only available through, Artisans Art Supply. These are high quality panels, custom made in three weeks or less to your size preference, cradled with 1 7/8″ sides, and made with a special poplar wood material that is super lightweight.

Preparing Your Wood Panel
Oil painters must seal wood to stop any acidic oil in the paint, from penetrating into the wood support, which can cause the fibers to rot. While acrylic painters do not have this same issue, sealing is still an important step if you plan to use acrylic paint, 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.

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 by creating a barrier. A primer is a foundation layer that improves 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 seal the wood unless multiple applications are used.

A general rule is to apply at least two coats of sealer directly onto the raw wood to protect the wood. Then apply primer to enhance adhesion, return tooth to the surface, and whiten the surface for optimizing paint colors you plan to apply over it.

Instructions to Prepare Your Panel
(1) Clean off any dust or debris from all faces of the panel including the cradled sides, 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.

Tip: Let one surface dry fully before flipping over to seal the reverse side. Drying times can vary. If dry to the touch with no tack, it can be flipped over without sticking to the 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. There is no need to heavily sand, just an easy swipe with the sandpaper will suffice. Sanding blocks with a fine to medium fine grit are convenient for this purpose.

(5) Wipe the surfaces clean after sanding, then apply a second coat of sealer. Usually two coats of a sealer is sufficient, making the wood appear slightly satin or glossy in sheen. Optionally add more coats if you desire a more saturated seal.

(6) When those sealing layers are dry to the touch, it is recommended 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 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.

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 satisfactory when used with oil paint.

Once the gesso is dry to the touch it is ready for applications of acrylic paint. Wait 1 to 3 more days for applications of oil paint.

Here is a link for more information on Nancy Reyner Custom Artist Panels

35 thoughts on “How to Prepare Wood Panels for Painting

  1. In one of your videos…or books…you said Kilz woukd work as a sealer. At least I wrotr that down. Now i see…many panels layer…that it is an oil based product. Think all my paintings will self distruct? Thanks for any clarification.

    1. Hi Linda, I always use fine art materials and products if I can. I mentioned Kilz as a commercial alternative, and I do think it will work fine on rigid painting surfaces such as panels or wood (after all, it is made for walls not canvas). Kilz comes in both oil-based as well as water-based. If you are using oil paints it would be fine to use either type. If you are using acrylic paints, then it would be best to use the water-based. If you are concerned that acrylic paint will delaminate at the point where it is applied over the oil-based Kilz you may want to call the technical department for the company that makes Kilz and ask them. If you used a fairly thin layer of acrylic as the first layer over the oil-based Kilz and the Kilz was somewhat absorbent (not glossy) then there will probably be good adhesion between the two, with no delamination issues. What is important to understand is that there are many factors that determine adhesion strength between layers, as well as several processes you can do to increase the adhesion (ie. a light sanding of the underlayer before applying the over-layer.) Hope this helps.

      1. Hello! I want to use an Ampersand Panel for pouring an Acrylic painting. It will be a wedding gift. The panel was caught in a small flood in our basement and went unnoticed. Now it has some black mildew on the face and supports. What would you suggest is the best method, for removing and covering the spot so it will be useable? Also, the edges are raw wood. I want to use the edges so the painting doesn’t require a frame. I was planning to use Kilz after wiping with bleach then recovering with Gesso. Now, I’m not sure. Can you apply with a foam roller?

        1. HI Carol,
          I wouldn’t want to mess around with black mold. I would throw it out and purchase a new one. However, to remove the mold try researching how black mold is removed in regular households, usually on walls. Most likely there are chemicals to deal with this, but are probably toxic, which is why I would throw it out. Regarding the panel prep, whether you remove the mold or purchase a new panel, you would need to seal all exposed areas of the wood. You can use Kilz as you had suggested or GAC100 from Golden, or any Gloss Medium, applying any of these in two coats, then applying the Gesso. I don’t use a foam roller for any of these preparation coats, as I don’t want any bubbling. However, you can try using a roller and make sure it can apply the product smoothly without bubbling once dried.

    2. Thanks so much for all this helpful info! Lately I’ve been using flat birch panels which I coated with white gesso before starting to paint on them. Will there likely be a problem since I didn’t first coat them with a sealer, and also because I didn’t coat them with anything on the backs of the panels?

      1. HI Susan, if you did not seal the face of the panel, under the white gesso, you can still apply the sealer now OVER the white gesso, then apply the gesso again over the sealer layer. The sealer will absorb any of the water soluble impurities that move up into its layer, turning IT slightly yellow, but won’t let the impurities move up into further layers applied on top of it. You would want to apply the gesso, then, over the sealer to hide that layer and give you a nice white starting point again. You can always seal the back of the panel, at any time, if it is still raw even after the painting is finished, to keep it from future warping. If the painting is already in process or complete, and you are worried about problems because you have not applied a sealer to the face of the panel, under the gesso, then all will be fine IF you do not see yellowing at this point AND IF you do not plan to apply more layers that are thick. In other words, any yellowing due to impurities that moves upwards from substrate to upper layers, shows right away, within the first day at least, and will continue to move upwards only as thicker layers are applied, such as several coats of varnish, or heavy applications of gel.

  2. Hi, I will be painting on a cradled wood birch panel with acrylic paint for outdoor use in a humid climate (Bahamas). 1- do I follow your instructions for sealing a primer as above? (an artist friend recommended I seal with polyurethane, primer, paint and polyurethane over the paint to finish.)
    2- what do you recommend for weatherproofing?

    1. Since your painting will be outdoors, I recommend using a commercial product instead of a fine art product. Fine art products are usually not meant for outdoors. I think your friend is correct using polyurethane. Just make sure you use a good quality polyurethane – one that won’t yellow or crack over time. You can also take your painting to an auto body shop. They have very strong clear finishing coats they use on cars which are outdoors all the time.

    1. Yes. You can also use a general acrylic gloss medium. The GAC100 is a very thin polymer, so it will not show brushstrokes and will sink into the canvas or wood surface. While the acrylic medium is thickened a bit, so it can show brushstrokes. I recommend using either one, but with NO water added to dilute.

  3. Hi Nancy, can you tell me, if I want some of the natural wood to be left, unpainted in my background, can I apply the sealer only to the area that is to be painted? (working with acrylic on birch plywood if that is relevant) thank you in advance for your advice – and for this artcle!)

    1. If the wood is raw then it should be sealed in all places. Otherwise humidity could affect the unsealed wood risking warping. Why not use a clear sealer all over on all exposed areas of wood, and then paint wherever you want to paint?

  4. Hello Nancy

    I read this tutorial and thought this was awesome. I am painting on wooden panels right now and found this information valuable as I am not the most experienced with painting on wood. I wanted to ask you a question about preserving a wooden panel that was not properly sealed. One of the paintings I just finished was not sealed at all and I was wondering if there was anything I could do to help preserve the painting.

    1. I would need more information to give you an accurate answer. For instance, is it oil or acrylic that is painted on the wood. When you say not properly sealed what does that mean exactly? Was it partially sealed? Once wood has paint on it you can apply a varnish over the painted face to help. And you can always apply the stain sealer and primer I mentioned on all exposed wood surfaces, like the sides and back. You are welcome to write again with more details.

  5. Dear Nancy,
    Thank you for an informative article. I am wondering if you can answer a question? Years ago I took some faux painting classes in New York City. At that time, we primed with a product that also made the final finish feel cool to the touch like real stone.
    I thought it was gesso, but now cannot see to verify that fact. Can you tell me if it is gesso or if there is something else that I can use to create a cool feel? Thanks very much, Peggy

    1. Hi Peggy,
      Gosh I have never heard of such a product. I do know that all acrylic feels cool to the touch when it is still in its curing stage, which takes up to two weeks. After that I was unaware that acrylic can remain cool. I recommend calling the tech department at Golden Artist Colors, Inc. They are very helpful and will know. If you find out please let me know.

  6. I just would like to stay this is a great article! I used your steps to seal my wood panel and it turned out great! Thanks Nancy 🙂

  7. Thank you for this article! I was wondering for a cradled wood panel, do I need to also seal and prime the back? That would mean working around the wood that is cradling it as there are bars that go across the back, like a grid, not just around the edges. I think this is because it is a 36×48” panel and needs more support. I worry if I seal and prime only the accessible areas of the back of the panel and not the parts under the wood supports, it will warp. Any thoughts? Thanks again!

    1. Hi Bianca,

      That’s a very good question!You would only need to seal all the exposed wood areas. The wood that is underneath your crossbars as support is, as you said, difficult to get to, but this small of an area will not matter especially because it is probably touching the back of the main face of the wood. By the way, you only need one crossbar for every 42″ length. So you should only need one 36″ crossbar along the 48″ stretch of wood. The panels that my carpenter makes (which are sold commercially here do not need any crossbars because the special wood product used does not warp.

  8. Hi, I just did a painting that I really love on 1/4 birch plywood. However, I did not prepare the surfaces in any way, no sealer, no gesso. The plywood has a slight warp, but with the frame I made, it is not very noticeable. I’m concerned about future warping. Is there anything I can do now that I’ve already painted? Would sealing the back and sides help or cause more harm at this point? Thank you.

    1. If you go ahead and seal whatever wood is still exposed on the back and sides it will keep it from warping any more. Your front is painted, so that will keep the wood from absorbing moisture there, the frame is helping to shield the wood that it covers, so any wood that is still raw and exposed still has a chance of warping.

  9. Hello this has the mosst helpful piece I’ve seen about acrylic sealants, and thankyou for recommending certain brands as it makes it much easier to purchase.
    My question is slightly off topic but I have a large hollow decopatch reindeer I was planning on painting and I was going to seal it first, paint and then varnish like how you do with your wood panels, do you reckon this will behave in a similar manner?
    And if the piece is hollow would I need to do anything to the insides as well?
    Sorry for the odd question but I’ve been puzzling over it for a while.

    1. If the reindeer is made of wood that is raw, (unsealed) then you can follow the same instructions I gave for sealing the wood panels. If it is possible to seal the inside then go ahead. If not, just skip it. It’s always best to have all unsealed wood sealed, but sometimes it just isn’t possible to get to all the areas. Seal what you can and that will help keep it from warping.

  10. Hi and thank you for all this information. I am new to acrylic pouring and plan to use MDF panels due to it being much cheaper than canvas ( at least during the learning curve). Can i seal it with Liquitex pouring medium painted on with a brush?

    1. I would not. Each medium is specially formulated to work for different purposes. I would not brush apply a pouring medium, OR use it in place of a proper sealer. You need a thin formulation, and pouring mediums are a thicker pouring consistency. I recommend either Golden’s GAC100 brush applied, or any good quality gloss medium (just not one meant for pouring, or one thickened into a gel)

      1. Dear Nancy
        Thanks for your reply. I live in Sri Lanka and don’t have access to Golden products- even acrylic gloss medium is not easy to come by. What do you think about using an acrylic waterproofing kind of paint that us used for exteriors and interiors? I have researched the market here and such a product is available. It’s a white liquid ready to use.
        Thanks again

        1. That might work, although commercial products are not tested for long term archival use. In other words, noon-fine art products may sometimes flake, yellow or crack over time. It would be good to see if there is some way you can get any fine art quality acrylic medium. If you do use the waterproofing product that is available, it will be difficult to tell what will happen to it over time.

  11. Hi thanks for all this information. I’m new to acrylic pouring and plan to use MDF panels as a cheap alternative to canvas (at least during the learning curve). Can I use Liquitex pouring medium as a sealer?

  12. Dear Nancy,
    I’m so appreciative of your tutorial here. My question is how to finish the sides of these wood panels. I will be prepping the top as you have instructed and applying resin to the finished top surface of the piece (I will tape off the sides to prevent the resin from coating the sides). How, then, should I finish the sides? I like the natural look of the wood so would not cover it with paint. Do I stain and seal or use a particular medium to achieve a clean, protected, natural-looking finish? What finish would compliment the resin top? Any recommendations as to what products might work best here?
    Thanks so much!

    1. Hi Kim, I seal and prime all exposed wood areas (front, but also sides, and back) BEFORE I even start my painting. Once my painting is started I don’t want to risk damage to the face by turning it over to work on the back and sides. If you are using resin on the top I HIGHLY RECOMMEND you do whatever you need to for finishing the back and sides before applying the resin. Since you like the natural wood appearance, just seal it with the clear sealer I recommend (Golden’s GAC100), then don’t prime the sides with gesso. The sealer will slightly darken the wood (any liquid will do that with wood) and may give you the look you want. You can always experiment on a scrap panel to test whether the GAC100 will offer enough darkening of the wood. If not, then you can apply a tinted stain obtainable from any hardware store made for wood staining. You will still need to apply a clear gloss sealer over the staining to make sure the wood will not absorb moisture. Another reason you want to seal all over before applying thick layers of resin or paint, is that sealing the wood keeps it from warping BECAUSE the wood won’t absorb humidity unevenly. If you work on the face, while the wood is still raw on sides and back, you risk warping your panel.

  13. I’ve prepared 1/4″ birch panels with shillac and have been considering mounting raw canvas to them with archival PVA, but do I need to size the raw canvas prior to gluing and priming? I’ve stretched canvas before, and sized them with the gac100/400 combo, so I didn’t feel comfortable just gluing raw canvas to the board and throwing gesso (fake acrylic gesso) on it. After glued, do I need to seal the canvas prior to gesso or priming? I’d like to know that they are 100% as archival as I can get for DYI, even if my 5 year old is painting on them (with something other than oil paints). Thanks.

    1. Hi Josh,
      I do not recommend using shellac on panels. I would glue the raw canvas, unsized, to the panel. After the glue has dried, I recommend stain sealing the canvas with GAC100. If you skip this step you may get some staining coming through from the canvas into your paints creating a slight yellowing to colors. After the stain sealing with the GAC100, then apply one or more coats of a good quality gesso.

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