How to Prime Wood for Oil Painting

Wood panels can be great for plein air painting. Normally I use pre-primed canvas, but for plein air painting they are too bulky, the sun shines through the back of them, and the canvas boards can be very thin so have a tendency to warp.

Wood panels are far better in my opinion but can be hard to find in art shops. This is how I prepare my own wood panels for oil painting and save some cash in the process. They are one of my fundamental plein air painting supplies.

1. Types of wood

You can use:

• Hardwood – A solid piece of wood. Be careful these can crack down the middle

• MDF - A fine powder of wood shavings mixed with resins and wax

• Plywood – Thin layers of wood glued together

You can find these as large panels at most DIY shops / hardware stores. Often the shop will be able to cut them into smaller sizes for you.

Most wood tends to warp a little - if you use smaller panels it’s not very obvious and not a big problem.

2. Wood Sealant

The difference between a wood sealant and a primer is that the sealant makes the wood panel waterproof, preventing any moisture or oil paint from coming in or out of the wood. This prevents the wood from rotting. Primer, on the other hand, allows the paint to grip to the surface and stick.

A sealant can be multiple things. You can use:

• Rabbit skin glue – Traditional, hard to find these days

• Shellac – A substance traditionally made from bugs in India, found in most DIY shops

• Glue

A word on glue (this is what I use for sealing). It took me a ridiculously long time to find it and understand what I was looking for.

Some art shops sell sealing glue as Golden GAC 100 medium. But you can simply use PVA glue. You can also use ‘wood sealant’, which seems to be the name for wood glue in DIY shops. This can be very helpful to know if you cannot find the words ‘wood sealant’ in the product description. Especially if you live in country where you don’t fully speak the language, as I do.

The substance looks like PVA glue, dries clear and peels off your fingers when dry - just like when you were a kid at school gluing sequins, glitter and random fluffy colourful things together.

Don’t go for varnish, that is a stain which makes the wood a different colour. I haven’t yet heard of anyone using it.

Both the back and front of the board should be coated with wood sealant to prevent warping and rotting. This means covering the sides too, particularly if you are using plywood.

Apply 2 to 3 coats, or as it says in the instructions. Lightly sand after each coat if you want a smoother finish.

3. Primer

This is Gesso - it’s white, not too expensive and easily found in most art shops.

On my search for sealant, I accidentality bought what I’m convinced is Gesso in a DIY shop. So if you can’t find it in your local art shop try the DIY place.

Apply about 3 layers for a good quality end product - again sanding in-between coats. Fine-grain sandpaper works best. Sand it until it’s super smooth or leave it rough, it’s personal preference.

4. Coloured Primer

You can paint onto the gesso directly, but if like me you don’t like painting on white, prime the wood as you would with any normal canvas. I always use some solvent, sometimes Liquin, and a small bit of oil paint to taint the surface.

This mixture tends to dry very quickly, especially if you wipe it on with a rag. So, if you are plein air painting and don’t want to decide on a base colour until you’ve seen what you’re painting, then you can do this last layer at your plein air painting spot.

Summary

The correct products can be found in art shops, but if you can’t get hold of them or they are too expensive, in my experience the equivalents can be found in most hardware stores. All you need are wood panels, sealant and gesso to get started.

I am very open to the fact that this is not the only way to prepare wood for oil painting… so if you have any suggestions, please leave a comment below and let me know how you do it!

Being unaware of the products you are using, I cannot guarantee that paintings on wood primed this way will last for the next 50 years to come.