What is Wood Wash?
This mixture is a resilient and long lasting preservative for bare exterior wood. It is very a low viscosity liquid and so application is much easier than traditional varnishes. It soaks deeply into the wood and leaves wax and oils deep within the wood, rendering the wood much more resistant to water damage over years exposed to the elements.
Advantages compared to commercial varnishes and paints
-
Much faster to apply - splash it on copiously and it soaks in, no need to worry about drips or missing bits - it tends to run into where it’s needed. Because it’s so fast to apply you can do all your outdoor furniture in a few hours instead of it being a several-day painting/varnishing job.
-
Dries within a few hours in warm weather.
-
Better protection against water damage - traditional varnishes create a thin ‘plastic’ layer on top of the wood - almost like shrink-wrapping the bare wood - which very rapidly cracks and lets water in to the unprotected wood underneath, after which frost and further water will quickly destroy the wood and lift the rest of the varnish/paint. Wood Wash soaks into the wood and makes the wood itself waterproof. Once wood wash has been applied and allowed to dry the water visibly beads on the surface.
-
Nourishment of the wood - the waxes and oils replace natural oils within the wood and reduce the tendency of the wood to become brittle and weak over time.
-
Cost - Wood Wash is a DIY home-made product which is made from cheap, natural materials, and works out far cheaper than exterior varnishes and paints
Disadvantages compared to commercial varnishes and paints
-
Not available ‘off the shelf’ - Wood Wash has to be made up at home from basic ingredients.
-
Colour - Wood Wash is generally made up clear, unlike varnishes and paints which can be bought in a huge array of bright colours. Wood Wash can however be coloured by using spirit based wood stains or mixing in paints, but this is always relatively experimental.
-
VOCs (Volatile Organic Compounds) - The recipe for wood wash requires large amounts of VOC-containing solvent, usually white spirit or turpentine substitutes. These evaporate after application but VOCs apparently have a negative environmental effect.
-
Darkening - there is a tendency for dirt/dust to become absorbed into the grain of the wood, which means that over a period of 10-20 years the wood-washed timber will darken and can become grey/black. The underlying timber colour can be restored by sanding the wood back every few years, and wood wash re-applied.
-
Quantities - it tends to make sense to make large quantities of Wood Wash (eg 10-20 litres) up at the start of the season. It’s not quite as convenient as buying a few litres of varnish or paint as required.
Recipe
- White paraffin wax (available in decent quantities in agricultural wholesalers as horse wax) 1kg, melted
- Boiled Linseed Oil, 5 litres
- White Spirit, 12-15 litres
- Container - suggest a sturdy plastic vessel with a screw top closure
- Spirit based wood stain/dye (optional)
You will need a heating device eg electric plug-in hob to gently melt the wax. A funnel is useful for getting it all into the container.
-
Melt the paraffin wax over a gentle heat (I suggest to do this outdoors for fire safety)
-
When melted, start adding white spirit which will dissolve into it, keeping it all liquid even though the wax will be cooled by the white spirit.
-
Combine with the linseed oil and the rest of the white spirit, to make the total volume which will be around 20 litres
-
Add wood stain if required.
-
Place lid on container and shake vigorously to mix well.
Application
-
Apply using a big brush, ideally using a plastic sheet under the object you’re working on, as this will prevent staining of the ground. Refill the brush constantly and aim to soak the wood. If it all soaks in instantly - add more!
-
You can also ‘recycle’ wood wash which has dripped off, so there is less waste
-
Some small items can actually be immersed in wood wash, which gets the mixture right into the centre of the item and really adds protection.
-
Don’t let it drip on grass as enough of the mixture will discolour/damage the grass for a few weeks.
-
Don’t even try to apply it if it isn’t warm and dry outside. On cold days the wood wash congeals on the surface because the wood is too cold. The aim is for the wood wash to soak in and then the white spirit evaporates, leaving wax and oil deep within the wood.
-
Don’t apply to wet wood - the wood needs a good few days at least of a dry spell to really dry out the residual moisture inside the wood, this allows for best penetration of the wood wash.