Woodworking - Brief to do

Protecting Exterior Wood for a Lifetime

For this project I used two ancient techniques for protecting exterior wooden gates, these old methods out perform most modern film finishes for wood.

The first preservation technique I’ll be using is from Japan and called 焼杉 “yaki sugi” or 焼杉板 “shou sugi ban”.

There are many ancient homes in Japan that have this famous black carbonised wood on the exterior.

The carbon surface stops insect penetration and protects against the harmful effects of sunlight.

The best types of wood to use are cypress or cedar, unfortunately they are both expensive where I live and so I used a Chilean pine for the gates.

I made a quick test of burning the wood with a weed burner at four different grades of intensity, I then washed the wood with some water and a stiff nylon brush in the direction of the grain.

I personally prefer the look somewhere between test two and three but the fourth test would probably give better long-term protection.

I went on to burn all the pieces of cut wood for the first gate.

On to the second process of protection.

I melted 125 millilitres of bees wax using the “bain-marie” method which is heating indirectly via boiling water.

If you use a blow torch to heat the water bath make sure you are outside away from any buildings, a safer method would be to use an old individual electric heater.

After 10 minutes the bees wax has melted, I add 500 millilitres of boiled linseed oil which is flammable hence the blow torch needs to be turned off.

Give the mixture a good stir we end up with a 4/1 mixture of linseed oil to bees wax. Leave the mixture to cool down overnight.

The following day I apply the congealed mixture to all sides of the wood using a rag and protective gloves.

The consistency of the mixture is like grease.

The sheen of the burnt wood surface is amazing after applying this goop.

Make sure you do this process outside as the mixture doesn’t smell too good, the odour does go away as the mixture dries out.

I can show you what the four gates will look like once installed.

I intend to check the condition of the gates every six months

I’m guessing that I will need to reapply the wax / linseed oil mixture once per year to keep the wood in optimum condition.

In theory these gates should last for a generation or more which is good enough for me.

Some of the things I used.

Gas Torch Burner 2m Hose – https://amzn.to/3PMl3H1
Vertical LP Gas Tank 20 lb – https://amzn.to/43hmEYq
Boiled Linseed Oil – https://amzn.to/3ri8YPs
Bees Wax – https://amzn.to/3O3dj1V
Cordless Circular Saw – https://amzn.to/3Khb8Go
Multi-Purpose Table Saw – https://amzn.to/3m0wMor
Table Saw Push block – https://amzn.to/3EcJSoT
Cordless Drill / Screwdriver – https://amzn.to/3xwRGxZ

So your plywood is bent, cupped or bowed? You will need to apply some hot water with a sponge or rag to the concave side of the board (image below).

I fixed a small piece of 1/2″ or 12 mm plywood board with a bad bow.

If the warp is only present in one section of the board then you only need to dampen on the concave side of that specific area.

If you need a sponge.

Large Multi Use Sponge – https://amzn.to/3ZnAjeS

Put the board in direct sunlight with the wet side facing downwards. The resting surface needs to be flat I decided to use our driveway.

Place some form of weights on the upper side I used pavers. Leave the board to dry and the bowl should disappear within an hour depending on how hot it is. The temperature was about 88 Fahrenheit or 31 Celsius.

Check the board every 20 minutes to see how things are going. If you overcook the board it will warp in the opposite direction.

After an hour had passed the original bow was gone but I overcooked the board which now has a slight warped facing upward and is 90 degrees offset from the original bow.

To fix this I’ll wet the concave side of the new warp and place it face down and leave it to cook for just 30 minutes.

This the three sides of the plywood board are perfect and the other edge has a tiny warp on one side which is okay for my needs.

I know this fix is limited to sunny conditions so some of you may have to store your warped plywood until the Summer arrives.

I would recommend securing the board with screws as soon as possible after fixing the warp as some boards just want to return to being bent for life.