Project Hex: Building an Hexagonal Bird Table (Part 4)

Having got the roof fully tiled, focus shifted to the finish of the roof. As previously mentioned, I delved online to research  staining and weatherproof wood.

I could have simply slapped on some standard woodstain, but I wanted a more natural finish, something that lets the grain of the wood be the star.

A technique that caught my interest was one which naturally ages wood. Wood greys with age, just look at an old garden fence, or the oak timbers of a Tudor house. Some woods darken more than other, like English oak. This is due to it having higher levers of tannin than other woods. Over time sunlight and the environment darkens the wood.

The technique I found is pretty simple. You pop some wire wool into a jar of malt vinegar and leave it for a few days to a week. Brush this onto the wood and a chemical reaction occurs. The wood darkens with a beautiful grey-silverish tint, which deepens over a few days. If the wood you want to ‘age’ has low levels of tannin in it, then you need to add some… simply use stewed tea bags. Tea has high amounts of tannin, yes the wood gets a tea colouring to it, but the main aim is to get the invisible tannins into the wood. This is what I did to the roof of the bird table. Maybe red wine would have the same effect?? I didn’t try it.

The beauty of this technique is that it isn’t a stain, it is a chemical reaction. In essence, it is aging of the wood in fast forward. The effect is wonderful, the vinegar/steel mix collects and pools in grains, grooves, nick & dips. Here it darkens more than other areas, giving a very natural effect. The ‘aging’ vinegar concoction is pretty potent too. Apply it ‘neat’ and wood can go jet black in seconds. Whilst testing on some off-cuts, I found 1 to 20 dilution gave a slightly tinted effect. This is the technique I used, applying tint, allowing to dry, then repeating until I got the look I wanted.

The first treatment of the vinegar/steel wool mixture, you can see the wood darken slightly.

After a few treatments, the wood dries to a greyish-brown. You can see that the wood looks ‘aged’.

Another shot showing the ‘aging’ process.

The first treatment of tung oil goes on one aspect (the left hand side of this picture)

For weatherproofing, my research highlighted tung oil as the best option. The Chinese have been using the stuff for 1000’s of years to waterproof their boats. The reason it isn’t commonly used today is that it is a laborious task to achieve a good level of waterproofing. It isn’t difficult, it simply takes time. You have to apply it thinned down 50/50 with white spirit, so it soaks deep into the wood. Wait for it to dry, then repeat, gradually reducing the amount of thinner used. To do it properly, layer after layer after layer needs to be applied, eventually using it neat for several top coats.

The results are worth it, plus it has other benefits. It is not harmful to wildlife, as tung oil comes from a nut. Maintenance of the wood is easy, no sanding or scraping every year or so. Instead, every six to twelve months or so, simply brush some more tung oil onto the wood. It should be completely water tight, as the oil fills the gaps and fissures in the wood grain, then cures over time. I’m looking forward to seeing the rain bead off it in the garden, with the same satisfaction you get from a downpour on freshly waxed car bodywork ~ maybe that’s a bloke thing?

The ridge joins were filled with black exterior sealant prior to applying the tung oil.

The entire roof after a few applications of tung oil.

Outside, drying in the sun.

When the sunlight catches the wood, the natural translucent grain is brought out, giving a golden sheen.

The untreated (‘un-aged’), but oiled base and pillars have a lovely golden colour.

Reverse birds eye view… looking up into the eves.

The process has slowed down somewhat. As each application of tung oil needs to be left to thoroughly dry, it takes longer and longer between ‘coats’. This is due to the deep wood grains filling up with oil, so in soaks in less. It’s taking over two weeks for each application to dry now. Any ‘excess’ that is left on the wood surface will be ‘sanded’ down with 1000 grade wire wool – it’s more of a polishing than a sanding, plus it removes dust and contaminants that have stuck themselves to the oil. This result should be a satin gloss finish. I’ve periodically wiped away any excess on the roof tiles as I want a matt finish, plus ‘polishing’ the tiles would be a nightmare.

I am now at the stage of applying the third pure undiluted tung oil to all areas. I reckon that it will be waterproof in one more application, I will test with some water.

My focus is now on designing the stand and base. As the table is moderately heavy, the idea of having an integral hexagonal planter as the base seems the best way to go. When filled with soil and plants, there will be zero risk of the bird table blowing over in the wind.