Painting is the one thing that we have all done. Everyone has painted something. And as there are only a few choices of paints or varnishes, it seems impossibly simple to get it right. . . . Wrong.
The kinds of paints and varnishesAll paints have three main components, something that hardens and leaves a coat when dry, something wet that evaporates after being slapped on, and something that adds colour.
gloss (oil) paint
Why put finish on timber outdoors?For exterior woodwork, no finish at all is traditional. Oak goes black in time, cedar and larch are often said these days to weather to a "silver" colour. I say "ugly grey". But painting wood is not just about adding colour, it also protects the wood from moisture. And following moisture is decay. Some timber species are extremely resistent to fungus attack, such as oak. But the ubiquitous coniferous woods are utter softies.
To stop the rot, pine and spruce are today often pressure treated or dipped in decay-delaying chemicals. Keeping the timber relatively dry is a better preservative technique. The end grain is where much of the moisture enters and leaves timber, but this is quite often where the painter doesn't bother to paint (just look at the bottom of your front door if ever you take it off the hinges) and the end grain nearest the ground is the most vulnerable.
So, paint the pine. Make it colourful and lovely. And stop the rot. Some acrylic paints are now tough enough to be used outdoors, but you can't beat an old gloss paint. The problem is this: the paint needs to be renewed regularly. A five-year painting cycle is a recommended maintenance regime. But who wants to paint their doors and window frames and, god forbid, their gutters and facias twice a decade? And why does paint not last longer? As a product of the petro-chemical industry, we could be forgiven for thinking that paint could be manufactured to last twenty years or more. Well, don't think it's a conspiracy. Paint inside your house lasts and lasts and lasts. Outside it fails quickly. Most of us think the culprit is moisture. And that is partly right. When water gets behind the paint, it blisters and peels, and the water can get there for several reasons, including poor preparation and timber joints that move (because that is just what timber does). But paint also fails, slowly but surely, as its molecular structure is destroyed by ultraviolet light. Sunlight breaks down the strength of paint. That is why coat upon coat upon coat of paint will protect your woodwork beautifully. The oldest coats of paint are protected by the younger coats. But the final coat is always subject to the powerful rays of the sun. This is most noticeable when the timber has no more than a coat or two of polyurethene varnish. The varnish on a garden seat might not last more than a couple of years. Look carefully and you will notice that the bits in permanent shade, especially dark shade, will not have blistered (and note, many of these shaded bits are precisly those exposed to prolonged moisure).
What makes linseed paint so good?Traditional linseed paint is significantly longer lasting than ordinary gloss paint primarily because vegetable resins are far more impervious to ultraviolet radiation than are synthetic resins. The tree hugger might suggest that the mother sun that nourished flax (linseed) in life gave it the strength to withstand her withering rays even in death. There is probably a scientific answer too.
We believe, without any proof, that around traditional sash windows, traditional linseed paint simply has to bind well with traditional linseed mastic and linseed putty, and surely lasts longer here than any other paint.
The linseed paint that we mix up (we don't claim to make it) is not necessarily free of all manmade chemicals (although our suppliers say they are). The driers we add are natural turpentine from coniferous trees and the linseed oil is pure enough, but we can't speak for the heat treated oils that come from southeastern Asia (and it is the heated tung oil that really adds to the strength and, by god, to the cost!). Finally, the colour we add - and it wouldn't be paint without colour - is natural whenever possible. Natural pigments mean natural colours. The black is just carbon, the red is iron oxide, in other words, rust. The yellows and browns and reddish versions thereof all come from clay. This earthy range of colours is completely natural. Not so the blues and vivid red and most greens or even the white. But the pigments make up such a teeny tiny portion of the paint, even the tree huggers should let themselves off with choosing an unnatural baby blue.
Because it is so expensive, we have also devised a slightly cheaper and thinner linseed paint to use as a second coat. It takes much longer to dry. But before you faint at the cost, think about how much it will cost when, five to ten years from now, you don't need to pay for someone to paint your woodwork again.
Some traditional finishes on indoor timberFlat oil paint is the name some manufacturers give their traditional looking white-spirit based modern paints. But, of course, traditional oil paint is no more than oil, linseed or otherwise, with added pigment. At £25-30.00 for a 2.5 litre tin, our own proper traditional oil paint is not much more expensive than Dulux paint. See the results in an expensive Edinburgh Georgian townhouse, and you would say it was worth ten times the price.
Oil, particularly danish oil, is our favourite: easy to slap on and fairly environmental friendly (almost all commercially manufactured will have nasty solvent thinners/driers added). It produces a matt to slightly silky finish and is quite resistant to water. Linseed oil is great if you like shiny, but it takes eons to dry, so wipe on thinly.
"Milk paint" was the traditional paint for interior woodwork, so-called because it was literally made from milk. Also called casein (which is a milk protein) paint. Today it comes mixed with the required powdered lime and colouring ready to "just add water". Milk paint is meant to give a Shaker-like finish: natural, flat, and with a hint of irregularity in depth. Although something altogether different, some antiques dealers lump Victorian shellac paints into this category. More or less the same solid colour pigments as were used in milk paint were simply added to shellac (see below).
Wax was all the rage last decade. It isn't hard wearing and dirt will stick to it through the years, but the finish is nice to the touch. It usually sits on the surface of the wood without penetrating too deeply, so the wood does not darken too much. It is good, therefore, for retaining the lightness of the wood colour.
Shellac, or French polish, was the Victorian's favourite. It is increasingly hard to get, but easier to use than most people think. The traditional image of the French polisher is a man with his secret configured "rubbers" and figure-of-eight polishing technique (not to mention use of "rottenstone" or other polishing powders), applying twelve coats to produce a glass-like surface. But it can be almost as easy to slap on with a brush as oil. It dries almost instantly, faster than the fastest drying quick-drying varnish available in that tin that does what it says. This means you must be careful if adding a coloured pigment or there will be unsightly brushstrokes. But unlike almost any other finish, it is reversible. Subsequent coats can "melt" the previous ones. The whole lot can be taken off with methylated spirits (think of it as alcohol that you can't drink, but are allowed to sniff) - a far more pleasant prospect than paint stripper.
If you are lucky enough to have woodwork in your home that is still finished with its original shellac, tarting it up to make it look almost as good as new is not difficult. It may, however, be difficult to find a decorator who knows what to do. Most original shellac finishes tend to be dark, with mahogany a favourite (this was often achieved by adding a pigment known as Prussian Brown to the shellac, although the colour is rather more purple/maroon than brown). If you feel that you absolutely cannot live with this dark colour, removing the shellac with methylated spirit rather than paint stripper will be far cheaper in materials, far better for your skin and lungs, and allow you to refinish (using shellac) more easily and with better results.