Paint it thinly and brush it outPainting is the one thing that we have all done. So we all have expectations of the paint we buy. Normally paints are thicker when wet and thinner when dry. That's because normal paints are dissolved in a solvent, whether white spirits or water. When the solvent evaporates, the paint dries. Drying oils, like linseed oil, harden as carbon atoms in the oil molecules bind to other carbon atoms. Part of this drying/hardening process is the capture of oxygen atoms. So the oil actually becomes heavier and thicker as it dries not thinner. So there is the first strange fact about painting with linseed oil paint that you probably didn't need.
The drying metals in our oil act as a catalyst for this absorption of oxygen. Alas, they work so well that the paint surface, exposed to the air, hardens much quicker than the oil below it. As the oil underneath manages to capture oxygen the surface film get larger and, with no where to go, starts to buckle and fold upwards. The result is some fantastically convoluted, i.e. wrinkly, surfaces. So the paint has to be applied very thinly. This is not as easy as it may sound, because the paint is also thin and runny. So it tends to pool. And this is precisely where the paint will wrinkle badly. We recommend that you go back over painted surfaces with a wiped clean brush thinning any areas where paint has collected some fifteen minutes after initially painting it. Doing it again after, say, an hour is not a bad idea.
Our paint will appear thinner and runnier than you will probably expect. At least this will help you with the two rules of applying it: paint thinly and after 10-15 minutes brush out the painted surfaces, especially around edges and ledges.
The painting regimeOn new, raw wood, we recommend a first coat of boiled linseed oil thinned with turpentine if you are mixing it yourself. We supply an alternative as a pre-treatment oil. The intention is to saturate the wood as much as possible with the oil, reducing its ability to absorb moisture and thus reducing fungal attack. Pre-treatment oil will penetrate more deeply into the wood than our paint, the extra solvent penetrates deeper, pulling some of the oil in with it. Any excess oil applied on this first coat should be wiped off if you use raw linseed oil, for it takes a long time to dry. Our pre-treatment oil usually doesn't need to be wiped off.
Then comes a coat of paint, applied thinly. Dark colours will look good even after only one coat. Light colours will probably look a bit feeble.
Allbäck/Holkham Paint will tell you to wait 24 hours before recoating. Non-commercial websites say 4 days to a week for linseed oil paints. Given that Scandinavian academic reports on the viability of the industry underline the long drying time as the main reason why linseed oil paints are not suited to the modern building industry, the 24-hour claim by our rivals seems overly optimistic. And we have been told regularly by those using the Swedish linseed oil paint that 4 days is probably necessary. You will find that raw linseed oil can take months to harden properly. But let's face it, if repainting could begin exactly one day later, linseed oil paints would have no significant disadvantages over any other paint in application. Who tries to apply two coats in a day? So, be prepared to leave a bit of time between coats.
On a fine day, our own linseed oil paint really does dry in 24 hours if not 12. Indeed, it can be touch dry in 8. But painting a second coat straight away is not necessarily a good idea, even if it is possible. A second coat is much more liable to the wrinkling effect than the first coat. We suggest that you wait several days between coats if it is feasible.
Sanding between coats?Normally, one would expect to give a surface a light rub down between coats of primer or paint. Natural oil paints, however, are quite rubbery. They don't take well to vigorous sanding. A light rub with a sanding sponge or a harder rub with an open nylon mesh scourer is about all the newly painted surface can support. After painting the second coat you can sometimes call it quits. My own windows were painted by a professional and only given two coats of black and look great. You may wish to add a final, third coat, or you may need to depending on the colour of the paint and the underlying surface. For instance, applying white linseed oil paint over a previously painted white surface may only require one coat. Applying it over a dark and mottled timber surface will probably require three.
That's a lot of painting. You could always thin the final coat with boiled linseed oil bought at any diy centre and most hardware shops, padding out your expensive paint and allowing you to use up every drop.
How others do itThe following link will take you to a web site where someone has used linseed oil paints, our own and our Swedish rivals, complete with advice and photographs.
IDOSTUFF . CO. UK demonstrating stages of applying our duck egg blue to windows