Frequently Asked Questions
Can you use linseed oil paint on previously painted surfaces?Of course, is the immediate answer. But the life expectancy of the linseed oil paint is compromised by the paint below. In the first place, if the old paint flakes it will take the linseed oil paint with it. In the second place, no paint makes a particularly good bond to a smooth surface. That is why previously painted surfaces are often roughly sanded as part of preparation before repainting.
What is the best surface to paint?The advantage to painting a bare timber surface is that raw linseed oil will penetrate the timber itself. Resins, natural and artificial, vary in size as well as physical and chemical properties. The linseed oil molecules in our paint doesn't penetrate as deeply as raw linseed oil, because many have already bonded together as part of the pre-drying process they have been through. The resins that penetrate deeper into wood become part of its structure, if you like, and tend to bond more strongly. Acrylic molecules are quite the largest and hardly penetrate the wood at all, although they do bond to each other particularly well. In comparison to the resins that will harden and form the sealing paint skin, the pigments are quite large. Dyes will penetrate the timber, pigments will not. Nevertheless, pigments are small enough to enter the open grain of oak, for example.
Ideally, you should use sawn timber rather than planed timber. Planed timber presents a very smooth face with minimum surface area. Rough sawn timber has a much larger surface area and the protruding wood fibres offer the paint extra physical strength. The rough fibres help trap and harbour the pigments.