Conventional paints dry by the activation of synthetic drying agents. These drying agents force the drying to take place very quickly once exposed to oxygen within the right temperature range.
Not so for linseed paint. Linseed oil dries primarily by exposure to UV-light and oxygen. Usually, linseed paint dries fantastically well on a sunny day. Why not mimic sunlight to speed up the process when using linseed paint in a workshop or on shorter darker days?
With this in mind, I decided to do some research together with a UV light specialist and after trying various lamps, exposure times and distances to the object, we found that a painted surface exposed to UV-light dried to the touch in 5-10 minutes (from a distance of about 50cm between the lamp and object).
Sunlight comprises of 3 types of UV-light (different wave-lengths): A, B and C. Type C gets (mostly) filtered out by the ozone layer and B is the type that sunblock is used to protect against. Exposure to UV-A can be harmful and UV Light Technology Ltd work to the following times:
In Practice
Both areas on the left and right were painted in 1 coat of Histocolour Linseed Paint (colour Cast Iron). Both received a 5-minute exposure to UV-light and were dry to the touch after this time.
This exposure to concentrated UV light speeds up the aging process of the linseed paint, so make sure to not over-expose the paint, as you will have to keep adding new paint all the time.
No more waiting days to shut that freshly painted door or window or lengthy wait before putting on the next coat. Because these trials were so successful, I decided to start offering the UV-lamps online. So, should you have a large project or work with linseed paint on a regular basis, this lamp will prove an essential tool!
Watch this space for more details on my research!