The main difference between raw and boiled linseed oil is that raw oil takes much longer to dry than the boiled version. Raw linseed oil takes several days to dry, while boiled linseed oil usually dries within 24 hours.
Boiled linseed oil is not boiled in the way most people think of as boiling. Metallic solvents are added to the raw oil that cause it to dry faster. The process is similar to boiling, which is why it is referred to as boiled linseed. Traditionally, linseed oil is applied to wood and other surfaces as a drying aid. Raw linseed oil is best used on wood items when drying time is not an issue. These items include wooden gutters and sawhorses. Alternatively, boiled linseed oil works better for wood furniture, decks and any items that get heavy use. Therefore, choose the boiled variety when fast drying is required.
It is important to note that although linseed oil is derived from nature, it should not be applied to wooden chopping boards meant for food. Another thing to keep in mind is that linseed oil is not a wood preservative. It has no UV light protection, and applying it to wood provides no resistance to insect, fungus or mildew damage.