I was trying to make linoleum through following recipes that are for making linseed varnish for wood. Please don’t try to redo this, linseed oil is highly flammable and I’ve read it releases toxic gas when heated.
I knew, that to make linoleum I would first need to make lynoxin. Lynoxin is basically oxidized linseed oil. Lynoxin is thicker and dries faster than regular linseed oil. To make lynoxin, I’ve boiled linseed oil (cold pressed) in a pan for around 5 hours while stirring air into it constantly. I was adding a little bit of drier from the art shop around the corner which is designated to let oil paints dry faster. The oil would turn dark brown and get a high viscosity. I measured the same amount of natural colophony resin and mixed it into the oil and heated it for another 2 hours together. After these 2 hours, the mix had thickened. I let it all cool down and mixed in shells of linseed pods as a filler. They replaced the sawdust that is traditionally used in linoleum. The linoleum would now feel like thick caramel. I needed to create an adhesion layer for the linoleum on the fabric, so I melted a very small part in the pan again and spread it out on the fabric while it was still hot. When it cooled down it became stiff and sticky and I was able to spread the rest of the linoleum on the surface of the fabric. To reduce the stickiness of the mix I used climbers chalk (magnesia).
It took several months for this sample to be completely dry and non-sticky. I’ve learned that it is normal that it takes so long, as all the linseed oil needs to oxidize in order to make a solid linoleum. Even in the industry linoleum sheets are hung up to dry for several weeks.