Steel may rust
My forged products all receive a linseed finish that helps prevent rust. For any products that are indoors and don’t get into contact with water, this should be sufficient to prevent rust long term. However, knives, axes and other items that get into contact with moisture or needs cleaning, it’s necessary to dry them off and apply a fresh coat of oil after use if you want to steer clear of rust. I always recommend raw linseed oil as it uniquely polymerizes and protects the steel long term.
Raw linseed oil vs. boiled linseed oil
The difference in function between raw and boiled linseed oil is that boiled linseed oil polymerizes quicker. Contrary to popular belief, boiled linseed oil isn’t actually boiled. The difference in the production process between the two is that boiled linseed oil have heavy metals added to it, and it is those additives that causes quicker polymerization. Unfortunately, these metals are also very toxic to humans and as such boiled linseed oil is not food safe whereas raw linseed oil is. Linseed oil is produced from flax and I always use raw linseed oil for my products as the slower polymerization isn’t an issue in my work as a blacksmith.
Please note that as linseed polymerizes the chemical process gives off heat, increasing the risk of rags soaked in linseed oil spontaneously combusting. This is especially an issue with boiled linseed oil where the process is quickened. Always store linseed rags in fireproof containers, burn them in a controlled environment or let them dry out away from anything flammable.