Linseed oil coatings on forging

Hi all!, just joined the group.
I’ve recently scorched some boiled linseed oil onto some hinges for an oak gate. It seemed hard as nails and I couldn’t even scratch surface with my nails. When hinges where fitted and it rained.the strap hinges bled black stains at the back onto the wood.
Could the coating have reacted with danish oil or oak? I’ve no clue?!
Any experience of this and a solution would be well received. Daz

Iron reacts with tannin in the oak to produce a black stain on the oak, there are some nasty chemical concoctions that you can use to bleach the oak back to white but unless you can completely waterproof the wood as well as plate or seal the iron wherever it contacts the wood, the stains will probably return.
btw: Tung nut oil works a lot better then linseed oil in many applications. In its pure form tung oil is a non-toxic hardening oil that works great on wood, a thin coating applied to tools can protect them from rusting. Tung oil might provide a superior seal between the iron and oak and a finish coat over the assembled parts will help seal out water intrusion for a while, but eventually the elements will conspire against you.