Has anyone had any luck painting wheels that have been soaked in linseed oil? What kind of paint would work?
Yes. On Boiled Linseed oil. I have used Urethane over it. I also have used Enamel paint (Rust-o-leum and Tractor paint) over the oil and over the Urethane. I have wheels I painted in 1982 that still look new. I brush it on. I claim that the slow drying enamel remains flexible and tends to chip less than harder paints. It is good to give it time in between coats and to sand or scuff it in between.
Others have their favorite processes and I hope they will share them too.
Brendan - once the linseed is reasonably dried (I cut mine with mineral spirits to aid in that process), painting over it is no issue. I have painted over metal that was coated in linseed oil with no problems.
I usually mix an oil base (rustoleum) with the linseed oil and it comes out good a mixture of 1/3 gloss black with 2/3 linseed oil gives a good weathered look.