Top-coat or for high-heat exposed metal surfaces.
 
Graphite Grey is not a typical Linseed Oil Paint. It is used for both specialty exterior metal applications and high-heat exposed metal surfaces. Preserves metal and allows the surface to breath. Does not crack or peel like many modern coatings and prevents rust, as well as material degradation.
 
Graphite Grey Linseed Oil Paint contains the same graphite used in your reliable No. 2 pencil and is a traditional coating used extensively for demanding exterior metal surfaces, such as roofs, gutters, farming equipment, industrial structures, etc. before modern epoxy coatings and other petrochemical oil coatings became available.
 
For such applications, apply Graphite as a top-coat after the Iron Oxide Minium "primer".
It can also be used as a stove-blacking for metal exposed to high-heat such as cast iron stoves for example. No primer is used in this case. Apply the graphite directly onto metal and let dry fully before exposing to heat. Other pigments will not hold-up in high temperatures.
 
Note: 
Graphite Grey should not be applied on high-traffic areas or surfaces that will be touched or sat upon as it can easily leave marks or rub off.