Old iron wood planes were
Japaned black. Folks try to
Restore that original look when
Trading and collecting them too.
Often they just resort to black
Enamels. Powdered asphaltum
Can be had if you want to try baking it
On. Asphaltum suspended in varnish is
Available from art suppliers too ,
supposedly it does a fair job. I believe
It’s more of a rust proof finish for metal
Than a water proofing. Or used for decorative
Enameling.
TC