Not at all long-winded - very useful
I have noticed that the standard aerosol zinc chromate primer is pretty rubbish. It has poor adhesion and even the aerosol spray is uneven. I have tended to use 2 or 3 coats to get coverage.
But then I do only small items.
I will probably try to get hold of the Mapaero hardener... On the bottle (I have an empty one) it says
1,3,5-TRI(6-ISOCANATOHEXY-2-PROPYLE,XYLENE
(literally, including the missing closing bracket)
which picks up a few hits in google...