Hi David
I made my heated cabinet out of an old bath with a radiator in it like this :-
http://i1138.photobucket.com/albums/...2032012545.jpg
I thought that with the door fitted the area above the radiator would work as a big heated rusting tank, but it didn't, as no rust formed on the test pieces.
So I put a rusting tank inside the heated cabinet above the radiator :-
http://i1138.photobucket.com/albums/...ps5345518b.jpg
And inside this are my test pieces rusting away :-
http://i1138.photobucket.com/albums/...psdaab9e60.jpg
As you can see they're already pretty well on their way to being blued
All the best Mick