I galvanising some chassis from Nissan Patrol and Toyota Landcruiser FJ55.
Galvanising have good part and bad part...
Good part.. good protection for inside the chassis
Bad side..very hard to paint or weld after.
I snad blasting an weld bad parts. Before galvanising, go to acid cleaning. After that, if company who galvanising the chassis dont clean very god the frame, many dirt, dust, mud and rust remain inside the frame and is not good because the galvanising process cover this dirty parts. So, clean the frame very good after acid clean.
For paint before galvanising, you need special primers and special paint (expensive)
Here is a galvanising frame form FJ55:
Here is a frame from Nissan Patrol Y60:
After paint:
