Well, with regard to protecting the chassis from rust, it's worth bearing in mind that the chassis mostly rusts from the inside outwards. So no matter what you put on the outside it'll only protect the chassis a small amount.
Sadly once the rust is into the chassis, you're fighting a losing battle.
There Is that. I was thinking of spraying waxoyl through all the awkward bits where water could have gone in. If I can keep the chasis where it is I will be happy.
I have this vision of a pretty underside. Is this just rubbish?
Also please bear in mind, I am having lots of fun trying to fix stuff on this car... Lots of fun.
My thoughts are so far....
Paint a rust remover on the bits I can easily see such as the radial arms etc and wash that off. Remove surface rust, degrease and blast it with a power washer. Leave and paint first with a zinc containing primer and then silver tough paint such as hammerite. If this survives this winter with no blemishes / additional rust spots etc, then this may be a good way to protect metal,you can get to easily.
My thoughts on the ladder chasis is to do paint the rust remover on the bits I can clearly see, rmove and roughen up to bare metal and then coat with a zinc primer and then silver again. The bits I know I will struggle to get to bare metal eg where it contacts the floor pan etc, I will just try and brush off the loose rust and then blast again with the degreaser and pressure washer and paint with por 15 in black followed by silver paint on top. The black is to see if the top coat has been breached.
I haven't as yet got a plan for areas I cannot get my paint brush onto or access as yet to rmove rust but open to ideas.
I have bought some waxoyl for another car and ever gout round to using it and I believe that may be black. This would no doubt mess up my plan for having a nice shiny underside where I can see rust spots etc so a clear wax suggestion would be appreciate for the inner chasis bits.
I am not sure what temperture the exhausts get to but I figure I could paint what I could see in some sort of heat resistant paint (for prettiness).
These are my thoughts so far and they have come along some distance from my first crazy thoughts of using a wire brush to rmove the rust. I am open to all suggestions sceptical for give it to the professionals as were is the fun in that, even if you lose.
Love this forum by the way.