Undercarriage Prep for aundercoating

In preparing the underside to have it fluid filmed. I plan to remove the spare wheel, front splash shields. Anything else or are the fronts even required?

Also I was going to pass the wire brush/wheel in my die grinder in the below frame to break some loose rust off should I spray anything on there prior to the undercoat? Any sort of paint? Or just leave as it and have it undercoated.

 

Depending on the condition, maybe some POR 15 is places.

I would remove all the skid plates. Make sure you use a wand and get inside every frame hole you can, not just the exterior.

 

first rusted out front skid plate. then fuel tank skid plate. then exhaust hi-temp. shields fall off. after that frame develops additional ventilation holes (and additional AC drain hole)

 

Great info. I guess the skid can always be easily taken off and painted? Not sure if the fuel tank one involves dropping the tank, but sounds like something that could be addressed.

The heat shields, every car has that lol. Cheap metal.

What is this ventilation hole due to AC drain? Where is this and whats the fix?

I was thinking of just spraying the underside with rustoleum black?

 

AC drain just above frame. add hose down to go around and discharge below frame. if you not spraying inside frame, everything painting frame outside is pretty useless

 

I guess my question was for the exterior facing sides etc and where the welds are. The interior of the frame is going to get coated using fluid film.

I have the little 20” hose with 360degree tip that mounts onto a can.. but it makes a total mess. It don’t work worth crap, so I’m going to pay someone to spray the fluid film. Before they do that, I was asking about the outter faces..