My understanding from talking to Dave at the Por15 Depot (great guy!) is that any surface with tooth is great, sandblasted is perfect. I only used metal ready and marine clean on anything that wasn't sandblasted (smooth) so it would etch the surface and be clean.
I disassembled and sand blasted my entire Bronco with a $69 eBay sandblaster, then spraying everything with Grey POR15... I purchased the grey so I would have some color contrast on the chasis where I'm painting it with Black Chassis Coat, and on the frame where I'm painting with Black Coat.
For the body panels, I purchased Tie-Coat so I have a buildable/sandable primer that will adhear well to the POR 15 and allow me to top-coat with their Hard-Nose paint.
The axels, drive-shafts, radius arms, and smaller items I did with a brush rather than deal with the masking... The products are self-leveling and look like they were sprayed. I just finished the body work and spraying the final coat of primer and will post the pics over the weekend.
Here's the Info. I received from Dave:
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Planet Bronco:
Dave,
I just started my frame up and need some help with quantities...
Frame: POR15 + Black Coat
Axles: POR15 + Black Coat
Engine Compartment & Undercarriage: POR 15 + Chassis Coat (Will this withstand the heat?)
Dave:
Ok, get the 4 quart special of POR-15
1 quart of each for BLACKCOTE and CHASSIS COAT.
The Chassis coat will handle the engine area fine as long as there is no direct contact with the manifolds.
Planet Bronco:
Body: Hardnose (Rhinolined interior, won't need paint).
Body/Frame will be prepared through sandblasting, so also let me know what recommendations/quantities you recommend on prep products.
Dave:
Depends on the surface area. I'd say a Gallon would be fine, maybe less. But Im not sure what surface area you are looking at here.
As far as prep products, its your call. I normally get same amount of product in Metal ready and MARINE CLEAN as I do POR-15. If I have 4 quarts of POR-15 I get a gallon of METAL READY. You have to notice two quarts of METAL-READY cost $1.25 more then if you buy a single gallon.