Technical What's the best chassis paint?

I’m clueless, what’s Raptor? Got a picture of the can?

 

It’s brand name for a 2 part bed liner.

this is another brand of 2k bed liner I sprayed a couple weeks ago

 

I don't display my cars with mirrors under them or drive on salted roads, so the undersides get a coat of whatever I have on hand, applied with a brush. Brushing allows you to work the paint into the nooks and crannies well. I find that urethane seam sealers adhere better to these areas with a brushed surface. In recent years I have been using Zero Rust (Rust Bullet), Armor Coat , Impervo Alkyd marine enamel and my favorite Interlux Marine Enamel. The last two being on the pricey side but very tough and durable.
I have some POR-15 that is at least 15 years old, seems to still do the job but not my favorite. I'm just using it up. Guess it just depends on your cars intended use, place of storage and budget on what to apply.
In the pic, epoxy primer was brushed on blasted metal then brushed with Interlux Marine Enamel. Not shown, afterwards it was urethane seam sealed followed by a second coat of Interlux enamel. Not pretty but will definitely out last me and nobody ever sees it anyhow.

 

Krylon on the fender well and frame after a couple years.

 

@gimpyshotrods, you and @HOTRODPRIMER just painted a picture that I can't unsee. And I thought you had no sense of humor

 

I agree POR-15 has a lot to hate about it and has limitations. However, all those over rust paints are indeed super tough. Fully cured they hardly even chip. If I didn't have it already I'd look at something else. My sheet metal underneath will get rubberized, the tool box area will get bedliner. What I don't like about bedliner on the outside it will get permanent dirt over time, less than 2 years. My truck looks like 50 year old tires in the bed and no hope of clean again. Tough as fuck, but dirty.

However another bedliner use, makes a good running board cover if sanded smooth and painted. Seen a few, not bad, seems easy to maintain. I know, I ramble sometimes.

 

I just painted my chassis and suspension with the master series paints by brushing. I love the aluminum Ed undercoat but am on the fence with the ag111 top coat. It’s nice any thick but seems to chip under impact.

 

I've used POR-15 with great success. Mostly suspension parts and battery tray. I'd brush on it the part, wait about an hour for the POR-15 to get tacky, then spray rattle can Rustoleum in satin black OVER the part and let the whole thing dry.
Nowadays, most parts get shipped off to the powder-coater.....

 

I have always used high quality automotive paints for my chassis. My son is building a 53 F100 and he is on a budget. We went to the local farm supply store and bought a gallon of implement black enamel and added hardner to it to spray the chassis and he sprayed it himself. I turned out awesome and he is proud of the job he did. Smooth and no runs.

 

My OT got the underside of car blasted on rotisserie, epoxy primed, raptor, urethane chassis topcoat.

My daily driver truck got air chiseled, wire wheeled, phosphoric acid etched, and brushed with epoxy on frame and rustoleum with hardener on the body. Month layer shot the whole underside with boiled linseed oil.

Just depends if it's apart or together - how much protection I feel is appropriate for that vehicle.

* an undercoating schutz gun will shoot all the way down an inner rocker panel if you hook it to 60 lbs of air.