Rustproofing my 2021 Force Gurkha's entire body shell & frame

The frame of the 4x4 SUV has poor paint protection. Unlike the body shell, it is not dip-coated but simply painted from the outside without primer.

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Cavity Wax Plan: Since I had already dismantled the interiors planned to cavity wax the entire body shell.

3M cavity wax and the wand is good, though considerably expensive, reach and coverage is unmatched. Waxed full shell including interior tunnels, side fenders, hood and all doors joints.

Top picture: you can see factory waxing in the tunnel between A-pillars, coverage is sparse. The bottom one is after applying cavity wax, ripple as seen via cable camera, coverage was excellent.

Factory waxing in the tunnel between A and B pillar

Tunnel between rear pillars

Frame Rust Proofing: Gurkha's Frame has poor paint protection, unlike the body shell, the frame is not dip coated. It is simply painted from outside without primer, main member internals, cross member internals, under-mount points, etc do not have paint. It was a real pain to do frame rust proofing.

All cross members had rust, this is just a sample, ignore the red color it's due to the phone camera being too close.

Cross member after rust removal, grey or white coating you see is coating left by rust removal acid, this will quickly start rusting if not painted.

Internal of the frames as seen via cable camera, you can see rust, MB like spacer and C-in-C overlap joint as well. Internal of one side of center frame piece was painted though.

Rear-end, this C-in-C overlap extends till the front of the rear wheel arch, it's painted just at the end.

I used RustOust in 50% concentration sprayed throughout via various frame holes and kept it wet for a day, then used a pressure washer with swivel head + zero deg attachment to clean up the rust. (If rust is thick just repeat, if you can reach and scrub that would be good too).

You can see one side of center piece has paint or coating, white/grey is bare metal, poor resolution of cable camera makes it look like paint.

I used 3M underseal with a small quantity of slow curing thinner for better spray/flow inside the frame, 3M underseal has very good adhesion over rust.

Taking a clear pic is hard with a cable camera once the internals are coated black, this one is a phone shot through a paint hole.

3M underseal inside pan-rod mount, those bubbles are weld splatter.

Moved the antenna from glass to here, I like clean glass without any sticker or attachment, only the registration sticker remains.

Waxed side chambers as well, see below.

You can see W463 waxing (yellow stain) in this picture.

Spare Wheel Mount: Looks like the chassis is dip-coated with a wheel mount attached, so the spare wheel mount joint has some bare metal, resulting in rust. Had to clean and paint this patch on both the shell and wheel mount side.

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