Undercoating?

I am busy grinding and cutting away my trunk floor and am wondering about the undercoating below the trunk.



and a close up view...



Looking at the right side of the trunk floor, where the new trunk panel will sit on that cleaned off ledge and be welded and seamed in. Looking below that edge you can see all the crud and mostly rubber undercoating that I am grinding away to leave a clean edge to weld. Once done and the trunk is all installed, that will be an area that will have primer and paint to seal it, but should I re-undercoat it again?

Is undercoating a good thing or bad thing as far as protecting the metal? This is just a cruiser car, not show car, not matching numbers, just want to enjoy it.

SO........ under coat or not?

Thanks
Jon

 

i re-undercoated my 72 gs with rattle can undecoating, when we the car on stands some 9 years ago.
certainly, it will not hurt anything to undercoat.

 

While you have the pan out, use phosphoric acid like I show in my article to rustproof the gas tank supports. Rubberized undercoating at Autozone, Professional Label works great.....use it as a base on the trunk pan and then use NAPA trunk splatter coat DM109 for a final finish.

 

Undercoating is a good thing, mostly because:

It acts as an insulator, to reduce road noise & vibration from underneath the vehicle.
It protects & prolongs the undercarriage from road debris that would otherwise damage the bare metal floorpans.

Among other reasons, but even a few are good enough reason to want to add undercoating, to preserve your project for as long as you intend to enjoy it, without having to repair it prematurely.:beer

 

I have the new gas tank supports that came with my trunk floor kit so the one you see will be coming out too. I have the left side out and pretty much ready to go, but left the right side as a base for what height to set it.

I have the phosphoric acid to use in other places and have seen different opinions on the clean up.
Some say keep wet and wipe down with wet rag.
Some say let dry and wipe off with lacquer thinner rag.
Others say hose down completely and dry under heat.

I would think that wiping down with a baking soda and water solution would neutralize the acid but I haven't seen anybody recommend that surprisingly.

I will be spraying the entire inside of trunk and car with Rust Bullet after all the floors are fixed and blasting some undercoating on below based on the responses here.