Looking to seal up trunk floor.

[80Grand_LeMans]

I recently cut out my spare tire tub because of a nasty hole in the bottom of it. I covered the hole so now my trunk is all flat. I want to stop all the rust and just make it super solid. It can look as ugly as needed because im going to cover it up anyway. There are a couple tiny rust holes about the size of a dime, maybe, and one big rusted area up by the back of the rear seat. My friends dad said there is this stuff by rustoleum(???) that soaks into the rust and kind of just creates a big mass that doesnt rust anymore or something. I also had someone else say roofing tar works really good. And I was also thinking truck bedliner but i heard its pretty expensive.

My main goal is to get it to not rust anymore and just give it a nice protective coating. I have already grinded down the whole trunk to remove anything that could be lifted up. I want to start this tomorrow so I hope I can get some tips real quick. Also any specific procedures like prepping the area first and how much to coat it with.

Here is a quick picture of after it was grinded (first time ever working on car, please not too much criticism on the metal plate and such, it works, lol):

Thanks.

 

[DOUG213XRJ]

POR15.

 

[NEW2MALIBU]

I used Por-15 and it works great on the rusted areas, although the clean metal needs to be prepped for Por-15. (Zinc Phosphate I believe) Use Por-15 on the rusted areas and spray bombs on the clean stuff. As for where you installed the sheetmetal to cover the spare hole just go to the auto parts and get seam sealer, it applies with a putty knife and then use a brush to go over it and get it in all the cracks. Hope this helps.