Undercoat or Paint?

Unknown

Does anyone have any suggestions about dealing with the underside of a 1940 car? This car is like an average used car from 1950, and has no rust-through, but has light surface rust, smatterings of original paint, and road tar on the underside and inner fenderwells. I do not want to strip and standblast the car. Is there anything, such as parts store undercoating, that would protect without causing the surface rust to continue hidden below the undercoating? Thanks for any suggestions.

Unknown

You could try to clean it up with some light sanding, scraping, solvent cleaning, etc and then appily some POR-15.

[Deleted User]

If not POR-15 Then check with Eastwood, they have a similar product.

EssexAdv

IF you do use undercoat, you should use rubberized undercoat. This will not a=ttract moisture or crack. The problem wiht the old tar based undercoat is taht it cracks and watter gets under the undercoat and promotes rust. Not a good thing. An even better idea, if you are not worried about authinticty would be ti use modern undrercoating. Any good modern body shop can do the job for a reasonable price