Undercoating spray can be purchased as a diy product but it s tricky to apply so it s best to use this method at the dealership on a new vehicle.
Using roofing tar for undercoating.
You mix the black roofing cement asphalt with mineral spirits to get a brushable consistency and just brush around all the areas on the undercarriage that ford originally brushed it on.
You can use a black roofing tar cement asphalt in a gallon container.
When there is no debris left you are ready to apply tar to the roof.
It s a true temp fix as eventually the entire metal under the patch will rust away.
Using small amounts at a time apply the roofing tar with your roller in short and smooth strokes.
Start in the corner furthest from your ladder.
The sunlight will thin the tar and make it easier to apply.
Problem with roofing tar is the metal continues to rust.
Use por 15 and fiberglass for a permanent fix.
Then the roofing tar will fall out.
The stuff is fine for the top of a flat roof but probably terrible for the bottom of a car.
And can you imagine how hard it would be to take off in a few years.
Rubber coat 57 roof tar.
Consider leaving your container of roofing tar in direct sunlight for about an hour.
Probably not a good idea.
Use the broom to clean your roof before applying tar roofing.