The coating itself is a tar like substance that sticks to the undercarriage components and acts as a barrier to resist salt moisture oxygen and other items that lead to corrosion.
Using roofing tar for undercoating.
You can use a black roofing tar cement asphalt in a gallon container.
Use the broom to clean your roof before applying tar roofing.
Then the roofing tar will fall out.
Probably not a good idea.
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.
Roofing tar takes a lot of heat to put on slops on with a mop gets soft in the summer and can crack in the winter.
Using small amounts at a time apply the roofing tar with your roller in short and smooth strokes.
It s a true temp fix as eventually the entire metal under the patch will rust away.
Problem with roofing tar is the metal continues to rust.
Consider leaving your container of roofing tar in direct sunlight for about an hour.
Use por 15 and fiberglass for a permanent fix.
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.
Rubber coat 57 roof tar.
When there is no debris left you are ready to apply tar to the roof.
The sunlight will thin the tar and make it easier to apply.
I ve got photos attached of my gold award winning undercarriage on our 69 mach1.