I’ve been using homemade under coating

Question:

I have been using an under coating for car and truck bodies that I “invented” back in 1969 or 1970. It’s homebrew undercoating that lasts about 20 years. The prep is just a light scuff sand and wipe down with a clean rag and lacquer thinner on sandblasted metal with a good primer.

Take un-fibered plastic roof cement and the cheapest lacquer thinner you can find, mix it to a consistency that you can blow on the body. For the first coat I use a thinner consistency then wait a few hours and follow up with a thicker coating. I’ve never gone over three coats.

Make sure only the areas you want covered get sprayed because it’s a mess getting this stuff off.

There are many other uses for this coating as well, like on posts that I install into the ground. It works...and it doesn’t break the bank.

Answer:

Your homemade under coating is a good solution to the problem but with a couple of caveats.

As is true with any kind of under coating, it’s essential that the underlying surface be totally clean and dry. If it’s not totally dry you’ll trap corrosion-promoting moisture against the metal you’re trying to protect, and if it’s not completely clean the under coating will not adhere properly.

Also, anyone trying this should be prepared to deal with a considerable mess.

Carefully mask off anything you don’t want the material on and wear a full body paint coverall as well as goggles, gloves and a head sock.

And finally, don’t use your good paint gun to spray the under coating on.