| Undercoating removal is a time-consuming less than glamorous task. Complete removal isnít necessary in most cases. For sandblasting or dipping, the bulk of the undercoating needs to be removed and some leftover residue is not a problem. If you plan to refinish the areas without dipping or sandblasting, then some follow-up cleaning will be needed with a solvent cleaner such as wax & grease remover.
One of the methods Iíve heard of is using aerosol oven cleaner products to soften it first before scraping it off. This one doesnít work!
Another one Iíd never recommend is that of soaking the undercoating with kerosene or a similar flammable liquid and burning it offÖyikes!
The 2 best methods Iíve found are to #1: heat with a propane or oxy-acetylene torch and scrape with a putty knife and various smaller special shapes that can be fabricated from sheet steel for various areas. This technique is about the fastest, however will produce lots of toxic fumes and smoke so wearing a carbon cartridge mask is highly recommended!!! Also care must be taken on external panels such as quarters or fenders, not to get the metal too hot and cause warpage.
#2 method: Similar, however, for the heat source an industrial heat gun is used and a pneumatic scraper is the tool for removal. While a bit slower, the fumes are greatly reduced and warpage is much less likely. The most efficient way to work with the heat is to preheat the area just ahead of where the air scraper is used. This has become my preferred method.