The previous owner had some sort of rubberized undercoating applied to the undercarriage but because it wasn't prepped correctly (I assume, although people keep saying that the rubberized undercoating is **** anyway) water got in and it's starting to peel. The chassis is still solid, only surface rust with minor pitting in some areas. Not to bad for a car that spent all of its life in rainy Scotland! I have been trying to remove it using only manual tools like a scraper and a wire brush but it is taking forever and I want to try using a different method/tools that works faster. I was wondering if any of you had any ideas or recommendations. Would a multi-tool with a scraper attachment do the job well? I briefly tried a die grinder with a wire wheel attachment but it wasn't great. I was also thinking about using a pressure washer but I dont't want to get water everywhere or worse, break any seals. I also thought of brushing in some mineral spirit, which seems to dissolve it, but again I don't want to inadvertently damage something else.

By the way, the plan is after I remove the rubberized undercoating and got the chassis all clean and degreased, I will apply POR15 Metal Prep, which is essentially phosphoric acid + zinc additives to cover the surface of the metal in a rust preventative zinc phosphate coating. After that I will spray either the Lanolin-based Fluid Film or the Cosmoline-like LPS 3. Any thoughts on that?

Thanks!

 

I use a pressure washer with 180* water.

Easy off oven cleaner
wire brush on a 4” grinder.

step 1
wire brush area to scuff coated surface

step 2
pressure wash to get surfaces to be cleaned HOT

step 3
cover area to be stripped with Easy Off oven cleaner, let soak for 15 minutes or until coating/paint bubbles

step 4
pressure wash with hot.

that should take you to bare metal with 1 or 2 applications.

obviously do not get Easy Off on paint you do not want removed.


FYI, Easy Off is a sodium hydroxide based cleaner. Aka Lye

 

Personally i hate the look of Por15

I use a self etching primer on the bare metal and then paint with satin black.

Imho, rustoleum brand rattle cans are the best commonly available paint.

 

I am only gonna use their Metal Prep product, not the main coating.

 

Thanks for the tip! I'll see if I can get my hands on a similar product here in the UK.

 

I removed the undercoating from the rear inner aprons on mine with a heat gun and some of those plastic pry tools. They were stiff enough to not flex, but didn't seem to gouge.