What is this stuff... and how to remove it?

**kthelen** · 07-23-2017, 01:02 AM

Quick background: I'm a bit of a newb - or at least, certainly not a detailing pro. I have a tendency towards rescuing neglected old cars with mechanical potential, getting them roadworthy, and then applying my limited detailing skills to make them presentable for my "daily driver" uses.

This is the latest, a 1977 Chevy Van. It was originally from the Seattle area, but spent a couple years sitting outdoors here in Minnesota before I got my hands on it. The paint is a metallic root-beer type color, factory original. It was very dirty with a good deal of oxidation, and the beginnings of some surface rust as well.

The cornerstone of my (very limited) detailing arsenal is a Porter-Cable 7346 DA. My go-to "first step" pairing of a Porter-Cable branded foam pad and Meguiars' Rubbing Compound yielded good results on every panel... with one exception.

On the sliding door, there were two "stripes" that appeared nearly white in color. If this weren't single stage paint, I'd have thought it was clearcoat failure. But, whatever it is, it appears to be on top of the paint. I couldn't budge it with my fingernail. The Rubbing Compound was likewise unpersuasive. The next most aggressive product I had available was Meguiars' #1. That, on a microfiber rag, when hand-applied with considerable pressure in a very small test spot, finally broke through the white crud and exposed what remained of the paint below.

So I popped a microfiber bonnet onto the DA, applied some #1, and gave it a go. Whatever this substance is, it's TOUGH. With the speed set at 4.5 (as high as I dared go... as high as I've ever gone with it, actually) and applying likewise unprecedented amounts of pressure, I finally managed to remove a few square inches of the white stuff - after a good 2 minutes of going at it(!).

I don't want to continue this way. Not only would it take hours at that rate, but it seems a bit dangerous (it would seem rather easy to break through the paint, doing so many no-nos at once).

My questions are...

1) What might this "white stuff" be?
2) What methods/products would you suggest to remove it?

--Keith