Old undercoating removal

The Super 8 was undercoated when new, which is probably why there is little rust in the bed area. I hand scraped the fuel tank before taking it to be cleaned and I don't relish the thought of doing the whole underside that way.I'm wondering what's the best way to remove the old undercoating from the underside of the van?

Sad news is scraping it off is the fastest way. Even sandbasting will not be faster (just bounds off) Some of it will be dried out and come off easy and some won't. I used a heat gun and that speeded it up

I was afraid of that. I spent over 25yrs in the flooring industry, I got pretty good at scrapping old tar base adhesives of from sub floors. Of coarse I wasn't trying to do it over head while laying on my back underneath a van.

Hey Linoman,

Sounds like the undercoat is still pretty good, correct?
Might be worth considering just recoating what is there, just pressure wash the underside, then use mineral spirits and follow up with some black enamel or mild bedliner paint.
I did that on my '61 Falcon and it is still looking great after 4 years...

SDE ~ I will definitely give the underside a through cleaning & inspection of the undercoating before doing any removal. Freshening it up sounds much better to me than scraping the whole thing, especially as I need this to be a driving project sooner than later.

Scraping is it!! I did spray it with "Mr. Muscle" oven cleaner and let it sit for a few days and it did help soften it up a lot.....

Definitely the scraping method is the best....and the most exhausting. We tried sandblasting my '68, and like it was said above, the stuff just bounces off, and makes a mess. Oven cleaner sounds interesting, just be sure to wear a mask and cover all body parts - that stuff is nasty on skin and in your lungs.

I just remembered there is another method if
you live in cold climes. Undercoat chips off
pretty good too. Once you get an edge started
it can be pried and chistled in pretty good sheets.
An air needle scaler tool is good for the nooks
and tight spots.
I don't have the climate here, but have done section
during the winters here (around 30 to 40F a few
nights out of the year...)

...but still wondering if taking it off is necessary.
Maybe some pics of the rust areas. Fix them, then
use etch primer and put new undercoat back on.
Finish the entire area with spray bedliner like
the black Dupli-Color stuff.

The heat gun is really what saved me a ton of time on my 64. Some of that stuff was like iron still.