Where you can, apply heat from inside the car. You don't need to heat the undercoating all the way through, you just need to break the bond it has to the sheet metal. Two people works great for this job. One to scrape, while the other heats. Use mineral spirits, or engine degreaser for the residue.

I was able to get it off with sandblaster using black beauty fine grit for media and 75psi. I did a quick pass with a scraper then hit it with the blaster. Very nasty job, used a full face mask respirator and a bunny suit just in case the undercoating was made up of nasty stuff.

The cheapest and easiest solution that I've found are the 'roto strippers' that you can buy at hardware stores and on eBay.

The way to do this is to use Gunk Engine De-greaser. Spray it into a contrainer and use a brush to work it into the undercoating.

Keep the area wet and use a poly tarp under the car. The undercoating will practically scrape off like butter.

I did my '66 Dodge Monaco this way, and I had previously tried all of the above mentioned methods, but none worked as good as this.

Brad
1966 Dodge MOnaco (Canadian Built)

Challenger1 , Is a hotsey the same thing as the steam pressure washer?

I just rented one for work. It sprayed hot water and the output was around 2500 psi.

Are you using something different?


Thanks