Undercoating removal -

[Blue666(2)]

What is the best way to remove 50 year old undercoating?

I don't have the shop or compressor to be able to sand blast. I'll be working with an angle grinder. The wire wheel does not seem to make a dent.

Should I get a 7" angle grinder?

Then again, I will be welding in some new panels, painting with POR15 and undercoating everything, do I really need to take off the old stuff if it is on so well?

All opinions or experience appreciated. Thanks.

Blue666(2)