Grinding The Paint Off

I started on the next two panels today.  Here is what I am up against.  Kinda peeling huh?  So I use a good metal scraper at first to get all the loose stuff off.  Then I have to hit it with the grinder.

And when I say grinder I mean grinder not a sander.  A sander is just to light duty to get all the old paint off.  I think there is still paint on these panels from the original paint job which was done in 1925.  The entire resort was remodeled in 1992 but I can tell that these panels were not stripped down all the way then.  Which is probably why its peeling so bad now.  So what I am doing is taking all the paint off down to the original surface and starting over from scratch.  I spent all day grinding paint off and got both panels ready to prime.  The grinder is a really powerful tool so I have to be careful about what I am doing.
The top part of this next panel is done and ready to prime.  What you see is about how much area I can work on at a time until I have to move the swing stage down a little more.  Notice how the design is almost a white and the background color is redish.  The design is actually a different material than what the background material is.  The design is a plaster and the background is a concrete.  Because the design is a plaster I have to be real careful with the grinder I could easily grind the plaster right off so I need a light touch, enough pressure to get the paint but leave the plaster.  The concrete is a harder substrate but I still have made some gouges in it with the grinder so even with that I need to be careful.  I got both panels looking like the top of this one below and ready to prime but it started to rain and I had to knock off for the day.  Back at it Monday.