What type of sander are you using?
If you want to strip paint you should have a "TRUE" da sander that is capable of being locked into different modes. There would be a weight on the bottom of the sander that you lock into place which changes the rotational pattern of the sander.
You can put into a more aggressive grinder mode which when equipped with 80 grit should have those parts stripped in no time flat.
A "TRUE" da sander would be like the DA model from National Detroit. I have this sander, it's the industry standard in da sanders.
http://www.google.com/products/catal...d=0CD8Q8gIwAw#
I used this when I had to strip an entire 2004 F150 crew cab. Equipped with some 180 grit I could do the outside of the door in about 10 mins. The truck also had three paint jobs on it.
Ingersoll Rand 313 high speed sander
