Skim-coating painted plasterboard?
I think this may be one of my first posts, if not my very first one, on Garden Web.
I've got a question on how to proceed re-painting a bedroom. The house was built in 1938, and the walls seem to be made of plasterboard...not exactly drywall, but no lath behind them either. The previous owner used masking tape to mask off 4-inch stripes and paint pink-on-pink stripes in the whole room (latex paint). Each stripe then, because of the tape, has a ridge on the edge. I have tried a belt sander and disc sander to get the ridges down so I can re-paint one solid color, but it is taking forever and also not even going that well. I'll sand till the ridge is gone and discover I've sanded all the way down to plaster in another spot right next to the stripe.
I think it may be better/easier to skim coat the entire room. But I've never done this before and am not sure if I'm about to get into an agonizing project.
What do I need to buy and do? I have a nice wide spreader...do I use drywall mud? How thick - just enough to fill the lows? Is it hard to do smoothly?
Thank you all in advance.