I need to paint the clapboards on our dormers. The paint is oil-base,
~20 years old. After I scrape and sand, I can often still catch an edge
of the scraped area, and pop off another small-ish patch of paint. That
it 'pops' makes me wonder if it's not really well-bonded to the wood.

So, I'm thinking I should get down to bare wood, at least in some areas.
I'd be happy to be talked out of that.

Thanks