On Sun, 4 Jul 2010 01:27:30 +0100, Spamlet wrote:

I've never managed to get paint off masonry with a blowtorch/heatgun.
Not entirely sure why: suspect that the surface is too rough and porous,
so the solvent/wood resin vapours cannot build up to form the blisters
that lift the paint.

Or you just can't get the paint hot enough for long enough when on a
great big masonary heatsink? At least not without a BFO "line burner"
type blow lamp.

Not a job that I would want to be lumbered with, and I would imagine the
pros would bead blast. You might be able to clean it up with a power
washer, before repainting.

See another recent thread. Small domestic pressure washer and
"dirtblaster" lance certainly got a lot of the flaking paint of our
walls on a test run. A lot quicker and with far less effort than
scraping or wire brush. Leaving it for a few days after the initial
going over then having another may be benificial. Some of the paint
that didn't come off in the test run is now looser than it was.

--
Cheers
Dave.