John Rumm wrote:

First time I tried it, I got about half way down a 4' chase in new
plaster before I realised I could not see my hands 1' in front of my
face anymore!

I would not repeat that exercise in an inhabited building again!

Downstairs of house was almost entirely out of action, I waited for a
windy day, wedged open front door, back door, and internal doors thenlet
rip with the AG, shopped out a full height breeze block wall in the
porch, and "chased" all the drops for re-wiring the kitchen, looked like
smoke belching out of kitchen door ...