In article .com,
"kmillar" writes:

How safe is it to use a blow torch in this confined space? (About 18
inches of verticle space benathe the floors). Apart from the obvious
need to not set the house on fire, I'm more interested in the fumes
given off by the blow lamp. What can I do about those?

I've done plenty of this and it hasn't been a problem.
I have only lit the blowlamp when I need to use it, which
means it will only operate upright as the preheat coil
doesn't get a chance to get to operating temperature, but
that's the only way up I need to use it under the floor.
It was not so much the fumes I was worried about as knocking
it over -- much of the underfloor space in my house seems to
have been used as the dumping area for a previously removed
smashed up floor together with wood shavings presumably left
from when the house was built, and I was concerned about
setting it alight. I took a 1kg dry powder extinguisher
with me under the floor too. It might be a good idea to have
someone else in the house too to keep an eye out incase you
get into some difficulty.

The other thing is remembering to take everything with you
when go down there. It's annoying to spend 5 minutes wriggling
from one end of the house to the other on your belly (through
the small holes someone else has fortunately already knocked
through the sleeper walls) only to find you've forgotten the
solder or flux or steel wool, and you've got to go all the
way back again!

One place I did notice the effect of the fumes was when
soldering in the back of a kitchen cupboard. It wasn't the
effect they had on me, but that they caused the 20 or so
spiders in the cupboard (the harvester things with long legs)
to all come running out at the same instant, all straight
into my face. Fortunately I don't have a problem with spiders,
but even so, it's not really what you want to happen when you
have a lighted blowlamp in hand.

--
Andrew Gabriel