"JohnF" wrote in message
...
I looked into the "smoke tubes" from Grainger but they're $100.00
for
a kit. I know there is something cheap and relatively safe (can't
kill
anyone except management) I could use to figure out air flow in the
shop.

Ideas?

JohnF

They also make small squeeze bottles (kinda like the ones eye drops or
nasal spray comes in) with silica powder. I would imagine talc or
carpenters chalk would work, too.

Lots of other good suggestions have been posted