When I work inside I use a ventilator from Harbor Freight with the duct attachment.
It works fine in my opinion, I know what it feels like to get sick from fumes and I never feel that with this. It is loud, in nice weather I sit the ventilator out side just outside the window on a table and the run the duct deal through the window, propped up in front of the flame. I have a tarp deal I rigged up for the open window around the duck.
Some people will say this is not a good set up but like I said, I've never been sick from fumes using it...
http://www.harborfreight.com/8-inch-...tor-97762.html
http://www.harborfreight.com/8-inch-...uct-97763.html