Fumes of putty

Any ventilation is better than none. Putty does not put off a lot of fumes, but they can be nasty... so I would say to do as much ventilation as you call!

"Fumes of Putty" would a good name for a modeling movie! Putty has Tolulene (sp) which is nasty stuff but doesn't give off much odor. Keep a window open and move away from your work, or move your work, until its dry. Nail polish is much nastier but they do make low fume varieties but they don't work as well. Your best bet is to have a secondary place to do major "fumey" work like the basement or garage.

If you have an good paint booth, then do your putty work in it. If you putty somewhere else in the room, the booth will eventually remove the fumes but will take a little longer to vent them.

When I first installed my spray booth I did some experimenting. I found that, with the spray booth operating, that the smoke from a cigerate in an ash try any where within 6 feet of the spray booth went directly to the booth, but a heck of a lot slower than if the ashtray was in the booth. Now if I am doing anything with chemicals on models (gluing, mixing paint, applying putty or brush painting) the fan in the spray booth is running.
Just be smarter than a college professor friend of mine. As I had been extolling the virtues of my spray booth, he decided to get one for himself. The next time I saw him I asked him if he had it yet and if so how did he like it. Yes, he had one and no he didn't like it. Went to his house and discovered the problem immediatly. Seems he had installed it on his desk (no basic problem there). But he had not vented to the outside, just blew it back into the room. Filter took care of the overspray, but not the fumes. At least he was smart enough to wear a respirater but his wife was extremely irritated. Showed him how to correct it and now he loves the thing.