We're (slowly) renovating the sash windows in our house and the current window is causing problems. What should have been a quick job (especially at this time of year!) has turned into a marathon because the putty won't dry.
We had to replace a couple of panes of glass (one was cracked and we broke another when using a heat gun to remove the paint) so we knew it would take a little while. On a previous window the putty took over three weeks to dry enough to paint partly because (as we thought) there was too much oil. So this time we rolled the putty on newspaper first to try to remove the excess oil. It seemed to work, but after two weeks the putty is still soft to the touch.
We've tried standing the windows next to a radiator but all that seemed to do was make it softer (which was obviously going to happen in hindsight).
So given that we don't want to reputty the windows what can we do to speed up the drying process.
We've had to seal off the room and cover the window as best we can in the meantime.
I've found this advice on DoItYourself.com which doesn't really help as it says use other materials!
The answers to this post on DIY-Forums are confusing at best and possibly contradictory as one recommends exposing the putty to moisture(!) to speed the drying process.
Best Answer
Heat will make the putty softer, which is why you can heat it up to remove it. Putty pretty much stays soft for years. Initially, it doesn't really dry out so much as oxidize which forms a skin on it.
If you absolutely must paint it right away, you'll probably has to use one of the latex based glazing compounds. If you want to use a traditional one, paint it as soon as it forms enough of a skin that the paint will stick to it. Also, I think you probably should be using oil based paints, but check the instructions on the putty.
If you let use know specifically which putty you are using, that might help get better answers.