New paint over glazing cracking
I am in the end stage of reglazing a few old windows on our house in Vermont. These windows were installed in new construction in 1938. After figuring out how to remove the windows (took some doing) I have found they were pretty nicely made double hung 6 over 6's. I found some manufacturers marks indicating they were Montgomery Ward's windows. Interestingly, the counter balance are springs in channels on the inside of the windows, and more importantly, the windows had metal weather stripping/tracks on the sides which are so good at preventing drafts, I don't think they can be improved. Not a feature I anticipated, and one that took a while to figure out since the weather stripping channels must be slipped out of the sash before the window will come out.
I spent considerable time removing all the old glazing, prepping the frames, and reglazing the windows. I used an alkyd primer, then the glazing compound. I then let the windows sit for 2 weeks to allow the glazing compound to skim over. I thought this was sufficient, but may have been wrong as it has rained here almost every day the past month and has been unseasonably cool and damp. I then used the alkyd primer over the window frames and glazing compound, let this dry overnight, then put one coat of satin latex over this. I went out tonight to put another coat of latex paint on and found that several windows, but not all, exhibited generalized cracking. This is truly disconcerting given the amount of time already invested in reglazing these windows.
So, does anyone know what may be going on?? The paint seems to be adhering fine to the primer and not peeling up. I am guessing that the glazing is either off gassing or moving (expanding??). I really do not want to remove the new glazing and start over. If I wait for a while (a month?? more???) then put another coat or two of paint on, will I be OK, I did this same process on a bunch of windows last year and had no problem. Anyone have a clue??
Thanks in advance