On Tuesday, November 11, 2014 8:19:47 AM UTC-5, TimR wrote:
On Monday, November 10, 2014 11:17:17 PM UTC-5, nestork wrote:

Now, putty was popular decades ago before there were high quality
caulks. So, what I tell people that are replacing panes in wooden
windows that are held in place with putty is to:
1. remove the putty,
2. pull out the glazing points,
3. replace the glass,
4. push the glazing points back in and
5. Use a high quality caulk like Kop-R-Lastic instead of putty, and
6. Paint both the wood and the caulk once the caulk is fully cured.

This window is clearly steel. So I'm not sure how it's held in place but probably no glazier points. It looks like a wedge of putty but it's suspiciously even and smooth. I'll see more when I get it out. It has been painted, fairly sloppily.

I replaced glass in a couple of steel-frame windows many years ago. My memory is a bit fuzzy, but I recall that the frames had channels in them. There were spring clips that fit into the channels to hold the glass tight with their tension, after which I puttied over the clips. If you remove the putty on your windows, you will probably find the spring clips buried within.

Paul