Following are the steps I'm using in making storms for these windows, which I had made 15 years ago to go in the wall that was repaired because it was rotten from the water eating away at it for years (previous owner).
First I measured the space, bought the wood, cut and mitered it, then routed a channel on the inside edge of the outside of the window with the bit in the lower right of this fuzzy picture (sorry!).
I am a router novice, but am learning. I made two passes a little over 1/8" deep each to make a nice deep shelf for the glass about half-way through the depth of the frame. It ended up being about 1/2" deep.
Then I assembled the frame with glue and corner clamps and then secured it on the back side with flat screw-on corner braces, since I don't have a fancy biscuit-cutter for joining. Note to self: Never use the table saw for mitering again!
After painting an undercoat on the whole frame I purchased glass and put it in with glazier's points. Gotta admit, that routing looks sweet!
Then I smushed glazier's putty around the frame, covering the points. It's ok to be a little messy at this point--just don't get putty all over the glass.
Then take the putty knife--be sure it is not rusty and rough--and start at a corner, tilting it at an angle that meets the top edge of the frame on the other side and is tight to the bottom of the frame on the other. Easier done than said. It is about a 45 degree slant on the knife. Just keep it nice and firm--use two hands if that helps--and slowly drag it to the other corner. At the corner, lift the knife up making a nice bevel in the corner. If your putty is fresh, this will go quickly.
AAAACCCKKKK I don't believe it! I ran out of putty 8 inches from being finished! This was a new 8 oz container and it didn't even do two windows roughly 36" by 34". Must keep that in mind. I'm going out later and was going to stop at Meijer's on my way home, so will have to add another container to the list. It will take days to dry, so adding the final 8" won't be a problem. I have to put another coat of paint on the multi-paned windows anyway and then put the spring bronze weatherstripping around the opening.
I'm going to hold the storms in with hooks and eyes as I don't want to climb a ladder and hang them from the outside, although this would be the best way to do them. These windows are going to be fixed-in-place windows so I'll just have to remove the inside moldings if and when the storms need attention in the future.