I have given up trying to "seal" the windows. I have tried sealing between the bus frame and the window frame, sealing between the window frame and the glass, sealing the channels that the top window slides into, sealing space above the top window, and sealing the horizontal gap between the top and bottom window. I am done.
I have started removing windows that I don't want and putting a piece of sheet metal in the opening, then sealing that. Problem solved.
However, there are places where I want windows. I like the "school bus look" and want to keep the double pane look. They may or may not open, I am open to either.
I would like to "rebuild" the windows and then reinstall them, I would prefer to use the same glass since it is all in good shape and I have the aluminum frames.
The difference between my old and "rebuilt" windows will be that they will not have the channels on the side and there will not be a gap between the sliding and affixed panes of glass.
I am looking for a thread, tutorial, or advice from someone who has done this.
If I can't do this, I will be purchasing new windows (probably from an RV supply).