Liquid Windows

I think the product is "Krystal Kleer". It comes in a small plastic bottle and looks like thick white woodworking glue.
I've used it for a lot of things. It makes window panes up to about 3/16" square. Run a line around the inside edge of the hole and then spread a blob across the opening like a soap bubble. Let dry.
Result is not perfect, but looks reasonable. Can't see through it well enough to tell if the inside is detailed.
 
There was an article in an old issue of Model Railroader (Jan.'78-page 106) that had an article on Krystal Kleer-The author raved on it, & told about application techniques. Never tried it myself though.
I'm just getting back into the hobby somewhat after a dormant period of many years-hence the old issue of MR being handy.
 
:thumb: I've used "Micro Kristal Klear" on many occasions and love it. I've used it to install side port holes in F7's and windshields in metal ho scale cars among several other applications. I apply it with a round toothpick. It's made by Microscale, the people that make decals.

Dick
Texas Chief
 
I have used Testors clear parts cement and window maker on several locomotives to make the windows and it works pretty well. it is easy to make the smaller windows, but you have to get a big glob on the brush to get it to work on the front windshields and other larger window openings.