Help For Making Windows

You can use acetate or the clear packaging from toys and such. I'm not real sure what all is available in the UK compared to here. Hopefully this helps a little!

Are they diecast or plastic builds that you're trying to replace windows on?

I agree with JB, but it is very hard to get anything to work if the windows are curved. Acetate works good for side windows. I use it a lot in my gasser builds. If you get something to work let us know.

I don't know what ecetate is, but i have used the clear plastic that comes when you buy a new shirt etc, as for curved windows, glue it in the center, next day, go out a bit further, and repeat
each day after it has dried solid, you will be amazed what you can do with it.

I usually use a container from cookies and such. Stick a piece of painters tape to the inside of the window opening and trace the outline with a sharpie or pencil. Add a 3mm or 1/8" margin. Transfer this pattern to your plastic and trim carefully until you have a good fit. You can use white based glues to temporarily hold them in place, but epoxy is the permanent way to install them. Do not use super clue, these usually cause fogging.