Thanks Gary. Made a window out of 1/8 lexan last night, made it about 6 in. longer than what was in it so it would extend past an area on the guides that was damaged by the thick plexiglass that was previously in it. Works pretty good ,but of course won't open fully now, but much better than the way it was. Is there supposed to be any sort latch to hold the window in the closed position or is friction supposed to do the job? Rich