Picked up a piece of Lexan from Home Depot, and ran a trial window (okay, two trial windows) before settling down and turning out a couple of satisfactory replacements. The technique of scoring and snapping the plastic off cleanly momentarily eluded me, but I managed.

I left both windows oversize, and dressed each to fit with a file. One of the measures was missing a retention washer on one side of the window. It also was sans a lid for the reservoir. A quick trip to the local hardware store fixed that up. The pvc plumbing cap fits perfectly, btw, and is easier to use than the brass cap on my other B&M. If you are missing one, get a threaded pvc cap, the unthreaded variety are far too loose.

I also ordered a handful of stainless #6 button head screws. I'm going to replace all the old slotted screws. No particular reason to do so, other than some old buggering of the original screws, I just like the clean appearance of button screws.

The measure in the photo was the one missing parts, it was in slightly rough shape cosmetically. I got the grime off, polished the reservoir a bit, and it should be good to go another 50 years.

Otony