Disassembly was straightforward. Some heat and scrapers were used to help coax the pieces apart. It appears the original sealant may have been a polysulfide.
The pieces cleaned up nicely using a scraper, Scotch pads, and Citrasolv. Brasso removed any residual rust discoloration.
I decided to experiment and try butyl tape for the re-sealing. I’m a big fan of butyl tape, though it works best when the parts will be held together in compression (i.e. by use of fasteners). In this case, there’s nothing explicitly holding the parts in compression, although there is a slight bit of compression when the window is dogged shut, from the foam gasket pushing into the window frame.
I used one strip of butyl tape on the inner frame, one on the outer frame, and one around the edge of the glass.
Re-sealing went smoothly, but required several rounds of squeezing in a vise to get the butyl tape adhered to and squeezing out of all parts.
Also, the frame parts were not perfectly even (as in, somewhat bent). This made the use of butyl tape a little tricky. Polysulfide would shine in this kind of scenario, so perhaps that’s why it was used to begin with.
Anyone have experience with butyl tape for this application? Please let me know in the comments.