Just replaced my 1966 Columbia C26 portals
I know this thread is a little old. But I just finished replacing my portals. They were leaking and clouded. I removed the frames and the old glass. I took one of each shape of window and a frame to my local glass shop. For about $300.00 he cut new glass and supplied me with the new rubber seals. The new glass is thicker than the original so make sure you get the right size. With a lot of patience and some Dawn soap as lube, I was able to get the glass back in the frames. Butyle tape from the local RV repair shop is the only thing to use for mounting the frames. Be sure and keep the two frame halves and inside ring grouped together for each window. It will make it much easier getting the screw holes to line up when putting it back together. I am now watertight and can see.