The second double pane window is apart! Yay! Elapsed time from start to moderately clean glass is two hours. Timeline so far is:
15 minutes to get the frame off
45 minutes to get the glass apart
40 minutes to get most (not all) of the butyl off the inner glass (gag, MEK brain damage...)
20 minutes to get the film and adhesive off the outer glass
Tools are as shown--mallet, wood block, scraper, 1/8" drill, many thin wood wedges, MEK, paper towls, scratchy sponge (the non-scratch kind), and scrap chisel.
1. Drill out rivets that hold the fame together
2. Cut the black gasket at the frame joint (you might want to remove it completely prior to separating the frame--it will make removal much easier.) If you don't cut it you won't be able to figure out why the frame won't come apart!
3. Use the wood block and mallet to tap the frame off the glass. The two pieces can only move in the left and right direction until the square steel rod is out of the frame channel on top and bottom.
4. Peel off the gasket
5. Peel off the silver tape or cut it all the way around between the two panes. This stuff is like silver duct tape and it adheres to the glass like crazy.
6. Start gently tapping the wedges between the glass. I started at a corner and went along the long edge. I think the glass is flexible enough to bend 1/8" at a time, but I tried to keep it nearer 1/16". In some places the butyl comes right off one pane or the other for 4-6" at a time, but in other places it took a wedge every 2". For this window, the corners were very tough to get apart.
7. Work your way around the whole circumference. I used a heat gun in a couple of places--not sure how much it contributed to success but I'm glad I did it.
8. You may have to remove some lengths of butyl before you can actually separate the glass. The durn stuff is so sticky that even though you can see that the butyl has let go of one side or the other, just a slight touch and you've got several lbs of adhesion. I used a wedge to pry out a small length, then pulled on it and got quite a bit more to follow.
9. Scrape as much butyl off the inner pane as possible. This pane is a pain to clean. MEK will disolve the butyl if the remainder thin. Lacquer thinner works to some extent, also. Acetone does nothing.
10. Use the scraper to attach the film on the outer window. The butyl is onl top of the film, so a good hard scrape will remove the butyl with the film. What's left is the film adhesive, which is water-soluble, Use your non-scratchy scratchy sponge to get it off.
Youcan tell this is an "after" photo with the butyl mostly removed.
One comment about the "you can't take it apart because you'll introduce humid air..." remark. Probably true, but a few drops of condensation can't look as bad as these windows do now. Plus, the absolute level of water in the air when it's cold is low. You can fix this problem by throwing a few beads of desicant between the panes (that's what those little gold beads are that you can see in the production windows) as you are closing it up or, if you have access, you can blow some dry nitrogen between them as you're closing. In any event, we are going to find out how bad that problem is pretty soon (one hopes).
Still waiting on the new butyl to arrive,