Windhield

 It's been raining so I can't paint the tailwheel parts.  Instead I've selected the windshield from the never ending pile of parts needing some work.  The Skylight windows and the Windshield were sealed in with RTV at some point, what a mess.  The window frames were easy to clean up because they're aluminum and stronger solvents like MEK can be used to clean off any residue.  The plastic windows can not be cleaned this way.  The Internet was useless for finding a solution.  Nothing out there seems to be safe for plastics.

 I finally realized I'll just scrape off the RTV with a razor blade and pocket knife and then polish the areas to remove as much of the RTV as possible.  The correct way to mount the windshield is to glue a 2-3/4" wide strip of 1/16" thick SAE F-55 Felt to the edge of the windshield and push the windshield into the retainers.  I still don't know what glue to use to hold the felt to the plastic.  All this allows the windshield to move as the plane flexes, which all structures do under load.

Along with RTV some of the edges had residue from friction tape as well as the original glue used to hold the felt.  The important thing is all this is hidden in the retaining strips so it doesn't have to look perfect. By holding the razor blade or knife at a shallow angle so it shears off the RTV without cutting into the plastic it works fine.  You don't want to cut the plastic in a way that might cause a future crack so you don't want any sharp edge scratching the plastic.  Using the curved area of the pocket knife blade solves this problem.

With the razor blade you need to hold it between thumb and fore fingers to give it a slight bend and then work in the middle of that bend.  That way the sharp corners can't scratch the plastic.  The razor blade works fine on flat or convex (outside) areas.  I use the knife in other areas.  The razor is nice because instead of re-sharpening it you just throw it away and get a fresh one.  The important lesson is never use RTV.  Clearly I could buy a new windshield for $250 and skylight windows for $35 each.  It's nice to be able to use parts which are perfectly functional instead of replacing them.