Hello all, I made some more progress with the pop top this week. The Rustoleum I used to paint the parts with was finally hard enough to allow bench assembly. The piano hinge is now complete and installed on the roof section as is ihe first layer of polycarbonate (translucent central section of the pop up). I'll glue the second layer on this Sunday and then the top will be ready for final installation on the bus. I expect to get the weatherstrip in on Monday so I should be able to do the install on Tuesday.
I am using windshield mastic to hold the plastic in place (polyurethane) and had originally planned to use a "Z" bar as well. However, after doing some testing of the stickiness of the mastic I don't think the "Z" bar is necessary. I glued two pieces of polycarbonate together with a small amount of mastic, let it cure a week and then tried to pull the two plastic pieces apart. I pried and twisted in an effort to break the bond and not until I held one piece in the bench vise and grabbed the other piece with a vice-grip and pulled as hard as I could did I get failure. The bond between the plastic and the mastic held but the plastic material itself finally gave up (see pic).
I also tested how well Rusoleum worked as a substrate for the mastic and discovered that the mastic easily pulled the Rustoleum off its primed new steel base--not a good sign if I want the polycarbonate to stay in place. I talked to the guy at the glass shop where I bought the mastic and he said the best bond would be achieved by bonding the poly directly to bare steel--which is what I did. I am finally ALMOST done with the pop up unless some new devils present themselves