I just bought 9800B, and was pleased to find out it has Ceconite with Randolph dope system. Not only that, but it was never top coated with polyurethane. I like STITS just fine too, but the following experience this week really opened my eyes.
9800B was recovered in 1992, and had a few cracks in the dope at the windshield and over the tank cover leading edge. Because it was Buterate dope, I was able to use Randolphs Buterate rejuvinator. It softened up the cracked dope, and melted it back down.
Cracks in Polyurethane can't be melted back down.
I'll never use a polyuerthane top coat in the future, that rejuvinator was amazing on 19 year old dope!!
I laid down a boundary of electrical tape on either side of the cracked area, and applied the rejuvinator with a 1" chip brush, returning every few minutes to brush on some more, including into the cracks. after a while the lifted part of the cracks began to soften and bend, eventually they melted completely and flowed back into place. I'm going to follow up with some colored dope to final match, because the white dope over the windshield was applied over the Bahama blue, so it stirred up a little blue tinge, but the dope bond was very satisfactory. Be sure to lightly run a razor down the tape near the edge, then pull up the tape while the dope is soft. I have a slight edge on the repair area, but it is much better than a dope crack. (not sure about when to pull the tape up, I have not tried waiting until the dope sets up first)
I realize that dope won't be as shiney as polyurethane, but original dope & fabric planes were dope covered the same way, so it looks 'right' to me.
The FAA specifically allows these repairs, including tape and small patches. It is so easy and extends the life of the cover.
I was also warned to never allow any silicone based polish, wax, treated rags etc on the dope, as it will ruin the ability to repair it.
1) Brush nothing use the HVLP gun on everything. This is really true on the wings as the light wt fiber show every imperfection. (2) Cover the bottom of the fuselage with the heavy fabric, all the vibration shows up down on the bottom. (3) Get as much help as you can, the wings are very heavy and you must remove them to do the fuselage. (4) Build a wing jig like the factory. Russell W. has great pics and advice on that. (5) I used Jim and Dondi Miller for all my supplies and advice. This was a wise move as he does the Goodyear Blimp. (6) Follow the manual and you'll do fine but don't use a brush except for the PolyTac glue. The day you start put on the fresh air mask and pretend your an Air Force pilot in a closed hangar this s;;; will knock you out. Try it in your house and your toast! I'm proud of myself for doing this and very very few people ever completed a job this intense. My crate looks and flies great and I was it's savior. I'm now involved with a Spartan Exec and we have been on this for 7 months after it left the Waco factory rebuild/repair. We could write a book on this but the work is much easier than the Bellanca recover job. Loving old airplanes has it's price. Lynn the crate my wife calls it 'Jezebel' :shock:
