Monday, June 24, 2013

The Blue Plague

There is not much to report from this weekend's build process. It was pretty hot and the weekend was predominantly filled with alternative activities like early morning hiking and such, so there was only limited time to work on what I consider to eventually become a plane.
I received a few more parts for completing the build. Among them was the engraved N-number plaque and the gear leg and transition fairings that I plan to add after certification. As a matter of fact, I am planning to trim and install them before certification while I still have the plane in the carport as I deem this to be easier to do at home than at the hangar. I will remove the fairings for certification and then put them back on afterwards.

N-number plaque (about 2"x1")




One problem I ran into this weekend was a self-inflicted one that many had warned me about earlier. It wasn't an issue when I had first read about the Blue Plague and I thought then that these guys were just unlucky or received a bad batch. The issue is the blue vinyl that protects the sheet aluminum from scratches.
I had read that if left on, this vinyl would become a pain in the builder's behind to remove from said sheet aluminum, to the extend that many hours would eventually go into the removal.
Back when I read this, I had checked on my vinyl coatings and found them all pretty easy to lift off the surfaces still and I remember that I repeated this check about once a year during the build process. It was no issue until this summer and I assume this is related to me changing the position of the plane in the car port. I had pushed the plane backwards quite significantly late last year when I started installing the engine to get more room in the front area while working on the engine. That move caused the aft section to get almost pushed outside the carport and it was since exposed to the searing Arizona sun a lot longer during the days than ever before.
UV light kills any softeners added to plastics and the result was that on the areas that were exposed to the sun longest, the vinyl would not peel off any longer but only break off in small chips. That makes it almost impossible to remove the coating in a reasonable amount of time and I ended up scraping it off in these parts with the help of plastic scrapers and finger nails. This is indeed a very time consuming and rather frustrating work and this is when I remembered the warnings I had read years ago about the Blue Plague.
This is even more frustrating as I had decided to leave the majority of the vinyl on the sheet metal to protect it from scratches and then ended up creating much more scratched area due to the plastic scraper used to remove the protective coating than removing it early on could have ever left me with.

These pictures are taken AFTER the scraping. See the close-up on the left side and compare that to the right side which is still shiny as this side was less exposed to the sun.




The lesson that was learned from this is to not worry about scratches on the sheet metal and just remove it all at the time of riveting. It will look better in the end that way and with less buffing. Most of us paint the aluminum anyway and the sheet metal will get scratched up as a preparation for the paint, so there is no reason to be too protective.

With the help of my wife, we were able to remove the broken up patches of resilient vinyl from the tail cone in long scraping session and I will remove the rest on the frontal areas when I get home from the paying job tonight.
Also, the sealants all arrived and I patch up those rivets and holes on the firewall to seal them off in one of the next sessions.

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