Wednesday, October 7, 2009

Finally getting started!!

So what has happened since my last post?
  • Attended a 2 day EAA Sport Air Sheet Metal workshop
  • Went to my buddy Ron's house to see his workshop and almost completed empennage of his RV7.
  • Spent hours researching primer on the Van's Air Force (VAF) website
  • Made my decision to use self etching primer, instead of alodine, at least for the internal priming
  • Repaired one of my work benches to correct a bow in the table top
  • Officially started working on the horizontal stabilizer on 10-6-2009 - 3 hours last night and 2 hours tonght for a total hobbs time of 5 hours so far.
Details from the above events follow:
For the sheet metal class we built a section resembling an elevator, complete with an inspecton panel and a trim tab. I will upload pics of the fnished project, but I need to pull them off of my cell phone memory first. We had to work in two-person teams, and so only one person got to take the project home with them. I let my partner keep the project, because he had not yet started on a plane yet, and he needed something to allow him to keep dreaming about it. I knew I had the real thing waiting for me at home, so I was OK with giving the project piece to him. The only complaint I had about the class was the time constraint to finish the project. We had to work extremely fast as a team in order to finish it on time.
Seeing Ron's empennage was also a huge plus for me. He showed me his tail pieces, showed me how his workshop is set up, and talked to me about some things to watch out for in the plans. He was finishing up the left elevator, which also contains the trim tab. Ron also attended the workshop that I was at, except he was in the composite class, working with fiberglass and resin, which you need to know how to do to make landing gear fairings and a host of other things.
Primer wars......alodine, acid etch, epoxy-based, self etching, or nothing at all? Those are the choices pretty much. I talked to a rep from Sherwin Wiliams - he even sent me some DVDs, one of which was an entire paint process from a Gulfstream facility in Houston, TX. They showed how they strip, prepare, apply corrosion treatment, prime, and paint a Cessna Citation - what a process! I decided on self etching primer instead of alodine and epoxy primer after finding a post on VAF from a guy that had made a test panel with about 7 different types of primer solutions, including self etching primer. The main issue about this is if the self etching primer really acts as a good anti-corrosion barrier for the metal, with some arguing that the primer actually soaks up moisture instead of repelling it. The guy with the test panel was an employee of a paint company who took the panel to various trade shows, and then finally set it outside in the elements where it was rained and snowed on for about 8 years. The result - all of the primed solutions, including the self etching primer, had stood up well. This was the information I was looking for. So I bought a quart container of NAPA TE504 self etching primer and a gallon of the TER 514 catalyst/activator (not the same as the NAPA 7220 spray can stuff- the stuff I bought is the good expensive stuff that must be mixed and sprayed from a gun). Just to give you an idea - 1 QUART of the primer and 1 GALLON of the Activator set me back about $200.00. Not cheap for sure......
The first of the two work benches I had built unfortunately ended up with a small bow in the table top as a result of bad wood that I used for the frame. Several shims and repositioned cross braces later, the table top is now relatively level - so that problem is resolved.
It's official! October 6, 2009, I actually started on the rear spar of the horizontal stabilizer. This involved a lot of hole drilling and partial fabrication of of some thick reinforcing bars. Priming parts and riveting them together is just around the corner... Pics and more info in the next post.

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