Saturday, October 25, 2014

Priming the Vertical Stabilizer and Rudder - 4 hours


I started priming the Vertical Stabilizer and Rudder today. After a bunch of reading on the forums, my priming tests and a quick discussion at the recent EAA meeting I had decided on a non alodine treatment. I figured just a straight 2 part epoxy primer would suffice. I do not live in a maritime environment so I figure that the maximum protection alodine would provide would be overkill for my needs. I settled on a good surface prep and then a 2 part epoxy primer. This morning I decided that I wanted to get a bunch of priming done on my parts before I go away next week. I picked up two big 50 gal containers from Lowes. I would use these to wash my parts.

Here is the priming process;

1. Parts are deburred and checked. Parts are gone through with a light scrubbing with scotchbrite red.

From this point on, all parts are handled with gloves on.

2. Just a few parts are washed thoroughly with water and Dawn detergent.
3. Those few parts are rinsed and scuffed with red scotchbrite in the water (gray scotchbrite for skins)
4. Parts are then dried with air and a clean microfibre cloth.
5. Everything is wiped down with Pro-Form wax and degreaser.
6. Everything is then wiped down with MEK.
7. Parts are primed with spray cans of Spray Max 2K primer
8. Repeat step 2 thru 7 for the next few parts.

I chose this process as it allowed the parts to be thoroughly cleaned and minimized the exposure of the newly scuffed layer of aluminum to oxygen before the primer is applied. It is fairly tedious, however with some good music playing time flys by and I can take comfort that I am at least getting the best surface prep that I think I am capable of.

The ugly side of the priming is that I do notice the increased weight of the 2K primer (Darn!!). I am giving the skins a light coat with the emphasis being applied to areas of mating surfaces so hopefully I mitigate weight as much as I can with the primer. The benefit of the 2K primer is that it is extremely tough so it will offer a level of protection when I get into riveting.

At the end of the day, I know I will be penalized for weight on the priming....however I intend to shave some weight in other areas (i.e. VFR Glass EFIS instrumentation, LED lighting, Beringer brakes and wheels, Fixed pitch propeller, etc) so hopefully things will balance out in the end.

As a side note....Its taken just over 2 full cans of primer to do the Rudder skins and the VS assembly. There's not much in a can. Ouch...that's an expensive method of priming. I estimate that it will take another 3 or 4 cans to complete the empennage. Also....it oversprays like crazy. Gets cloudy quickly in the garage when I spray!