Monday, October 08, 2007
Painting the Engine Room - Part 1
The engine has been delayed, thanks to some administrative confusion at the rebuild shop where it was sent. They have yet to start the repair, so I can't expect to be airborne again until November at the earliest. The shop has promised to expedite the process, and I won't pressure them beyond that. I'd rather have this done carefully and methodically, without rushing or cutting corners to meet an arbitrary deadline. I'm not too happy about this, but I'll manage.
And the best way to do that is to come up with another project. A couple of years ago I filled a long winter break with my first real Bachelor Kitchen project, which involved repainting the upper engine cowling. It turned out pretty decently, and I've been eyeing the bottom cowl ever since. The bottom is a more complicated process, since it involves the landing light housing and cowl flaps, and some damage to the fiberglass nosebowl adds even more work. And on top of that, repainting the exterior will mean finding a match for Cessna's Tiger Yellow and Summer Gold trim colors. I have at least a month to play with, so let's get started.
Here's what we have to work with. There's a lot more cooked oil on the bottom end then there was on the top, and despite occasional oil baths from assorted leaks, there's plenty of surface corrosion. Scrubbing this clean is going to be a chore. At least I won't have to do it in the kitchen.
There's grime all around, and lots of places for it to hide. there's even a spot where the skin has been worn down slightly by the spiral steel wire in the carburetor air duct. When the new SCAT goes in, I'll make sure that there's not enough slack to let that happen again.
Disassembly comes first. A dozen or so screws hold the landing light housing in place, and the cowl flaps come out nicely when the hinge pins are removed.
After several days of scrubbing with Alumiprep and Scotch-Brite, the aluminum looks like aluminum again. There's still a ways to go, but it's a nice feeling seeing this much improvement.
The Bachelor Bathtub is as good a place as I'll find for applying the Alodine treatment. You married guys wouldn't be able to get away with this sort of behavior.
Scotch-Brite wheels in the drill make short work of the rust and crust on the landing light brackets. They do a good job of removing skin from the shins, too. Don't ask me how I know that.
After a few more days of shin skinning work, the innards are primed.
A few coats of Engine Room White, and it's starting to look seaworthy. It will take a few more coats, but first we'll deal with some fiberglass repair.
At some time before I met her, Yellowbird's cowl snubber bracket went missing. Untold hours in the air allowed the lower cowl lip to chafe against the spinner bulkhead, wearing away most of the lip. The snubber bracket was replaced at our first annual, but the damaged lip has defied treatment until now. It took a few tries to figure out how to rebuild it. In the end, I took a length of aluminum strip, bent it to match the radius of the top cowl opening, and used it as a form over which fiberglass cloth and resin were molded.
After trimming the excess, I filled any gaps with Aeropoxy filler. It matches the original dimensions pretty well. I also used the fiberglass cloth to reinforce the area around the snubber.
This is the landing light housing. Interestingly, it's a steel stamping, instead of aluminum. I stripped it inside and out, primed and painted.
For variety, I painted the inside with the same high-temperature aluminum paint that I used on the engine baffles. This part sits right under the muffler, so it's exposed to some heat.
Painting the exterior is going to be a task. I'll have to do some body work, mask the trim stripes, paint, polish, and finally put everything back together. Stay tuned...
