Inside Cowl

Time: 4 Hours

I started the process of sealing up the inside of the engine cowl. You do this for a couple reasons. First is to keep oil and other fluids from soaking into the cowl and the honey comb interior. The other is so it can be painted, although this isn’t required, as it will help down the road to identify any leaks. Most paint theirs with a light color like white to make the leaks easier to see. Another reason to smooth the lower cowl inside is so that the adhesive backed aluminum heat shield material will adhere better. So to start this long process I worked on the tube that will direct the hidden oil door retention pin. Ok so that may be confusing. So let me explain, I’m using the hidden hinge from Cleaveland Tool on my oil door. This makes a nice clean look without and visible hinge. To latch the door down you can do many different things but I decided to use hinge and it’s pin to secure the door. When the pin is in place the door is secure and cannot accidentally open if the door flex’s under pressure. So how to pull the pin when the cowl is in place and the door is secured. I decided to make the pin extra long and access it from the inside of the baggage compartment. The idea will be to open the baggage door, pull the pin just enough for the door to open. To close the door I would hold the door flush and push the pin into the hinge. But trying to aim the pin several inches to the first hinge eyelet with seeing it would be very difficult. So I decided to secure a aluminum guide tube to the inside of the cowl. I fluted the opening a little so that the short distance the pin will have to go and the flute helping direct the pin into the opening will make it easy. I used the pin to keep the tube aligned and some washers for the correct height. I then laid up two layers of fiberglass over the top of the tube and let that cure to give it a secure hold. After that I used Super Fill to give it a good shape and sanded it to look nice. I’ll work on the pin later but for this part it looks good and hopefully works ok. I then filled and sanded any big imperfections in the cowl surface before sealing it. The process of sealing for me is just using epoxy without any fillers and thinning it slightly with acetone. Then I brushed it on the entire surface with a cheap brush. Then with a old hotel key, the credit card looking ones, I scraped all the extra epoxy off. This forced the epoxy into all the tiny pin holes and voids. Then after that cured I did a light sanding with my maroon 3M pads to knock down the high spots. I cleaned up the entire surface again and repeated the process. I think I will repeat the process one more time then primer and paint. For now I’m thinking an aluminum color high heat engine paint but not sure yet. While this one cures I started the filling process on the lower cowl. I gave it a good sanding to get rid of a bunch of imperfections from the manufacturing process. I’m going to spend more time on the lower cowl as it will be seen more especially if I have it judged at AirVenture some day. When people are looking at the engine the lower cowl is really visible. I will keep working on it but for now I need to get all this dust off me.

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