Piano hinge install?

[Esser]

I guess a little time and detail go along way. I have seen RV guys mess with their hinges for 20 minutes trying to get their cowl back on. If it can be made to be fairly easy to put back on I would think about doing it as it looks so nice,

[HighWing]

James, Thinking about your question further, I don't think I answered it. As the hinge is bent, it will remain flat so yes some accommodation will be needed to correct the bedding of the hinge. Lancair folks use clecos a lot when positioning panels that are being glued together. It is messy and requires cleaning the clecos from resin residue from time to time.

The procedure is to fit the hinge in position with clecos. It will result in gaps in areas between the hinge and the cowl skins. This is the way I took care of that. A half inch drum sander in a dremel is great for trimming spots to get the hinge positioned so the outside surfaces are close to being flush with each other - don't sand the glass too thin. - After everything fits closely mark the hinge halves as to which goes where on the cowl halves. Pull the hinge pin so the positioning of the top and bottom parts are done separately. Cover the mating surface of the hinge half with clear packing tape wrapping the tape around the back side of the hinge covering both sides and trimmed to clear the hinge cuts. Mix a batch of thick Micro or feather fill, spread it in line on the cowl half where the hinge will be located. Reposition the hinge and cleco the units together. Carefully remove the excess micro to prevent it from getting in the hinge cut area. Put top and bottom cowls together and replace the pin. You may want to remove each cleco one at a time to wipe them with an acetone wipe to remove excess micro. Allow to cure.

After the clecos are removed, the parts can be separated to remove the tape separator for contour and scuff sanding. After scuff sanding the mating surfaces of the hinge and the cowl, they can be hysoled together. Use the clecos to position and follow with the rivets. I also dipped the rivets in the hysol before squeezing.

Final surface contour is accomplished by using the micro/Feather Fill and spread it on the hinge area to level both sides. This is when the knife run along the hinge will open the hinge joint enough for separation and clean up.

I hope I thought of everything this time - someone let me know if not.
Lowell

[WurlyBird]

Again, thanks HighWing. You certainly got the important points for me. I had "played" with the hinge a bit and it is possible to have a bend in the hinge while it goes around a slight curve but I did not know how difficult it would be to secure properly. Filling with micro to allow the hinge to be flat while it curves makes a lot more sense. I was out in the garage between posts and there is really not that much fill that will be needed.

[HighWing]

I guess a little time and detail go along way. I have seen RV guys mess with their hinges for 20 minutes trying to get their cowl back on. If it can be made to be fairly easy to put back on I would think about doing it as it looks so nice,

Maybe the blades on the front of my top cowl helps. The only problem I had was early when everything was very tight. It was hard to get the hinge pin started. Now it probably takes less time than it took to fit and close all the camlocs. I also don't need a screwdriver for the main cowl - but still do for the ring cowl up front.
Lowell

[WurlyBird]

So I have since installed the piano hinge on the cowl and on a whim I conducted an experiment with great results. The piano hinge will accept a compound curve.
I started at the nose on the upper cowl, which has more curvature to it, drilled and clecoed every six inches or so, moving aft and keeping the hing at the proper height from the cowl. I removed the clecoes, installed the hinge wire and re-clecoed the hinge. I again worked forward back in six inch increments securing as I went. The hardest part was working inside the cowl while trying to hold it in the right position. After the initial install I attached the hinge every 1.5 to 2". The parts are now epoxied and riveted and function perfectly.

[Esser]

Take any pictures of the install?

[WurlyBird]

I will try to get some pictures in the near future but I am sort of living in the woods on a government funded camping trip at the moment. I will forwarn you that it is not pretty though. I used blind rivets as I have not been able to find good instruction on solid rivets and have only dabbled with them. Once envy thing is done the inside of the cowl will probably be painted over to cover it up a bit.

I will try to get those up soon (thee weeks ish).