Saturday, April 21, 2012

Canopy Removed

After looking at the cured epoxy this morning I decided that it looked pretty good.

I was planning for one more application of dyed epoxy and then call it quits. So I started wet sanding with 220 grit and dulled the surface.

These looked so good that I decided at this point to call it quits and to focus on the lower tape line towards the sheet metal skirt. This was worrying me for a while as I had to hold the sander overhead to come nicely down to the tape line. This time I decided to just use the edge of the sander and to cut through to the tape. That worked pretty well. And I could finally pull the upper and lower tape line and wet sand the edge into the metal skirt.

Next step was locating and cutting open the bolt holes. On the right side the bolt and the dollop of wax was still showing through the epoxy layup at one spot. Using this as a reference I did some measurements of this position in respect to the firewall skin edge and the firewall shelf and I copied that over to the left side. I also used the trim template to verify that this position was not completely off and then I drilled, successfully.
I used the Dremel tool to open up the holes, large enough to get a nut over the bolts.

And then I removed the tarp for the first time in weeks, getting ready to separate the epoxy from the protective tape on the fuselage.

I was using a "knife" for forming the icing on a cake which is nothing but a thin dull blade of metal. This worked pretty well until I got to the center section of the canopy.

The skirt seem to stick to the tape there and instead of separating the two, I seem to be ripping through the duct tape. Not good! I relieved the other side of the canopy in the hope I could just push it up.

To no avail, the skirt was tightly connected to the tape it seemed and I had to ignore the threat of scuffing and scratching the sheet metal it was formed to and just keep on cutting it loose.

Finally, with the help of my wife and repeated pushing and shoving we got it loose. We tried to open the canopy but the layup started bending dangerously when close to the full up position and so we decided to just tip it up enough to get to both bolts on each side and remove in this position. It worked out ok and we could finally lift the canopy off the fuselage.
Removing all the gunk from the duct tape that got stuck on the fuselage when pulling it off, took quite some time and I needed almost a quart of acetone to wash it off.

I cleaned up the underside of the skirt, removed the duct tape from the front bow and also peeled out the insulation material I had put in the gap between canopy glass and fuselage aluminum to avoid epoxy running onto the panel. And then I saw what must have happened. Somehow, and I really don't understand how, there seem to not have been any mylar tape over the center section. I am sure I put it on but clearly, it's not there now. The epoxy had a long time to seep into the duct tape and tightly bond to it. Fortunately, I had put two layers on, so the the upper layer bonded to the epoxy while the lower layer still protected the aluminum. I'm not sure what to do with this. I won't be able to get it off without messing up the skirt, so I will leave it on and have to find a way how to stop the stickiness. Prime it? Put a coat of epoxy over it? I'm open to suggestions!

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