Wednesday, February 19, 2020


With the majority of the door work done I've moved on to installing windows.  I'm using the Silpruf method that is documented in great detail on YouTube by Zach Chase.  In this series of video's he demonstrates installing a top window in a Glastar Sportsman.  It runs a bit long but Zach does a great job of going through the entire process.

One item of note about the doors...  I finally got everything back together and found that the pilot door was slightly proud of the cabin top.  Odd, I was quite certain that it was level when I took the doors off for painting.  After a few minutes of scratching my head I realized that I had done all the leveling work without the struts installed.  Those struts put a lot of pressure on the inside of the door which is causing it to flex a little bit.  That means more work leveling this area again but fortunately its not a large area.

Window opening is sanded and small standoff's made of cured Silpruf are glued to the flange with black RTV.  These standoffs were then trimmed by hand with a razor blade to the exact height needed to hold the window off of the flange but remain flush with the cabin exterior surface.

Outside of window is taped and then back cut so that it covers only the top side of the window.

Inside of window is taped with three layers of tape.  First the inner blue tape to act as a nice buffer, the second 1/4" tape that comes up close to the line that marks the flange edge as marked from the inside of the airplane with the window in place.  Then a final layer of 1/4" tape that covers the first layer of 1/4" tape but stands about 1/16" closer to the enge.

You can see all three layers of tape in this close up picture.  You can also see where I lightly sanded the surface of the window that will have the Silpruf layer.

Outer edge with tape and paper protecting the fiberglass around the window.  Paint will not stick to anything that Silpruf touches.  I will admit that I needed more tape on the top side. I thought that would be enough but I found that during the install and clean up phase my gloved hand touched the unprotected fiberglass a time or two.  Fortunately my gloves were clean.

First layer of Silpruf applied.  This is just a thin layer to give a consistent look when viewed from the outside.  It also helps hide the standoffs which can show up in the final product if this layer is not applied.

Window installed, edges cleaned out of excess squeeze out, outer tape layer removed, and inner layer of 1/4" tape removed.  it has to sit like this for at least two days...maybe more because its a little cool in the garage.

Inside view of the window.  You can see where I peeled the last layer of 1/4" tape off.  This leaves a nice clean line of adhesive around the perimeter of the window.