I've been holding off on writing this blog until I finished up the task. Well, it took A LOT longer than what it was supposed to.
Dates and Times
Wed 30 -1.5hrs- finished light wiring
Sat 3 -5.5hrs- window edging prep
Sun 4 -5.5hrs- window edging laid up
Mon 5 -1.5hrs- window sanding and disaster
Tues6 -1.0hr- sanding off old stuff
Wed 7 -1.25hrs- more sanding
Sat 10 -6.5hrs- window prep and laid up new layer of fiberglass
Sun 11 -3.0hrs- more sanding
Tues13 -0.5hr- more sanding
Sat 17 -2.5hrs- so much sanding
Sun 18 -3.0hrs- more sanding and cleaned out the shop
I started off masking and sanding all of the windows. I used the same tape as I did for the windscreen fairing.
A closer shot of everything taped off. I used the same little jig tool to draw a line around the window offset from the edge to place the tape. The radius's at each corner are from circles I printed off on paper of many different sizes. I then cut out the radius I wanted which made a good template for the curve.
Here is a shot of the edge of the door. You can see how I placed tape around the entire perimeter of the door, two layers of duct tape and a layer of electrical tape. I then cut it even with the outer skin of the door. This will result in an even gap around the entire door. You can also see in this picture how the door has a nice sloping curve and the cabin top does not resulting in a slight misalignment.
I then taped around the edge of the door and onto the outer skin to prevent fiberglass adhering to the door itself. In this image you can also see a flat spot on the cabin top in relation to the door....its right in the middle of the picture.
With everything taped up I laid my first bit of fiberglass. First I filled the gaps around the edges of the windows and then laid 2" fiberglass cloth down. The strips were cut from the same type cloth used in the windscreen. I only did around the top of the windscreen and the back windows at this point.
The next day I came out to start sanding everything down when I discovered that nothing was sticking. The glass cloth was peeling off in strips....not good.
This resulted in days of sanding and scraping to get all the old stuff off the plane. It was a major pain in the butt and very disappointing. This set me back a few weeks of work.
I think I know what happened:
1. Original: sanded with orbital sander and 60 grit paper. The orbital didn't "scratch" up the surface enough. New Layup: used 60 grit paper and sanded in 90 degree patterns creating a "scratched" cross pattern around the entire perimeter.
2. Original: cleaned with acetone and therefore smoothed out the ridges from sanding.
New Layup: cleaned with just water.
3. Original: Laid cloth down and applied a thickened epoxy. I was thinking of preventing runs but resulted in cloth not absorbing enough of the resin to harden and adhere properly.
New Layup: wetted entire perimeter with just epoxy and then did a very wet layup of the fiberglass using non thickened epoxy.
The second time I did this the layup looked much nicer than the first. Practice is everything.
This time I also picked up a flexible sanding block and adhesive backed paper. The sanding block is very important to getting a nice gentle curve. VERY important...basically not possible without it.
The second layup stood up to the sanding and trying to peel it off. So with my new sanding block I started sanding, sanding, and sanding. Here is a picture of the old intersection I showed above. Looks much nicer now.
An overall picture. So much sanding. I am not really enjoying this part. Fiberglass dust is awfull stuff.
I finally got a point that I can say I am finished for now. The dust was so bad in the shop dunes were starting to form. I just pulled everything out and blew it off with the air hose. My next goal is to finish a few things up in the tail so I can rivet that last skin on. Then I will finish the rest of the body work for good.