Window Gooped In

So, today I could work a day session as I was on night duty for tonight. Just as well to use some daylight to get the fuel window in. What a gooey job. I rehearsed the upcoming action for about half an hour before mixing the Pro-Seal. i wanted to be sure I had a feasible plan of action and ready to go when the clock started ticking for the pot life. I am glad I mixed a little more Pro-Seal than I thought that little area would need. I mixed 30 grams and I used it all up.
Yesterday night I did the deburring and scuffed up the flanges of the backplate and also the parts of the window that are critical for being leak-proof. That is the plastic where it would touch the aluminum around the large holes in the skin allowing to judge the fuel level and the area around the cutouts in the window where the screws hold the nuts on the plastic. I used a 1" SB deburring wheel on a die grinder until the plastic wasn't shiny anymore. My hope here is that this will allow the Pro-Seal to stick better to the surfaces and provide a better seal against leaking fuel.


The inside of the tank skin I had already scuffed good with a maroon SB pad a few days ago.
After all this prep work was done and the parts where thoroughly cleaned with isopropylic alcohol (that stuff is OK with the window plastic), it was time mix the Pro-Seal. I filled almost all of it in the syringe as usual.
The toothpick part I didn't do. I used a small spatula that Mickey D is giving away as coffee stirrers to apply a thin coat on the outside of the tank skin where those two initial screws are being put in to allow for holding the window and adjusting the backplate.
The holes for the screws in the tank skin are tight and I decided to leave them as is and drive the screws through with an electric screwdriver. My hope is that this tightness will help seal these holes. After the screws were in I started the sealing job. I laid a string of sealant from the syringe around the window holes, staying just inside the screw holes. Then I laid a second string around the window holes just outside of the screw holes. Then I put the window in and let it just sit on these strings.
Next was to squirt some sealant in those window cutout that allow for the screws to penetrate it. I filled all these cutouts with sealant before laying a string on the flanges of the backplate (this step was probably not necessary). I carefully put the backplate, making sure that the screws were coming through the correct holes in the backplate before letting it touch the plastic of the window. This worked out fine.
Then I put all the missing screws in there. I started them without putting sealant around the hole or under the head of the screw. Just drive them into the hole and leave them out about 1/8". Just enough to get some sealant pressed under the head with the syringe. Then use a manual driver and slowly screw it in until the head touches the skin. No problem here.
So far so good. Now it was getting messy. Those washers had to be put in place and therefore they had to get some sealant. I chose to not put the sealant on the washer and then put it on (I tried that twice, gross). I chose to squirt some sealant around the penetrating screw on the window and then set the washer into that turd of sealant. Your glove is going to get severely covered in sealant and you might have to change it frequently to maintain a grip on these little parts.
Next were the hex nuts. No escape here! I had to take every nut and squirt some sealant on them before starting them carefully on the threads if the screw. I think I had to change my glove about 3 times for the 22 nuts.
Then the nuts had to get tightened which I did with a 5/16" socket and a screwdriver. I held the screwdriver and used the socket to get the nut tightened. Just as Van's noted, I just set them finger tight. Why this is so important I'd love to understand but at this time it escapes me.
Finally I had a tiny bit of sealant left in the syringe and so I decided to clean the installation up. I put a nice seam around the window filling the ledge to the tank skin and then I put some sealant on top of the hex nuts where the screw penetrates.


And that was that. Now it's curing and it will take at least a week before I want to really test this with water and soap.
By the way, I had a little bit of sealant pressing through the window holes but not too much and I think once it's cured it will be easy to get it out and it might not even be visible after that.
The whole job took me two full hours, including planning the strategy.