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Glassing Window Seams

AviatorJ

Well Known Member
Today I went out and installed the windows into the doors as well as the rear windows and the windshield (Minus all the glass work).

I used Lord Adhesive and it all turned out fairly well. There only 1 spot on the rear left window that is about 1/16th higher than the cabin top. I'll sand that edge to blend it before glassing the seams. Which then occurred to me I may or may not know what I'm doing when it comes to that.

Next to glass in the seams is it just a single layer of about 1" wide fiberglass around the entire perimeter? I have 3/4" of the edge of the windows taped out and roughed up so that would leave an over hang over around 1/4" that I would blend into the cabin top.

After the seams tape is cured would I then just plan on micro'ing everything as I finish up the cabin top exterior?

Thanks in advance!
 
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After the seams tape is cured would I then just plan on micro'ing everything as I finish up the cabin top exterior?

That is what I did and it all turned out very nicely and still looks great 4 years
and over 400hrs of flying.

I used a fairly thick electrical tape "6mil" to elevate the masking perimeter just a bit to accommodate the micro and achieve a consistent seam height around the windows. Using this method will allow you to sand even with the tape and make your job easier.
 
That's a good idea. I have some striping tape down now but will put some electrical over it, something bright like orange so I can see it.
 
Justin, lots of info on this. I remember seeing other threads with some pictures as well. Search around, I think most folks are doing it that way. My plan as well.
 
That's a good idea. I have some striping tape down now but will put some electrical over it, something bright like orange so I can see it.

Just make sure you use some good tape, not the cheap big box tape. You don't want any epoxy weeping under the tape.
 
I used flox with milled fiber glass on to fill the gaps where the Lord Adhesive didn't completely cover. That seemed to work well.

Next I did a layup using straight epoxy (dyed black) and this 1" fiber glass tape stuff I got from ACS. The tape is thicker than my fiberglass cloth but wanted to give it a shot. I did both rear windows, the door windows and around the top part of the windscreen. My method of laying it was to wipe some epoxy on the area, lay the tape on it and then blot the tape till it looked soaked through. Now after I got done I QA'd my work and thought the first window I did looked a bit light on the epoxy. I decided to leave it just to see. Sure enough the next day the tape just peeled off. I resanded it, layed the epoxy down thicker (Not thickened, just more of it) and put the fiber tape on it, covered with peel ply and let that dry a few days. Was fine after that.

Okay so after doing an initial sanding there were a few areas where I apparently didn't use enough expoxy like above and small pieces came off, or I had sanded it all the way through to the plexi. Instead of just covering with Micro and hoping it doesn't peel off I'm going to do another layup. This time I'm going to use the cloth, cut into pieces and do a single layer around the entire perimeter and then a double layer on the corners. This in effect will have a total of 2 layups, around the perimeter and 3 on the corners.

Now here's my question. I'm assuming I'll feather the inside edge where the windows are to have somewhat of a bevel. Maybe a 1/16th of a edge showing. Then on the outside edge feather that just to clean it up and then do micro over everything to ensure it's uniform. The end result will be a slight ridge around all the windows, does that sound right? I ask because I originally though it would be flush with the cabin top but doesn't seem like that would work, end up with too thin of material over the windows edges.
 
That is what I did and it all turned out very nicely and still looks great 4 years
and over 400hrs of flying.

I used a fairly thick electrical tape "6mil" to elevate the masking perimeter just a bit to accommodate the micro and achieve a consistent seam height around the windows. Using this method will allow you to sand even with the tape and make your job easier.

I did this as well. I would also add that you should use two different color tapes. This will help you know if you accidentally sand through the first layer of tape.
 
Talk about escalation of commitment... I went out there to work on one of the rear windows, ended up doing both of them and had some epoxy left over so started the Windscreen faring. 2.5 hours later I ended up with this...



That was a lot easier than I thought it would be. Last night set up my workstation to accommodate fiberglass cloth strip cutting so it was just a matter of going through the steps. Also at this point I realize it doesn't have to be precise so it was a bit stress free. Messy though, went through I think 6 pairs of gloves.
 
Laying up the fiberglass is the easy part. Filling, sanding to shape, and finishing is the PITA. ;-)

Yah but that's all old hat to me after the cabin interior. I'm going to wait till I have the door hardware installed and can shut the doors to start the filling and whatnot.
 
For the people glassing in the rear windows, do you recall what cloth you used? Weight etc? I see a few options at aircraft spruce and not sure if I should use the same as the windshield or something lighter?

Thanks
E
 
I used the lightest weight I could find in order to eliminate a hump and create a better transition but still cover the seam. Don't recall the weight.
 
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