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fiberglass over windows

S

stamper

Well Known Member
just a quick question. How many layers of the light oz fiberglass did you guys put on over the edges of the windows to finish them out. Was going to order some 1..5 oz for this part. Any advice?
 
Me too

I put a couple of 3-5 oz layers if I recall, but then sanded a lot of it off in finishing. Mine are starting to crack slightly in a few places. If I did it again, and I may eventually try to repair them if they get bad, I would use a 1" fiberglass tape with finished edges, like this:

http://www.ebay.com/itm/like/271531420866?lpid=82

I would overlap 2-3 layers and then fill to the fiberglass, feathering away from the window, instead of sanding down the fiberglass to be level with the surrounding cabin top. Be sure to scratch the plexi that the tape will adhere to VERY well, maybe 36 grit, to make sure it has tooth. Once you have the tape spanning the joint, don't sand into it any more than you must.
 
I put two layers on. I don't remember the weight of the cloth, but it wasn't light weight. It was the same cloth I had on hand from the various tips.

It's coming up on a little over two years now with no cracking.
 
I used two layers, but there would be overlaps of 3 or 4 layers in the corners... where people tend to have cracking.
 
window fiberglass

Thanks for the response, I was going to do some little cloth but after seeing your threads it looks like the heavier oz stuff may be better. I often wonder if the cracking is do to the lord adhesive that people are using to install their windows. There is no give with the expansion of the windows do to the heating and cooling of the plexiglass.
 
top cowl question

Hey another question. Was going to work on my cowling tonight and it says to use a plumb bob to level the top cowl. Can a guy just measure from the floor to the cowl and get the same effect?
 
stamper said:
Thanks for the response, I was going to do some little cloth but after seeing your threads it looks like the heavier oz stuff may be better. I often wonder if the cracking is do to the lord adhesive that people are using to install their windows. There is no give with the expansion of the windows do to the heating and cooling of the plexiglass.
Click to expand...

No, I think the lord adhesive prevents the cracking. I used Lord adhesive and have no cracking.

Most of the people I know that have cracking, used Weldon.
 
I used 3 or 4 layers of the fiberglass tape from Aircraft Spruce - 2" E-glass, I think. Weldon for the windows (never again!). No cracks so far.

John
 
I've always wondered - if fiberglass is used to bridge the gap between two materials that, at least per conventional wisdom, expand and contract at different rates, then shouldn't cracks be expected in the rigid connection? I'm considering filling the crack but not using FG for a 'cover,' but expecting to eventually see a crack or two anyway...

==dave==
 
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