D

DJR

Active Member
Another cracked canopy (photo)

http://picasaweb.google.com/lh/photo/Tv4pvF9sibsUFUjKs0qnug?feat=directlink

I seem to have small cracks around a drilled hole in the back of my -8 slider. I think these cracks are refered to as Crazzing, but not to sure. I have attached a photo. I have tried sanding them out but they are too deep. Could anyone tell me if this is something that I should try to fix or is there nothing that I can do at this point.
I never noticed the cracks until after I used Denatured alcohol to clean tape residue off of the area. I really believe the alcohol caused this.
I have read about IPS weld on 3 cement, but I dont know how I could ever get that stuff into these cracks.

Any advice is much appreciated.

Thanks,
Dana

Well, i tried to insert a link. not sure if it will work
 
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I think WD-40 is the best stuff to remove tape glue on plexiglas. Not sure about a fix for your cracks, though. Sorry.
 
terrykohler said:
Dana:
You should never use alcohol on or near acrylic/plexiglass:
http://www.youtube.com/watch?v=cU9Ty0L0g7E
Don't know how you can fix your problem. Let's see if there are any polymer engineers or chemists out there who can help.
Terry, CFI
RV-9A N323TP
Click to expand...

Ouch, That youtube video is impressive. I once owned a single Cessna that had crazing on the front lower section of the wind screen. It never developed into any cracks and we left it out in the Texas heat for years. I know it doesn't look pretty, but it may not be a big deal structurally. Sorry....
 
Some time back there was an article in Sport Aviation on how to fix cracks in plexi. Do any of you remember what issue that was?
 
DJR said:
I have read about IPS weld on 3 cement, but I dont know how I could ever get that stuff into these cracks.
Click to expand...
Weldon-3 is very thin stuff and will wick into cracks by capillary action. You may be able to help this process by flexing the plexi around the cracks a bit.

I put a crack in my canopy while drilling it. Stop drilled and glued with Weldon-3. Five years and 550+ hours later it hasn't moved an millimeter. I live in Wisconsin and routinely fly in temps down in the low single digits in winter, with no problems. Weldon-3 is good stuff.
 
In regards to using alcohol on Plexiglas, once my canopy was painted and assembled for the first flight, I saw a lot of goop from the plastic that was covering it. It gave me a heartache thinking of how am I going to be able to clean this (it was awful looking) I surely did not want to use MEK or anything that strong but any thing mild was not making any dent in it. After consulting with a couple of friends, they said they use rubbing alcohol all the time and it won't hurt it. So I used rubbing alcohol was able to clean it with taking my time and little by little.

I have only 125+ hours on it now but no cracks or haziness at all so far.

Mehrdad
RV7A - IO360M1B
 
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