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Canopy cracking when pulling rivets

skyyking

Active Member
Folks, I am worried when I go to pull the AACQ-4-4 rivets on the canopy frame it will crack the canopy. As you are aware, you can't control the pressure. I need to ask therefore; if any of you out there have had any problems, especially on the forward portion of the canopy frame where the rivet makes direct contact with the plexi.

Thanks!
 
clean everything, deep breath, HOT plexy canopy, slightly deburr holes, run slowly, everythings will go !

Warm the canopy !!!!

2c
 
I hear that the rivets crack the canopy when:
  • You don't use the correct rivets (which are particularly "soft")
  • They are "old" (=hardened)
When we did ours, had no issue, avoiding above. Of course, you will have plenty of spare plexi and AL, so do some practice with some spare riverts if you are not confident ;)

As Luke says, "slightly deburr" holes. We went one further and used fine sandpaper to polish the holes such that the "countersink" corners were all smooth...
 
I just did all those on my RV-8 canopy. OAT about 90 degrees. No problem and after I did a few I could anticipate when the rivet would pull and held the puller accordingly.
 
Like Andy says. You will find that the recommended rivets require very little pull pressure. It therefore puts little pressure on the plexi.
 
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WHY does it crack?

The times I've pop-rivetted plexi, a crack occurred when the rivet flared in the hole, not from the actual pulling together of the plexi to the support.
that said, be sure they are in TIGHT contact, and if you have used a washer or shim of any kind, ensure the rivet length is correct so it flares in the tube, not in the washer, or you get a false 'pull', and it may come out later.

all the comments on the warm or hot plexi, deburring and fresh rivets I'm sure are valid....remove any stress points.
I'd be concerned if the canopy were 5 or 10 years old also, as it hardens with age, or if stored in light or at hi temps, the moisture and/or plastic resins leach out in some way. ( IMO)
 
I also did the sandpaper polish after countersinking the holes. I also wet set all of the rivets with proseal before pulling them. All work was done in 90+ temps, so hopefully the future cracking potential is low.
 
As others have said, first make sure you use the correct rivets.
They should be aluminum!
Use a hand puller, NOT a pneumatic puller. That way you CAN more easily control the pressure.
I've done many and have never had a problem.
 
I know this is not about rivets, but I used no rivets in my canopy...everything is #6 screws, no cracks.

Jim Bower
St. Louis
RV-6A (flying)
 
Could go rivetless....

And glue it! No holes to drill, no rivets to pull.
Plenty on the forums about this!
 
Sikaflex...or not. I realize this is not the thread to discuss screws/rivets vs. glue in attaching the canopy. But I choose Vans instructions (screws/rivets) because:

  • I've wasted lots of time in the past every time I deviated from Vans
  • Thousands of RVs are flying with holes drilled in their canopies
  • The drilling can take place at leisure...the Sikaflex bonding has to happen under time pressure
  • And finally, if my canopy does crack at some time in the future, I can unscrew it and fit a new piece of plastic, keeping the frame that took me weeks to construct and fit. With Sikalfex I'd have to throw out the frame too.
 
Rivets

As stated, I used SikaFlex and avoided any hint of cracking.
Easy to use (as directed) and a very secure and nice looking bond.

Jim Frisbie
RV-9A
N571DF 275 hrs.
 
Helpful pop rivet tool

Here is one way to distribute the pressure on the plexi when pop riveting:
Cut a 1/2" x3" piece of .063 aluminum and make a shallow bend about 3/4" from the end. Drill a hole at the end with the bend just large enough for the pop rivet mandrel to pass through. Pull the rivet through this hole. This provides a much broader area of contact than the rivet puller head.

6
Another benefit of this method is that the top of the pop rivet is much flatter after being set.

I hope this is helpful.

Ken Harrill
RV-6


6
2crvx46.jpg
 
Screws

I used #6 stainless screws. Tapping the holes was a very easy. I stripped a couple but then filled those with JB Weld and re-tapped. Came out perfect.

Bevan
 
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