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Washer Backing for Blind Rivets in Fiberglass?

rockitdoc

Well Known Member
Sponsor
Van's doesn't say to do this, but I wonder if it would be a good idea. It seems like the pulled end of the rivet needs something more solid to bear against, especially when the glass is countersunk. Thoughts?
 
Depends on how strong the f/g needs to be to support what is attached with the rivet. I have used them in several areas. Vans even calls for an backing strip when rivetting on the cabin top on a 10.

Larry
 
Depends on how strong the f/g needs to be to support what is attached with the rivet. I have used them in several areas. Vans even calls for an backing strip when rivetting on the cabin top on a 10.

Like you said.... it depends on the situation.

The RV-10 cabin top is a structural member of the fuselage so a backing doubler strip is specified.
For small fairings, etc., no doubler works fine.
 
Rivets in fiberglass

After a few flight hrs many RVs will exhibit paint cracking around rivets that are set in fiberglass. In these situations I like to install rivets with some adhesive. G-flex, pro seal or Hysol all work well.

Don Broussard
RV9 Rebuild in Progress
57 Pacer
 
This is what I did

Seemed easy enough to put some #4 washers for the rivets to bear on sandwiching the fiberglas between.

Might not be needed for fairing tips and such, but why not add a little reinforcement?

I know....extra weight! :D
 

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Backing strip

Use a backing strip and when you apply the piece also bond with epoxy and micro balloons. This will help lock the rivets down and minimize the chances of the rivets wearing the glass.
 
Use a backing strip and when you apply the piece also bond with epoxy and micro balloons. This will help lock the rivets down and minimize the chances of the rivets wearing the glass.

Yeah. I used some G Flex to hold the washers in place. But, next time (rudder fairing) I'm going with Wirejock's strip method. It will spread the load even better than washers.
 
Wouldn't it be beneficial to do a washer on both sides for the rivet to hold to? seems like fixing only one side would allow for it to happen to the other?
 
Wouldn't it be beneficial to do a washer on both sides for the rivet to hold to? seems like fixing only one side would allow for it to happen to the other?

The recessed rivet head will spread the load some, the pull side has a smaller area to spread the load. Also, then you'd have to blend the washer on the top side somehow.
 
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