New Builder: Am I doing something wrong here?

[ReidW]

Hi folks,

I recently got the workshop all set up, practice kits completed, and am starting to put rivets in the real thing. I spent a lot of timing getting my dimpling setup and technique just right so that the areas around the dimples have no distortion whatsoever, but I’m starting to put in the flush rivets on the VS and am a bit worried I’m doing something wrong. Prior to shooting the rivet there is no distortion but afterwards it looks like the river has pulled the skin just a bit tighter than the clecos could and the result looks like a bit of a dent/concave region around each rivet.

I’m using a mushroom set and a tungsten bucking bar, being as careful as possible to not let the mushroom set move or bounce. Pressure is set such that it takes 3-4 seconds to set each one.

I don’t have a buddy close by to compare with what it ought to look like and I haven’t seen one up close in a while so it’s likely I’m just being OCD, but thought I’d ask the experts before I get too much further. Thanks!

 

[skelrad]

I was a perfectionist too - now that I'm on the finishing kit of my 9A, I've been cured of that! It honestly doesn't look bad in the pictures. Go look at most planes on the flight line and you'll see they all have it somewhere.

In my limited experience, I've found that one cause of this is if the angle of the underlying flange isn't parallel with how the skin should set (or the flange sets lower than it should), causing the rivet to pull the skin down to meet the flange. It's not that you're pounding on the rivet funny or anything. Some parts, especially those that attach to ribs, just have a tendency to do that if the parts aren't sized/mated perfectly. Take a look at some completed wings and you'll see that a lot of them have this effect at the rib rivet lines.

 

[airguy]

I was a perfectionist too - now that I'm on the finishing kit of my 9A, I've been cured of that! It honestly doesn't look bad in the pictures. Go look at most planes on the flight line and you'll see they all have it somewhere.

In my limited experience, I've found that one cause of this is if the angle of the underlying flange isn't parallel with how the skin should set (or the flange sets lower than it should), causing the rivet to pull the skin down to meet the flange. It's not that you're pounding on the rivet funny or anything. Some parts, especially those that attach to ribs, just have a tendency to do that if the parts aren't sized/mated perfectly. Take a look at some completed wings and you'll see that a lot of them have this effect at the rib rivet lines.

That's about what they should look like - you're fine, build on.

 

[BobTurner]

Always hard to look at photos. But, imho, 4 seconds is too long. Try higher pressure.

 

[Mike S]

Reid, welcome to VAF

Agree with posts above, try upping pressure a bit, but they really do not look too bad.

 

[wirejock]

What size mushroom set?
It does look like maybe the set is leaving a dimple. Nothing wrong, but if your a perfectionist, you want to figure it out.

 

[acam37]

I transferred my RV riveting skills to building Cessna wings, stabilizers, and flight controls. I exclusively use a 4X gun and ditched my 2X and 3X. It’s all about air pressure and trigger control. Unless you back rivet it’s almost impossible to not get a small amount of distortion around the rivet heads. You will be fine as long as you don’t jack hammer the rivet.