[msturgis]

So im rather unhappy with the way my right elevator's leading edge turned out.

There is a small gap where the skins should be laying flat against each other. I added extra rivets to help combat the "pillowing".

I know this area is hidden by the HS. However do I need to start over? Try and drill the rivets out? Like I said I added an extra rivet between each predrilled hole.

 

[Stevea]

Hard to tell from the photo exactly what the problem is, but a couple of things come to mind.

1. Put a slight edge crease on the outside skin of the overlap. (tools from Avery, Spruce, and others to do this.)

2. Make sure the rivet does not swell between the skin layers. (looks like this might have happened) Push the pop rivet tool hard enough to fully seat the rivet and slightly deflect the skin joint, then pull the rivet.


If either of these caused the problem, you can drill out the rivets, crease the top skin edge (if required) and do them again

 

[Chino Tom]

It is at the leading edge. It will be inside the HS skin. No one will ever know
but you.

 

[msturgis]

I did put a crease in the top skin.

I am willing to drill the rivets out and replace if this gap is structurally unsafe. However I am a little nervous about drilling out pop rivets and making the matter worse.

 

[[email protected]]

if you choose to drill the edge out...

there are a couple of techniques to use that can help if you choose to drill everything out...

as stated using an edge roller to give a slight break will help... since these holes are not countersunk you can still address it if you drill everything out.

even more effective here is to ensure that the top skin is rolled over more tightly than the bottom one... to do this you need to bend roll it quite aggressively and then pry lever it back on top; the extra pre-load in the bend will help it to clamp down on the bottom roll layer more tightly... just make sure that you concentrate the rolling towards the edge since you have a good general shape.

also as stated it appears that you have a bit of a gap between skins at the rivets that is likely from light pressure when pulling... i apply firm and steady pressure for the first pull and relieve the pressure to neutral or even slightly negative just as the rivet mandrel is ready to break.

 

[Shockwave]

I had beginner's luck on my rudder and it's been downhill from there.

I drilled a couple out, and found it wasn't any harder than drilling out any other rivet despite the warnings. One edge ended up a bit over-curled, so I stuck a wooden dowel down the inside and forced the inside skin out while I riveted it. I kept clecos in every hole and cleco clamps on the ends.

Personally I'd be tempted to drill out the 3rd rivet and see if you get it to sit better. It looks like the head isn't quite flush either. On the other hand, it is purely cosmetic and mostly hidden at that.

 

[msturgis]

So when drilling out a pop rivet, does the head come off like a solid?

 

[Shockwave]

So when drilling out a pop rivet, does the head come off like a solid?

I did it just last spring and I don't remember for certain.

I'm pretty sure I drilled the entire rivet out. First, it was somewhere past the first couple of rivets so I had no access to grab the shop head. Second, I remember having a bunch of aluminum spiral wrapped around my drill bit.

 

[David Clifford]

I had similiar problems with mine though not as severe. I tried drilling out the first few but if the rivets spun, the holes would enlarge. I ended up using my Dremel and very carefully grinding off the heads flush or almost flush, and then punching the rivet out. I re-rolled tighter and bent the edge down for a tight fit. Clecoed every hole and re-riveted one at a time paying more attention to a good tight fit as I went along. Since a few of the holes were now oversize from the rivets spinning, I drilled a new hole centered between each plans rivet and put a rivet in those. The rolls and fit were now much better and with the added rivets, I felt good about its structural integrity. From then on, I am real carefull about fit before the rivet is set.

 

[mcencula]

Getting the right curvature

...is really hard. I found the best technique is to try to get the curvature right near the spar, but without getting a crease at the spar. My technique was to get the curl started, then "pull" the edge towards you using your hands to guide where the curvature is set. Here's a picture of my friend, Dan, using this technique:

Most of the force is applied in pulling. Not nearly as much in curling with your fingers.

When done, the rivets won't be under hardly any preload.

Hope that helps and good luck.

 

[Phil]

Hey Matt,

Bring that thing over to my house and we'll work on it.

Phil

 

[chunt0]

Matt, if you do drill out the pulled rivets, don't forget to drive out the steel mandrels first. Like many other things, you may want to make up a sample piece to practice on. Done right, it really is easy.