What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Strange crack in skin. Why would this happen?

543TB

Well Known Member
Okay, friends. We've been building for awhile, and completed the leading edge (outboard) section on the left wing back in November. While out in the garage this week, we noticed what appears to be a crack in the skin, top-side, right along the rivet line where the bracket for the stall warning assembly lies. As you can see, however, the crack does not extend to the rivet hole. Why on earth would this occur, and what can be done about it? (We are sending Van's the same question, but wondering what the collective knowledge of the Van's-verse would say.)

e58bd124-a8fd-4567-87b3-40961998bf1e_zps8026bc0e.jpg


IMAG0603_zps78e3bcb1.jpg
 
Is this a crack or is it something that has been smashed onto the skin during riveting?
 
Is this a crack or is it something that has been smashed onto the skin during riveting?

It appears to be a small stress crack, but the weird thing is that it didn't show up until recently. It was definitely not there when and right after we installed the stall warning kit, and it isn't raised, which would indicate something between the skin and bracket. The wing has been on the stand the whole winter, and there is no damage around it, so it doesn't appear to have had something hit it. I'm mystified by it.
 
Is it truly a crack?

Could it have been a sliver of something hard getting in the way during dimpling or riveting?
 
Get all that plastic off. If you have been building for a while it may already be a nightmare to remove.

And you can get corrosion growing under it. You are not doing yourself any favours, trust me.
 
Get all that plastic off. If you have been building for a while it may already be a nightmare to remove.

And you can get corrosion growing under it. You are not doing yourself any favours, trust me.
+1 with this statement! It is hard to tell what the dis coloring is on the plastic but leaving the plastic on the metal for any length of time is not good at all.
 
Not a crack

I doubt it is a crack. A crack can only be formed by repetative or extreme bending of the metal. Since this is a new assembly that has not seen either of these it is most likely a scratch or coining from debris when riveting. You can burnish most of this out if you want to with a scotch bright pad. I would not worrie about it though. Work towards good quality not perfect quality. The latter will never result in a finished airplane.
 
There may be a "drill shaving" contaminate under the skin that is sandwiched under the skin, between skin and rib.
 
Do you have kids/wife ? Never underestimate their ability to damage something in a way you could not ever imagine - and then deny it no matter how much supporting evidence you have. Most of the time they don?t even realize or remember what the did.
 
There may be a "drill shaving" contaminate under the skin that is sandwiched under the skin, between skin and rib.

+1 for this opinion. The stress riser appears to be pushed outward which would seem to indicate there is something between the skin and the rib stressing the metal. Regardless, you need to check it out. :(
 
The dimples seem a bit oversized too, but maybe that's the camera angle.

Where in Denver is your project? I'm sure I or someone else would be happy to stop by and check things out in person.
 
Denver Builders

Andrew,
Give me a call if you want to plug in to a great group of builders in the denver area.
Bob Markert
303 882-7410
 
Back
Top