Wing spar corrosion?

[jcoloccia]

So I took a real hard look at those beautiful, gold anodized RV-7 spars this morning and noticed something that made me scratch my head. In one section of the spar web, there are all these teeny-tiny little pits. At first I thought it was just some really fine dust but I can't remove it by rubbing with my nail.

I've heard that corrosion can start out as tiny pits like this, but I've never seen it first hand and don't know what to make of it. I find it hard to believe that I would have any corrosion at all given that the spars are less than a year old, they're annodized, and they've spent their whole life sitting in dessert weather.

On the other hand, I don't know what else it could be. Has anyone had a similar experience on their spars? I'm going to try to get my tech counselor over to look at it this morning but I'm curious if others have found anything similar and maybe can shed some light on this.

Here's a picture. Quality isn't great but it's the best I could do.

[LifeofReiley]

By the picture it looks as is something (a chemical possibly) got splattered on the spar. Any recollection of something like this happening?

[jcoloccia]

Originally Posted by LifeofReiley

By the picture it looks as is something (a chemical possibly) got splattered on the spar. Any recollection of something like this happening?

Nope. It went from sitting in plastic in the spar box to leaning up against a wall outside our bedroom.

[LifeofReiley]

I really don't think you're dealing with corrosion here. Something must have splattered on it at the factory where the spar was built. Hit the area lightly with a scotch brite disc and spray a little self etching primer on the area. You'll be okay. I have touched up a few areas on my spars as the wings went together. You're going to be touching up countersinks on the spar with primer too.

[jcoloccia]

Here's the response I got from Vans:

We see this occasionally on some of the spars when they come back
from Phlogiston (spar assemblers).
Structurally not a problem. Haven't heard reports from the field
that it worsens. Wouldn't hurt to clean it up and prime the area,
however.


So there ya' go...prime it and move on

[Captain Avgas]

Originally Posted by jcoloccia

Here's the response I got from Vans:

We see this occasionally on some of the spars when they come back
from Phlogiston (spar assemblers).
Structurally not a problem. Haven't heard reports from the field
that it worsens. Wouldn't hurt to clean it up and prime the area,
however.


So there ya' go...prime it and move on

John, I don't want to worry you unnecessarily but I don't think Vans knows exactly what the phenomenon is. And there is some small possibility that it could be an indication of a batch metallurgical defect rather than minor localised surface pitting (not likely...but possible) in which case "cleaning and priming" might only be window dressing. So if I was you I would go directly to Phlogiston Spars and ask for a professional metallurgical opinion on the specific cause of this defect. This is, after all, the most structurally important member in the plane. You want an expert opinion...not a guess.

You might then like to report back to this group.

Not long back I found that the AFP electric fuel boost pump supplied by Vans was not assembled in accordance with the drawings and one of the fuel lines conflicted with the fuel filter. When I contacted Vans about this they told me to "back off" a pipe thread connector and manually realign the tube.

However I felt that this was not good aviation practice so I went to AFP (Air Flow Performance) the manufacturer of the pump. I received a response from the head honcho and number one design guru himself, Don Rivera. He said that not only was it bad practice to back off the pipe thread but that it would invalidate the warranty.

Many builders assume that Vans is the fount of all knowledge in matters pertaining to aviation...but that is not necessarily the case.

[osxuser]

Originally Posted by william weesner

when i got my kit it had a slighty damaged spar and vans said polish it out ....i didnt buy at the slightly damaged price and didnt want a slightly damaged spar long story short i got a new spar. like bob said

"Many builders assume that Vans is the fount of all knowledge in matters pertaining to aviation...but that is not necessarily the case."


vans always says build on. i wonder what would make them say whooooa man you gotta fix that . sometimes i really understand what experimental means

It's YOU thats building, and your *** on the line, not theirs. Experimental means just that, people think Van's has their best interests in mind, when in fact, they just want to get away without replacing a bunch of parts. That costs them money. Cessna has much the same attitude, but the FAA gets in the way sometimes for them. That is why they are experimentals we build, not certified airplanes. You decide what is safe, not anyone else.