Found: A Welded 6061 Longeron Angle

Here's what a welded 6061-T6 aluminum angle looks like. This came with my April 2012 fuselage kit for a longeron, and I don't need it. Since I'm building up the basic fuselage structure, I made a current inventory of the angles and found this.

What we're looking at is a weld that was made to make the angle longer.

When 6061-T6 is welded, it's never as strong as it was. Typically it's half or a little over the original strength. One of the aerospace companies I consulted for had a special proprietary welding process for 6061 that recovered almost 60% of the strength, and that was the best I've seen.

So keep your eyes open!



In this view, you can see that the added part isn't even straight.



And here's the other flange.



I sent these photos to Van's.

Dave

It looks like that weld was done pre-extrusion?

I see porosity at the edge of the weld, scary stuff there, thanks for sharing.

Wouldn't be pre-extrusion. Aluminum billets 6-8" diameter and several feet long are pre-heated, pressed thru a die (think play-do fun factory). A couple feet is extruded, stopped, coupled to a puller that tensions the extrusion to keep it straight and then a couple hundred foot piece is extruded over a roller bed conveyor. Lengths are cut on the fly. Don't know what that mark is.

Good catch. While it looks very much like a weld, I wouldn't totally discount it being a defect in the extrusion while forming.
If it is a weld, it is a poorly done weld at that. If you wanted to invest the time, you could cut a cross section and die it.... it would readily show a weld vs some other anomaly. Doesn't really matter... that part won't fly!

What's not clear to me is; did this come from Vans or did you purchase the kit from someone else?

If someone welded this after extrusion, then why do mill marks extend through the "weld"? If it were even possible to weld before the extrusion, why is there still splatter? It doesn't look like a bad weld to me--I don't see the porosity, just some splatter that could be cleaned easily. Why does the bend seem gradual rather than abrupt? To me the pictures look more like someone attempted to bend the angle by applying heat along a line, but it seems unlikely. Curious to hear whatever you learn about this.

Not a Weld

From a guy who deals with extrusions everyday, that's not a weld. That's the spot in the extrusion where one billet ran out and another started. Normally that spot is removed by the extruder. It could have come from any extruder as they all do structurals the same way. My guess is it was missed by the QC Department at the extruder.

For what it's worth, I wouldn't use that as a longeron.

PaulR said:

From a guy who deals with extrusions everyday, that's not a weld. That's the spot in the extrusion where one billet ran out and another started. Normally that spot is removed by the extruder. It could have come from any extruder as they all do structurals the same way. My guess is it was missed by the QC Department at the extruder.

For what it's worth, I wouldn't use that as a longeron.

Click to expand...

I second this!!

And would want an answer from Vans. That part is not safe for use and would not satisfy the C of C for that batch of extrusions.

Mel, yes, this came from Van's as part of my 2012 RV-3 kit purchase.

I've contacted Van's and they are looking into it.

This section of the extrusion is NOT going into an airplane.

Dave

Paul Rose nailed it.

Van's checked with one of their suppliers and while they weren't certain (having only my photos at hand, not the extrusion), that's what the supplier thought it was too.

If I use it at all, I won't be using this nonairworthy portion of it. I think I'll save it as a nice souvenir.

Dave

David Paule said:

Paul Rose nailed it.

Van's checked with one of their suppliers and while they weren't certain (having only my photos at hand, not the extrusion), that's what the supplier thought it was too.

If I use it at all, I won't be using this nonairworthy portion of it. I think I'll save it as a nice souvenir.

Dave

Click to expand...

And they sent you a new one too, right?

When I initially contacted them about this, I told them I didn't need one and wasn't asking for one. Here's why.

Dave