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Starburst (Not the candy)

ShortSnorter

Well Known Member
Has anyone seen this around the shop head of a rivet? Does it have something to do with anodized surface?

Disclaimer: As with most photos, the details look more exaggerated. In other words this is difficult to see unless the light hits it just right.

ienuwl.jpg

11aiudi.jpg
 
Starburst

Yes, and I assume yes since I've only seen it on anodized surfaces.
Also, next time you set a rivet with the squeezer, watch and see if you spot a little puff of smoke. I would love to know what that one is.
 
Yes, and I assume yes since I've only seen it on anodized surfaces.
Also, next time you set a rivet with the squeezer, watch and see if you spot a little puff of smoke. I would love to know what that one is.

I immediately noticed the puff of smoke when I started using my squeezer. I'd love to hear an explanation for that!
 
Yes, and I assume yes since I've only seen it on anodized surfaces.
Also, next time you set a rivet with the squeezer, watch and see if you spot a little puff of smoke. I would love to know what that one is.

Don't breathe it in. That's the chromate coating coming off the rivet.

To comply with AN Standards, the manufacturers must put a protective surface coating on the rivets. This may be zinc chromate, metal spray, or an anodized finish.

The protective coating on a rivet is identified by its color. A rivet coated with zinc chromate is yellow, an anodized surface is pearl gray, and the metal sprayed rivet is identified by a silvery gray color. If a situation arises in which a protective coating must be applied on the job, paint the rivet with zinc chromate before it is used and again after it is driven.
https://monroeaerospace.com/informational-rivets.php
 
The puff of smoke is intense momentary heat created by the molecular friction generated by the rivet squeeze.
Seriously.

The radial lines are gravity lines radiating from the worm hole singularity you created when you squeezed that rivet. See INTERSTELLAR. Congratulations. You squeezed the perfect rivet.
(Not seriously. :cool: I have no freakin’ clue.)
 
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The puff of smoke is intense momentary heat created by the molecular friction generated by the rivet squeeze.
Seriously.

The radial lines are gravity lines radiating from the worm hole singularity you created when you squeezed that rivet. See INTERSTELLAR. Congratulations. You squeezed the perfect rivet.
(Not seriously. :cool: I have no freakin? clue.)

For 2 nanoseconds I thought I had something to brag about. :rolleyes:
 
Smoke

That's probably why I no longer require a squeezer to set rivets. I just pinch them between my fingers. Weird superpower I know.:D
 
I got this when I set the first couple of rivets on the webs to the fuselage center section halves. After that, I put the manufactured heads to the anodized part and It didn't happen anymore.
 
I got this when I set the first couple of rivets on the webs to the fuselage center section halves. After that, I put the manufactured heads to the anodized part and It didn't happen anymore.

I considered that until I reread the note below in the plans. Nothing in the plans jumps out out me as the reasoning, but as always you know Van's put it there for a reason.

1552t15.jpg
 
If you inspect the pre built spars and center sections carefully you will see that they are full of examples of these radial cracks in the anodizing. Van's has confirmed this is not a problem ever since they started selling prebuilt anodized spars as an option way back when.
 
Anodized aluminum gets an acetate sealer applied to prevent the fresh unoxidized surface from corroding. It is also during the seal process that colors get added to the surface. It is fairly brittle and cracks when the rivet swells.

Alumina is another name for aluminum oxide. It is white and is removed by the electrochemical process of anodizing. The remaining metal after anodizing is nearly oxide free and must be protected (sealed) or it will immediately oxide on the surface.

You are seeing cracks in the acetate seal. It is very unlikely that this is in the base metal. Yes- this is a place where corrosion can begin.
 
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