Zinc Rot, What is it?

[JJ Skippy]

Looks like improper paint application. The outer paint. coat can crack without there being anything wrong with the zinc alloy used.


Unrelated, but same topic, many people say Magic 747s used to suffer from zinc rot, but it seems most issues were actually related to poor painting.

Disclaimer: I'm just killing time and don't really know what I'm talking about.

Would that also explain the paint bubbles too?

 

[Jazajia]

Would that also explain the paint bubbles too?

I think so. I have experienced paint bubbles on diecast fuselages after painting them for custom projects.

There are a lot of factors that can interfere with paint application. Paint properties, application technique, environmental conditions.

 

[Irish]

A friend of mine received a Gemini Jets Thai A340-500 (HS-TLB, GJTHA590, Sep 2005) and he observed paint cracking around the tail joint in the fuselage and horizontal stabilizers. There were also some paint bubbles scattered across the model (likely unrelated). Not sure if the cracks are zinc rot; he’s also wanting to know if the A346 is susceptible to it too.

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Looks similar to what one of mine suffered, I know Richard has a spreadsheet on all the ones susceptible to rot but doesn’t have all of them cause I don’t remember the GJ Delta 75th ann. on there. I would ask your friend to keep tabs on it and maybe see if it worsens over time.

 

[Phantom]

Paint bubbles can be the result of insufficient cleaning of the blanks before applying the base laquer. Especially when heated, the residue underneath the base may outgas resulting in bubbles.
I'd think the same effect can be prompted when the base coat is affected (softened/expanded) by excessive use of solvents (or their gases)