SonexBuilders.net

Hello all,

Any of you builders gave the wing structure a coat of anti corrosion primer before closing it? or perhaps even before riveting the single pieces together, or left the aluminum sheets as they came? Or have you used Corrosion-X

Thanks for your help.

Roberto Grassi
Sonex Legacy kit #1433

Roberto,
I left the sheets as they came. 6061-T6 is pretty corrosion resistant. Most antique cessnas have no primer with their 2024-T3 alclad and many of them have lasted over 70 years. I restored a 1946 C140 and it had some corrosion issues, but 1946 was a long time ago. Primer adds weight, cost, and time to your project.

Others I am sure will have a different viewpoint.

From the build log pictures - my builder used zinc chromate primer on all faying surfaces in the wing and tail feathers.



During a wing repair I did same.



I also Corrosion-X anything else I can get to. Just this week during the Condition Inspection - after the empennage was cleaned and inspected it was wetted down with Corrosion-X. I also injected the main spar box with same.



I am located on the coast and fogging with Corrosion-X or ACF is a way of life. And while it is true that Piper and Cessna did not use primers inside their planes (well Cessna did on their floatplanes) - they are built of heavier gauge material than these LSA's. They can take a little "frosting" - for us - that's the beginning of something serious!

GraemeSmith wrote: And while it is true that Piper and Cessna did not use primers inside their planes (well Cessna did on their floatplanes) - they are built of heavier gauge material than these LSA's. They can take a little "frosting" - for us - that's the beginning of something serious!

The C140 I restored had a lot of 0.020 and 0.032 in it. But some parts, like spar doublers and landing gear structure, are heavier.

If I was going to prime, I'd do like Graeme's builder did - a light coat on faying surfaces.

Considering Graeme is outdoors on the coast, what he has plus the corrosion-x is a good thing. I'm in the Midwest, and in a hangar. So it depends on your situation as well.