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Do the no-primer people wash or polish their parts?

guidoism

Member
After several years of them getting dusty I'm finally getting ready to rivet my wing's ribs into place. I've chosen not to prime. I've wiped the years of dust off of them but should I be doing something else before they go in?

Wash with mild soap and warm water?

Polish with aluminum polisher?
 
Polish with aluminum polisher?

Polishing will remove the alclad corrosion protection .. best to just leave as-is if you aren't going to prime. Maybe clean with soap and water if they are really dirty ...
 
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Alodine Pen??

If not priming, I would use an alodine pen on all the joining surfaces in the wing. Quick and easy, and good for areas that might see moisture :( such as the lower wing skins to ribs over the years.

These pens are pricey, but super handy and last a long time (so long as you don't leave them uncapped overnight). No fuss, no muss, no cleanup.

https://www.aircraftspruce.com/catalog/cspages/touchprep.php -- good to read the descriptions and comments.
 
I alodined everything small enough to dip. The faying areas of the skins (that contact the rib flanges) and the rib flanges of ones too big to dip-alodine, I sprayed with a layer of zinc Chromate or self etching primer (not epoxy). Idea is to give a little extra protection to the areas that can trap moisture, as others mentioned. Priming those lines is fast, easy, lighter than anything else short of alodine, and relatively cheap.

Whatever you do, clean well the parts you intend to coat.

Charlie
 
Boshield

I will start a debate. Any surface prep, including Alclad, is likeley to be compromised during assembly. Boeshield is made to spray and wick wherever the scratch is hiding. So why not save all the prep and take the Cessna approach ( bare Alclad ) with Boeshield where moisture is possibly trapped ?
 
Boeshield use was one piece of the advice given me by an aero engineer/multi-builder. Another was that alodine has the same or better corrosion preventative abilities as virtually any paint/coating. (He tested the alodine theory against misc coatings with multiple 2024 test tabs, wedged into a 2x4 & periodically dipped in sea water over many months, at a location in FL about 30mi from the ocean.)

Charlie
 
Polishing will remove the alclad corrosion protection .. best to just leave as-is if you aren't going to prime. Maybe clean with soap and water if they are really dirty ...
Polishing does not remove the alclad protective layer. It polishes the alclad protective layer.
 
Polishing does not remove the alclad protective layer. It polishes the alclad protective layer.

No expert here, but seems like you could get into the alclad, it's amazingly thin:

0.016 skin = 0.0008 cladding
0.025 skin = 0.0013 cladding
0.032 skin = 0.0016 cladding
 
I will start a debate. Any surface prep, including Alclad, is likeley to be compromised during assembly. Boeshield is made to spray and wick wherever the scratch is hiding. So why not save all the prep and take the Cessna approach ( bare Alclad ) with Boeshield where moisture is possibly trapped ?

Boeshield is a good product - respray every 5 years or so? ACF50 is another product that does the same thing. The assembly is sprayed when finished.
 
Corrosion X

Probably shouldn't use corrosion inhibitors prior to painting. If spraying inside the wings or fuselage, the joints will weep for some time. CorrosionX is clear and ACF-50 is red. I have had good luck with both products but prefer CorrosionX...
 
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