Cleaning corrosion from fuselage interior

You're absolutely correct! 

I'm fortunately that Vernon put me on the right path by telling me to have pieces of wood ready for the tail crawl. Of course that's only a tiny bit of all the help I've gotten from Vernon.

My greatest difficulty was crawling in and out through the seat back frame. Awful, awkward experience. And later I ended up removing the seat back frame so that I could remove the "window protector" inner fuselage skin and had a forehead slapping moment of, "Oh my God I should have removed the seat frame a long time ago!" the access to EVERYTHING in the tail cone and fuselage is so much better with the seat frame removed. Next time I'll know that whatever time is spent removing parts for better access isn't wasted. Better access means I can do a better job, plus it'll be easier and faster in the end. 

You might want to put some boards or plywood back there first, and possibly a moving blanket or old sleeping bag to cushion your knees and butt a bit. Cheers,

Boy oh boy will I be happy if I don't ever have to crawl back into the tail cone with a sack of rattle cans, all suited up for painting! 

Another big concern of course was the infamous steel wing attachments on the center section main spar. Turned out that at some point, someone removed & beautifully refurbished the fuel tanks - and primed the front of the spar while they were at it. But the rear, being blocked by the landing gear, hasn't been touched. Borescope revealed the the rear steel hardware was surface corroded. Still airworthy, but needed attention to remain that way. So we removed the main gear one at a time to clean up the rear of the spar, apply corrosion treatment, and prime it. 

Of course while you've got the MLG off you just KNOW you should rebuild the strut, replace the old stuff brake hoses, maybe replace some obviously nonstandard hardware she picked up over the years... It all seems to snowball. 

The Alpha Aviation MLG strut STC and gear spacer STC are excellent kits and made a huge improvement.

Sorry for the different camera angles but this is the same center section area shown before and after. 

 

 

It's not easy to shoot paint in this area especially once there's a good paint mist building up! Lots of evidence here of missed spots and weird overshoots.

Over the next few days I finally broke down and removed the windows and the fuselage inner skins that protect them. Wow - I should have done that in the beginning because it grants MUCH better access to the center section! Since these above photos were taken I cleaned out the rest of the center section and primed all the way across.

And of course it snowballs because... with the windows & inner skins out... now that I notice it these window welts look pretty ratty and it'll never be easier to replace them than it is right now. 

Update: scrubbed a lot of corrosion out but in some areas I couldn't get *everything* without going deep into sheet metal. Still, got it pretty clean in comparison and my A&P gave it his "good enough" approval. Scrubbed out the tail cone with Simple Green Extreme Aircraft Formula until water wouldn't break, alumiprepped the area, and primed.  

The primer dried out looking a bit blotchy which is exaggerated even more with my camera flash, but apparently this isn't usual as it reacts with a non-perfect surface. Went 77 years with no primer at all so hopefully this is good enough to get some more decades out of the coupe.

Before...
  

Halfway done...
 

Thanks Warren!

Perfect timing on this message. I just got back from the hangar, finishing the job of removing almost everything aft of the yokes.

My A&P suggested Alumiprep which I purchased but haven't yet used. I'm glad to read that you agree! My tail cone & center section contain decades worth of fogging oil residue caked with grime so we've rendered it safe to pressure wash. I did try cleaning up the area around the control mast with a 3M Roloc Bristle Disc which works wonderfully. I'll be interested to see how many discs I eat through by the time I'm done.

The coupe has even more holes now because we're installing the center section & elevator inspection plates. Those should help with all this pressure washing, alumiprep, and priming.

Aircraft Spruce Bonderite C-1C 33 ARCO