Corroded rivets Bay floor

[solardude]

As many of you know I have been busy preparing the 102C3's front Bay for the battery bank. Well as with everything so far on the bus, the scope widens. No surprise.

So I have all three bays cleaned out and have been busy scrubbing and degreasing all three bays so I could paint each of them to protect from corrosion and pretty things up. I have two bays done, Front Bay and the Rear Bay. Both look great factory new again. However, I think I messed up. On the Front Bay I did a thorough inspection of all the rivets as I was under the bus fabricating supports for the generator sitting in the old condenser bay. Well I was pleasantly surprised to find all but a small handful of the rivets still holding strong.

I'll skip to the bad part, I was rushed to get the Rear Bay done, and did not check the rivets.... Dumb.
virtually all the rivets joining the floor to the stringers are rotted off.

It dawned on me to check them as I was preparing the Middle Bay today, I had to replace almost every rivet in the middle bay holding the floor to the stringers.

I don't know why all these rivets have failed. They all look to have corroded in half.

The question is twofold:

Are the rivets just to hold the floor down, or are they structural in nature?

If they just hold the floor down, I can ignore it and not add an additional day of going backwards tomorrow to this project.

If they are inherently structural, I will need to tear out the insulation and plywood to drill out 200+ rivets.

Is anyone here an MCI Engineer or just know what keeps these buses going straight down the road with rotten floor rivets?

Going off to sulk, and hope for words of wisdom.
SolarDude.   

[Scott & Heather]

Our 102c3 spent most of its life down south so the floor rivets are fine, but our 9 literally has holes corroded through the aluminum floor. Have you tried to lift the floor to see if it's still attached?


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[bottomacher]

The rivets are structural in nature; they prevent twisting and sliding and other movement in the frame members, just as nailing the floor to the joists in your house. I can't speak to what amount of damage, if any, will occur without them, but I expect that the flexing will ultimately weaken other areas over time.

[solardude]

Postulating:
My bus also spent it's life in a warm climate from the looks of things. The bus really is in remarkable shape for being as old as it is. After pondering my Sunday afternoon activities (drilling rivets) and wondering why different rivets were not used I've speculated the aluminum rivets used from the factory are structural in nature for exactly the reasons bottomacher mentioned, I also think the rivets are sacrificial. While I was grumping about why MCI used rivets that failed before either of the substrates, I started to be thankful it was the rivets that failed and not the corrugated floor or stainless stringers as repairing either of those would be orders of magnitude more work.

So, now I can be thankful that I only have 1 extra day added to the PROJECT!

Well, Winter is coming so I better get to work!

SolarDude

[bevans6]

Aluminium reacts galvanically with steel, including stainless steel, particularly in the presence of an electrolyte like salty water.  There would have been a protective layer of something between the floor and the stringers, if only paint, but the rivets would be in perfect contact with the raw steel in the holes.  That is what makes them corrode first.

Brian

[jackhanow]

So I have some of that. the rivets are made by wuerth a German company #ad84bs they are $33.00 for 50 from mci. You'll need a heavy duty pop riveter. The flat layer is glued to the corrugated panels. They don't just peel off either but they can be carefully removed. Make sure the corrugated  panels aren't corroded through and also look in the ac compartment make sure the wall are still intact at the bottom