Is there corrosion between the steel frame and aluminum floor in Minuets?

[timzog]

Hi Minuet owners,
Is there any indication of corrosion between the steel frame and aluminum composite floor in the Argosy Minuets so equipped? I am planning on installing an aluminum subfloor and want to see if there is evidence of corrosion problems in the Minuets with composite floors, I have heard people complain of sagging issues but no mention of corrosion,
Thanks,
Tim

[perryg114]

I have wondered the same thing. I would say that there is a 100% probability that there is corrosion just like there is between the frame and the lower skin. The major factor is the pink stuff that holds water against the metal.

Perry

[cameront120]

I suppose you could always run a liberal beed of caulking along each edge of the top of the frame before seating the floor to prevent any moisture ingress.

[perryg114]

The floors maybe ok because the pink stuff sags and pulls away from the floor. The rear bumper plate area would be the one I would be concerned with.

Perry

[cameront120]

By the way, will the two metals need to be isolated from one another to prevent any reaction? Maybe some sort of gasket would be in order?

[Wayward]

There is always galvanic corrosion between dissimilar metals...the rate depends on the electrolyte the are in. Salt water is the worst but fresh water, salt air, humid air, road brine can get it moving too.

Stainless steel fasteners do not corrode. but SS is noble and can seize due to galvanic corrosion with aluminum in the right circumstances. A sacrificial anode is the only sure way to reduce it but are generally only used in water. The zinc or magnesium anode will corrode before the aluminum.

If you were concerned about this, a strip of soft zinc flashing between the aluminum and steel would probably last forever on the road. If you use rubber or sealant between them, remember that your stainless fastener will still be connecting dissimilar metals.

Two other things that will help are cold galvanizing paint (sacrificial also) on the bare steel and a sacrificial anti-sieze (Permatex Never Seez) compound on all stainless fasteners.

[timzog]

Originally Posted by Wayward

There is always galvanic corrosion between dissimilar metals...the rate depends on the electrolyte the are in. Salt water is the worst but fresh water, salt air, humid air, road brine can get it moving too.

Stainless steel fasteners do not corrode. but SS is noble and can seize due to galvanic corrosion with aluminum in the right circumstances. A sacrificial anode is the only sure way to reduce it but are generally only used in water. The zinc or magnesium anode will corrode before the aluminum.

If you were concerned about this, a strip of soft zinc flashing between the aluminum and steel would probably last forever on the road. If you use rubber or sealant between them, remember that your stainless fastener will still be connecting dissimilar metals.

Two other things that will help are cold galvanizing paint (sacrificial also) on the bare steel and a sacrificial anti-sieze (Permatex Never Seez) compound on all stainless fasteners.

Thanks for the excellent information. I wonder why I haven't seen anybody take any of these measures when attaching the belly pan. I have seen firsthand the extent of corrosion there and with the pink stuff resting on the belly pan it is probably the wettest part of the whole thing. I really like the idea of a sacrificial Zn layer somewhere.
Tim

[perryg114]

POR 15 is a very good insulating layer and it is tough stuff. Coating everything with it will help with corrosion. Taking care of leaks before they go on for decades is probably the best idea. Giving water a place to exit the C-channel is another good idea.

Perry

[mutcth]

I just sold my aluminum-floored Minuet. I can't say that I noticed corrosion problems from the design, but I also didn't look underneath it with the belly pan was off. The shop that did that work (Frank's Trailer Works) didn't mention anything odd either.

Tom

[perryg114]

You mean 62Overlander Frank? Maybe we should ask him since he restores them.

Perry

[mutcth]

Yep - one and the same. He was up close and personal with the floor in my trailer because he had to replace cross members that had rusted loose. (Their failure was due to a stupid small gusset design rather than dissimilar metal corrosion.)

Tom