Just curious if Barth coaches have any common trouble spots with corrosion.

I'm extra curious about possible galvanic corrosion between the steel chassis and the aluminum coach body. Since aluminum is less noble, it will tend to sacrifice itself to the steel over time. Does Barth isolate the aluminum from the steel? Any issues along those lines? Any horror stories out there?

Thanks, Tom W.

Tom,

Hunt through the archives here.......

Lots-n-lots of discussion, including various methods of slowing it down.....(Can't change the laws of physics, but there's ways to push out the timetable......)

Thanks Lee:

I did a search on corrosion...came up with 5 pages. Most posts dealt with the storage compartment doors or the more superficial stuff. I'm more interested in the major structural connections between chassis and body. Anybody know what types of fasteners are used? What size and type of aluminum structural member is actually secured to the chassis? I guess I need to get under one and look.

BTW...I deal with corrosion induced structural failure of aluminum a couple times a month. Yes...I'm paranoid.

Tom W.

quote:

I deal with corrosion induced structural failure of aluminum a couple times a month. Yes...I'm paranoid.

Tom, with that experience, maybe you could tell us what you do to treat corrosion and prevent a recurrence.

Bill:

Most of my experience is with aluminum seawalls. The most serious failures are the result of anchor-rod corrosion. In almost every case, the aluminum rods were used as rebar chairs inside reinforced concrete caps. AL touching FE, differing electrical potentials, AL is the anode of the coupling, AL turns into aluminum oxide. The lesson is...avoid these types of couplings, especially in structural applications. Just curious if Barth coaches have ever had these types of problems.

Tom W.

Tom:

I have a 1973 from the eastern part of the U.S.. Some of the pop rivets let go and I put in new ones. At the bottom of the skin there is some pitting on the skin where it is connected to the steel frame but the loss is not much, 20% of the metal at the most.

Most of the he skin is connected to an aluminum subframe, take a look at the build pictures Dave has on this site to see what is under the skin.

Based on my 30+ year old coach from the land of salted roads my feeling is there is not a problem.


These are motor homes, not boats or sea walls thank god and if you find my posting from a year or two back where I said to check your zincs, I was joking.

My skirting is supported by 1 inch steel tube framing. No problems so far, but I shoot it with Boeshield now and then.

My only corrosion issues have been regular blistering under the paint. They did not do a good job etching and zinc chromating like they should have when they painted it. Having been almost everywhere on mine, that is one of the few criticisms I can make about Barth quality.

Timnlana:

That's about what I figured. Since AL and FE are fairly close re electrical potential, it would take a very long time for problems to develop. And...if the AL/FE interface is kept relatively dry, I doubt any serious problems would occur in my lifetime. That said...I always go to great lengths to isolate dissimilar metals in all of my new construction.

TW

quote:

My skirting is supported by 1 inch steel tube framing. No problems so far, but I shoot it with Boeshield now and then.

Like Bill the 1 inch steel box framing is the area that has rusted on my coach and the skirting is pop rivited to the bottom of this steel box framing. While the standard rivits have held up very well, they are all still tight where they were used, the pop rivits on the skirting have not. In fact I think I have replaced 70% of the pop rivits, I use SS rivits, aluminum is from what I have been told just fine, zinc plated steel rivits are not.

If there was a coating on this 1 inch framing it was long gone by the time I got the coach. Of the products available in Los Angeles I have found the red "Rust Buster" or whatever it is called paint from Home Depot works the best. I have used the "Extend Rust Treatment" paint from Loctite, it goes on nicely and turns the rust black, two coats appear better than one but unless I put paint on top loctite covering the steel rusts again, this takes about a year. Areas I have painted over the Loctite products do not show any signs of rusting again. I would use OSPHO but I can not get it in Los Angeles. I have painted some of this steel and there is no indication of the rust returning in the painted areas. The inside of the aluminum skirting I painted with some etching zinc chromate from the Z-Spar boat paint company that I don't think is made anymore, the aluminum does not show an activity so like Bill H. it is my guess that well primed aluminum does much to protect our coaches. Unlike Bill H. I do not live next to the ocean so I think his test environment is a bit more demanding, in California we do not salt the roads so I can not say how my approach will hold up in all areas.

One day in my copious free time I hope to put nylon washers between the aluminum skirting and the steel at the bottom to allow water to dain out, it does pool with the aluminum rivited directly to the steel.

Timothy