2001 Bambi belly- corrosion, shocks, disk brakes

[mswartz]

Prefacing this post by saying that I intend to keep this trailer for a long time. Was hoping to be out on vacation with it at this time of the year, but the trailer condition dictated otherwise. Pre-trip inspection results have kept me at home, at work and spending money.

I'm replacing all the belly below the beltline and much of the insulation on my '01 Bambi. This is due to (1) sagging belly from the aluminum rivets falling out as they corroded apart in the steel frame, (2) the aluminum belly corroding out where it was in contact with the frame, and (3) the corrosion on the frame from gaps, missing rivets and corrosion holes in the belly.

The shocks and axle were removed, due to the shocks being rotted and the need to remove the axle to clean it up, to remove the remainder of the bellypan and to access the rusting frame for cleanup and paint.

I purchased new A/S shocks, and scraped, primed and painted the axle. It is now waiting for the belly to be done. The frame is in pretty solid condition, but will require alot of rust removal and alot of clean/prime/prep/paint. Then fiberglass insulation in all the right places.

For the bellypan material, I've got to decide if I'm going to go with the 5052 aluminum sheet for the central parts. Anyone have any experience using the 5052 for the belly? I would like to go with all 304 stainless, but probably can't afford it.

I've already decided to go with 22 gage type 304 stainless to replace all the dark grey aluminum transitioning from the belly wrap to the frame. Anything thicker will be hard to form, and lighter may not be suitable.

All belly metal will be isolated from the frame by butyl or neoprene rubber, and attached with either stainless rivets or stainless screws, all with rubber/stainless washers under the heads. Any suggestions on the isolation material? I was thinking of using either 2-in wide Scotch 23 tape, or some kind of butyl rubber, but whatever it is I want it to keep a sealed gap between the painted frame member and the bellpan material.

While the axle was off, I removed the brakes and purchased the Actibrake with Kodiak disk brakes from Inland RV. Any suggestions as to mounting location of the Actibrake actuator unit? I am considering mounting it inside my trailer.

I found both outer tubes of the shocks nearly completely rotted out. These Gabriel units are not even lightly coated with anti-corrosion material and don't hold up well. Both shocks have been replaced.

While removing the shocks, after several days of penetrating oil and mechanical shock, all the 1/2-13 nuts came off the studs, except for the curbside stud on the axle ear. The thread sheared off the stud. I ended up grinding it down, boring out the existing stud and tapping to 5/16-18 thread and will use a grade 5 bolt/washer combo to replace it.

I also removed all the propane line and will replace all of it. I've purchased all new 3/8 and 5/8 copper tube and all the fittings, along with new type 316 stainless clips with neoprene jacket. Many, perhaps half, of the plastic-coated clips that were screwed into the belly, some into the frame, corroded out and were either loose or missing entirely. The propane line running from just in front of the curbside wheelwell had been rubbing against the bevel-cut forward edge of the axle mounting plate, and had nearly cut through the copper. It had also crushed the line and could have been one reason for my frequent gas-operation problems with the refrigerator.

Having lived in the Northeast with the Bambi since it was new in Sept 2000, the road salt and salt air (I live near the ocean) takes its toll. However, I still get mad that the frame of my Bambi was so poorly painted by the vendor that it rusts as it does.

Any and all comments/suggestions would be greatly appreciated.

[Killo1]

Marshall.
As you know, salt water is brutal on metal. None the less, I think you should start working for Airstream and help them with small, but significant improvements as you had mentioned. I love the way you think.
If you feel brave may I make a few suggestions?
Pull the whole frame and have it professionally powder coated. That should hold up a long time in your environment. If the powder coating is prepped correctly the powder coat is great barrier. You also might try Emron, but you would need someone to beed blast before you paint with the Emron. Emron is a great two part paint/epoxy. Used in aviation alot as a barrier for magnesium and the elements.

Secondly, use stainless tubing for your propane. It would take a little more work, might need to rent a pipe threader and bender but it would be bullet proof.
Keep up the good work. Try to throw in some pictures if you get a minute. Would like to see your work.

[mswartz]

Alan, thank you for the suggestions. I cannot afford the money and time to pull the frame for powder coating, although I agree it would be a great solution. I am using the Pettit Paints polyurethane marine coating system with 6980 Steel Primer on clean steel as the base, as I've used this before and it has held up well in salt spray environments. It requires lots of attention to surface preparation, as most coatings do. Also, a good suggestion on stainless tubing for the propane. I have access to the threaders and benders for stainless tubing and if I have a few dollars left over, I would like to go this route.

An update: A few days after my July post, I had to get back to work (ie, what I get paid to do) and with travel away from home for so long I haven't been able to get back to the Bambi until a few days ago. It has been sitting up on blocks, axle off, awaiting attention. A sad sight.

Unfortunately, I leave in two days on another business trip, and have had only about 12 hours toward getting the frame area over the axle prepared, and have that cleaned and painted. With that done, my next steps are to get the axle/brakes/wheels on to allow me to move the trailer indoors for work over the winter.

Any suggestions on locating the Actibrake controller? I am leaning on an interior installation.

After that, the remaining action items are:
1) selecting the insulation for under the floor (I've browsed the discussions over fiberglas/reflectix/none);
2) fabricating belly pan sections from the stainless steel sheet;
3) deciding on isolating material between the stainless bellypan and the now-painted frame;
4) finishing cleanup, prep and painting of the remainder of the frame;
5) removing the 120VAC power cable, installation of 120VAC 30A inlet on exterior wall;
6) insulation installation;
7) bellypan installation.

At this rate, I should be done by February. Given the weather here in New England, that is optimistic.

Thanks for any suggestions.

[markdoane]

Marshall,

5052 should be a good choice for the bellypan. It has good resistance to saltwater. I'm using .032" 5052 for the bellypan (and wraps), but I don't live near the ocean, and I haven't had it back on the road yet.

[LI Pets]

Not sure if the rubber will hold up and remain in place, but is a great idea.

The SS belly pan is not worth the money if you're trying to save $$ use the 5052.

What I'm doing is using POR 15 on the mating edges of the bannana wrap the the frame then coat that edge again on the other side where it will meet the belly pan, when that edge will be painted.

The bottom line is that all contacting edges with be painted.

Also to reinstall the fiberglass is asking to redo all this work again. I suggest the the foil bubble R 14.5, it will not absorb water and sit there soaking and rusting everything like the fiberglass pink stuff.

[mswartz]

Mark and Bob,
Thanks for the comments.

I already have the stainless sheet since I got a great deal from a vendor I know. It was less expensive than the 5052 I was originally looking to get.

Good idea on overlap painting.

I agree on the concern over damp fiberglas, and am leaning toward the "reflectix" type sandwich insulation, stood off from the plywood by 1-in square stock to allow the air space.

Since bubble-foil primarily works by reflecting radiation, and since the floor is not the primary heat sink/source of the trailer, and since I don't want to trap transpiration moisture between the foil and the floor, I'm going to leave some- as yet undetermined- open gap on the standoff material perimeter within each segment of the frame which I hope will allow some reasonable ventilation without excessive circulation. Any thoughts?

[LI Pets]

This is worth reading about foil
And installation guide

See the crawl space guide, I would use styro cut into 1" x 1" furring strips, using liqiud nail to hold it to the wood??

It can be glued stapled (I would use SS) and zip wrapped around pipes.

[Tim A.]

My intermittent checking on the Forum makes my addition to this thread a little late, but perhaps it can help anyway. As a result of repairing-restoring a small aluminum rowboat my Dad built in about 1950, I have had to learn something about aluminum corrosion. From what I have learned, I would suggest that the corrosion has mostly been due to what is called galvanic or "electrolytic" corrosion which is a consequence of aluminum or another metal "sacrificing" itself for other "more noble" metals. The problem is well-known with boats where, for example (example is from the West Marine catalog), a stainless-steel prop shaft will corrode while the bronze prop attached to it will remain intact. Any salt in water greatly accelerates the galvanic reaction because salty water is a much better electrolyte than pure water.

Living near a seashore has many benefits, but one of the disadvantages is that salt from seawater is in the air in aerosol form and will collect, sort of like dust, on most anything. Rain or any water will dissolve that salt and carry it into almost any crack or open space. The belly pans of our Airstreams are not water tight and will let wash water, rainwater, and splashed water in. If the water dries, but does not drain out, the salt will be left behind after the water evaporates. Repeat the process several times and much salt remains and you have an even stronger salt solution the next time water enters.

In another thread, I mentioned drilling a number of small weep holes in the belly pan of our 2002 Bambi to help trapped water drain. Draining water out is more effective than drying it out because no or less salt is left behind. Fiberglass insulation might help the draining process relative to bubble pack or styrofoam because those materials can also trap water whereas the fiberglass is very permeable.

[kwsailor]

Tim A.Glad to hear from someone with boating experience,I live aboard,and travel with a 1999 Bambi.What do you think about installing zincs on several places on the frame or other places?David Quinn

[2airishuman]

Originally Posted by kwsailor

...What do you think about installing zincs on several places on the frame or other places?...

hi sailor...

post 8 above relates to another unrelated form of corrosion,

NOT the filiform or surface corrosion common to a/s skins and exterior aluminum or chromed bits....

we covered this some in another LONG thread on corrosion...

see posts 10/16/28/29 here, and read some of the background links included in the thread...

http://www.airforums.com/forums/f142...tml#post374890

cheers
2air'

[Tim A.]

Originally Posted by kwsailor

Tim A.Glad to hear from someone with boating experience,I live aboard,and travel with a 1999 Bambi.What do you think about installing zincs on several places on the frame or other places?David Quinn

I don't think installing zincs on an Airstream would prevent any form of corrosion, whether it is filiform or galvanic corrosion. For it to be effective would probably require that the Airstream is immersed in water. None of us wants that!