Sunday, March 19, 2017

Sunday Trailer Progress

I made much progress today! The replacement piece I mentioned yesterday, and its smaller friend I fabricated last week, were installed, along with the piece of channel that belongs at the edge of the floor. Before and after photos, though not from the  same angle, can be seen below.

March 5, showing damaged sections and opening
Today, with replacement sections in place and skins reattached
A bit of interesting (at least to me) science: The areas in red circles in the "before" photo show up as shiny in the "after" photo, because the aluminum alloy of the new pieces is much shinier than the 68-year old pieces adjacent to it, which have oxidized to a dull gray. Iron oxidize to form iron oxide, the reddish material we call rust, and will continue to rust away without further treatment.  The surface of aluminum oxidizes to a thin layer of aluminum oxide, but that layer protects the unoxidized aluminum below. This is why unpainted aluminum trailers, like Airstreams, are often polished - but must be treated with a protective sealant or repolished periodically. Polishing removes the layer of dull gray aluminum oxide to reveal shiny aluminum again, but the cycle of oxidation will start afresh without added protection. It should be noted that the older aluminum trailers (Airstream and contemporary imitators) could be polished to a much higher shine than modern Airstreams because they were skinned with 2024 Alclad, in which a sheet of 2024 alloy aluminum is coated with a very thin layer of pure aluminum. Modern Airstreams are produced with, IIRC, 3003 alloy aluminum, which aren't as shiny, but still have a pleasant sheen.

To get the skins reattached involved much drilling and temporary attaching if aluminum pieces via small devices known as clecos (named for the Cleveland-based company that created them), or panel holders. Nearly every hole has a cleco installed in it to make sure everything lines up. After everything was checked and double checked, most of the clecos were removed and a polyurethan-based sealant was applied where the panels were to join. Then I used Olympic rivets, a blind (pop) rivet that mimics the look of the solid (bucked) rivets used elsewhere on the trailer's exterior. Each rivet got a dab of the sealant on it to make sure it sealed watertight upon installation, and excess sealant along panel seams and at rivet holes was wiped away using rags wet with mineral spirits.

Aluminum skins temporarily attached with clecos.
Note the annoying dent in the panel is still present,
though much reduced from when I first acquired the trailer.
Alas, I have no pictures to show. I finished up about 9 PM, long after darkness had set in, and just a few minutes before the battery-powered work light ran out of juice. I still have to go back and cut off the remnants of the rivet shafts then apply a special tool to clean up each rivet head. I could have grabbed a fresh battery or an extension cord and kept working, except the special tool would make a lot of noise and I don't want to be the noisy neighbor.

If weather cooperates I may get that done tomorrow. If the weather is warm but rainy I will likely only be priming the steel; that steel needs to be primed and painted before the wheel wells and next section of plywood floor can go in. If it is especially cooperative I may be able to also address that ugly temporary patch you see on the right center of the above photo, and replace it with a real patch made from aluminum. The patch that had been there before, that came with the trailer when I purchased it, had been extremely battered so was removed.

It is starting to feel like I'm making real progress again. By the end of April I hope to have all of the new plywood floor in and the trailer weather-tight again, something it hasn't been since who knows when. Then comes all the rest of the stuff to turn it into a road-worthy trailer and a viable camper: brake lights, wiring and electrical, insulation, the minimal plumbing, reinstallation of the inner skins (inside walls), and the furniture. Whoo! That's a lot of work still to be done, but weatherproof and a good floor will go a long way to making that possible.

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