To Jack or to hoist? That is the question....

[Belegedhel]

I have reached the point in my airstream refurb adventure where I need to separate the shell from the frame of my '73 Globetrotter. From my research on the forums, it looks like those who can, lift the shell with an overhead hoist. For those of us without that capability, the common technique seems to be to brace the shell from within, jack against the bracing, remove the frame, and then support the shell with sawhorses or the equivalent supporting the bracing.

I am envisioning building sort of a double gantry frame over the trailer using 4x4s and appropriate bracing (see rough diagram below), and then running a 2x12 from endcap to endcap on the interior. I'll then run a ~36" threaded rod up through the roof vents, through the 2x12 and the straddling 4x4 with a nut on each side. These threaded rods will be used to lift the shell from the frame, and then to lower the shell once the frame is out of the way.

I figure that the cost of materials will be a wash as to whether I am building interior bracing and sawhorses, or overhead gantry structures. Besides, I still have to do the roof work (changing out the air conditioner, sealing roof joints, etc.), so I can use the gantry as my scaffold.

Anyone see any glaring idiocy in this plan?

[dznf0g]

I'm not sure you need the 2X12 running the length of the coach. JC, to this day, uses a hoist to mount the shell to the floor/frame. They just have a square(ish) jig that goes through the front and rear vent. The shell is relatively light and it can be supported by the framing around the vents.

[dznf0g]

Originally Posted by dznf0g

I'm not sure you need the 2X12 running the length of the coach. JC, to this day, uses a hoist to mount the shell to the floor/frame. They just have a square(ish) jig that goes through the front and rear vent. The shell is relatively light and it can be supported by the framing around the vents.

Actually, I need to modify a little. They hoist the shell AND the floor, assembled, by the hoist, onto the built up frame. You would need to cross brace the shell to keep it from spreading, but you can lift by the vent frames and neighboring rib, I believe.

[Belegedhel]

Thanks for the reply. The discussions I've heard from those who hoist indicate that the beauty of lifting from above is that they don't feel like they need the internal bracing. If I hoist it and was to then set it on the ground, I figure I might still need some kind of bracing, as the shell would be resting on the aluminum skin, since the skin extends below the C channels to cover the plywood.

[Wabbiteer]

Think box beam - a plywood skin over dimensional lumber - and you'll have something stiff enough to work around w/o flinching. There are a few examples pictured in these forums though a quick search did not reveal them to me. Very similar to an Airstreams' shell construction.

Basically some construction adhesive and a flock of screws to make two arches out of four ribs. The bolting, bracing and the 'feet' are details to carefully plan out - I went with building pedestals and cross-rails instead...

Remember you have to loft the shell above the wheel wells and that extra 14-inches or so is a thriller.

[FC7039]

You need to brace whether jacking or hoisting or your post shell off refit will be more of a challenge.

Look up Frank's Trailer Works for his wooden gantry.

[dznf0g]

Originally Posted by FC7039

You need to brace whether jacking or hoisting or your post shell off refit will be more of a challenge.

Look up Frank's Trailer Works for his wooden gantry.

I'm not sure your bracing would need to be as elaborate as it needs to be when jacking, but I think I would brace to prevent spreading of the sides and perhaps one horizontal cross brace to keep the horizontal plane "square".