Specs with embedded questions

[nuke]

Design goals:
- light weight
Need to be able to carry a lot of stuff inside

- highly insulated
For desert conditions, want to be able to last at least a little
while before turning into an oven

- demountable cabin
Retain use of trailer independent of cabin


Trailer:
- RedTrailer 4x8 or 5x8

If the 4x8 is chosen, I will want to build frame larger than
trailer bed to accomodate queen-size mattress with minimal fuss.
The weight difference between the 4x8 and 5x8 is surprisingly
small (255# vs 263#), so the main motivation for the 4x8 would be
to have the wheels be under the frame for looks and aerodynamics.


Plan is to put leveling jacks on 4 corners of trailer. Can they
be bolted on? Is the one that redtrailers sells
(http://www.redtrailers.com/ShowItem.asp?id=53610)`good enough, or
is there a better one easily available?

Floor:
- Construction

2x2 (or 1x4?) lumber with plywood skins and rigid insulation. An
open question is how thin can the skins be? Plywood is heavy.
I'm guessing that 3/8" might be enough for the top, and 1/4" for
the bottom.

Bottom will get the customary roofing tar treatment.

What about using the stake pockets in the trailer as attachment
points for the cabin? Drop 2x4 of the right length from the
bottom of the floor to slip into the pockets.

4x8 trailer necessitates accomodating the wheels in the floor.
How much room is needed? Is it worth trying to build the floor
thick enough to completely clear the wheels?

Would it be worth making the cabin a bit wider than the trailer
wheels and longer than the trailer bed, and attaching the leveling
jacks to the cabin floor, so that the leveling jacks can lift the
cabin off of the trailer? Or is that going to necessitate
building the floor a lot stronger than it would otherwise need to
be?

Walls:

Plan to use the Cub/Modernistic profile Make the main arcs by
laminating 1/8" strips as seen in the 'lightweight design' thread
on T&TTT forums, but make it 1 5/8" (nominal 2") wide. Frame the
rest with 2x2 (or 1x2 on edge?) and fill the voids with rigid foam
insulation sheet. Again the question is how light can I make it?
Is 1/8" plywood enough if epoxy-based boat hull paint is used to
finish? I have no need to sit on top of my trailer

Attach to floor with screws and glue. May need to accomodate
wheels in wall design too.

Galley/Rear Wall:

Minimal--see 'lightweight design' thread again. Do want to figure
out a place to install a PetCool A/C.

Ceiling:

1/8" ply on inside, 1x2 rafters, insulation (what's best here?
kerfing rigid foam, or trying to find flexible foam?) and 1/8" ply
on outside.

Galley Lid:

As for 'lightweight design' thread.

Doors:

As for sides, probably rectangular for easy construction.

Windows:

Like to find some double-paned ones for thermal efficiency.

Exterior Finish:

The Dr. Rot treatment as outlined by Mike.

{edited to remove preformatted tags}

[Juneaudave]

Floor:
- Construction

2x2 (or 1x4?) lumber with plywood skins and rigid insulation. An
open question is how thin can the skins be? Plywood is heavy.
I'm guessing that 3/8" might be enough for the top, and 1/4" for
the bottom

Sounds like you have done some reading and your well on your way!!!! One of the things that I have picked up is that most builders do not have top and bottom skins on the floor. I do..but I'm not sure that I would do it again. I used 5/4 ripped spruce with one inch of insulation, 3/8 on the top and 1/4 on the bottom. It's rock solid. I'm a thinking that you could easily get by with 1/4 and 1/4 or maybe less....IMHO

[angib]

If the 4x8 is chosen, I will want to build frame larger than
trailer bed to accomodate queen-size mattress with minimal fuss.
The weight difference between the 4x8 and 5x8 is surprisingly
small (255# vs 263#), so the main motivation for the 4x8 would be
to have the wheels be under the frame for looks and aerodynamics.

Beware, if using a 4x8, you would need not only the recesses where the tops of the tyres stick up into the body, plus a couple of inches for bump clearance.... but that recess needs to go all the way to the front and through the front wall, if you're going to be able to take the body off the trailer without a crane.

Andrew

[starleen2]

There has been much talk recently about de-mountable tears. IMO there are a PITA. Our first design was a de mountable to slide on and off. It was held in place by four bolts in the corners. It measured 5 ft X 6 ft. I was very awkward to get on and off – read – Not easy even with sloppy clearances. If the trailer is to be used for other purposes, then two more issues need to be considered – what to do with tear while it is off the trailer and what about another floor surface on the trailer? Our first designing – the tiny trailer had an expanded steel grate for the trailer floor. After sliding on this a time or two it would tear the subfloor, so we installed metal over the grating adding additional weight. Just something to consider. If the trailer is to be separated from the tear, then are stabilizing jacks attached to the trailer really necessary? Perhaps a few scissor jacks (i.e not attached) kept in storage might suit your needs better. I think that Jacks on the corners of the camper may be the way to go, however that may mean of lift of several feet to clear the trailer (and wheels if enclosed) Again something to think about. The idea of taking something off and on again is appealing, however think about aligning the stakes and bolt holes for securing the tear. Not saying that can’t be done. There are some (including us) who had done it. However, in my experience it didn’t work out. BTW, we now own two trailers, one hauling stuff and another dedicated to the camper.
Ps. Our weekender is 8X6 constructed of 3/8 ply (3/4 insulation) and weighs 1060 lbs

[nuke]

I was planning on having to raise the cabin quite a bit to lift it off of the trailer, but the more I think about it (and the more I think about what starleen and angib have to say), the more I think that maybe it's not a reasonable goal.

I also found out that I have a friend who's got a 4x8 trailer (just the trailer), so I have a way of hauling materials without buying one myself. Maybe this is the universe telling me I should go the lightweight way of just buying a set of wheels and axle and build the floor a little stronger, rather than buying an entire trailer.

[Miriam C.]

Not sure the Universe is on your side Nuke. Might want to add up the price of axels, wheels and springs, not to mention the wood to make it stronger, before you decide not to buy. OH and the price of metal for a tongue.

[Wolffarmer]

When the universe is speaking, shut up and listen.

[Nitetimes]

When the universe is speaking, shut up and listen.

Now Wolf, I really gotta wonder if in some cases that's really not such a good idea??


avatar pic

[capdabney]

http://www.rallymastercampingpods.com/.

This is what you're looking for... I know this guy from my Army Days in Kansas...straight up fellow.

This product he sells is built to your specs and yet allows you to keep the trailer for regular use as well.

Give him an call...I think you'll be suprised

Capdabney