A load of Newbie questions

[angib]

....substitute aluminum for plywood and steel for 2x4's where ever possible.

I think you could usefully reconsider some of these choices - in both cases, I reckon you're replacing a lighter material by a heavier one!

Because plywood is much lower density than aluminum, you get more thickness for the same weight and that makes it much tougher.

2x4s belong in houses, not small trailers. You only need more than 1x2s (or even 1x1s) in a few places, like the beam under the hatch hinge. Any steel you put into a trailer will be heavier than the equivalent in wood, except for the frame.

Andrew

[jaeson]

Alrighty,

Thanks Ira & Andrew. I didn't mean replace all the required plywood with aluminum though. And yes, I can see why 2x4's is overkill. I guess what I was trying to do was avoid having to stain all the wood, I wanted the aluminum skin for convenience. Also I will likely end up airbrushing it.

I suppose in the end I wanted it to look more like a tin can than a wooden shack. Perhaps I am going off track here again, since that will just end up adding extra weight to the design. I was doing some weight comparisons at Home Depot the other day, and I came to conclusion that steel (1/2"x2"x12') was lighter, but of course, I was comparing that to 2x4x10's and not 1x2's. I guess I will have to reconsider.

Go for the wood, but then, what wood? Lightweight I'm thinking pine, but 1x2's in pine, is that sturdy enough?

PS - Going to check out Metal Mart today!

[jaeson]

So, I'm thinking cedar now. Living in BC, I should be able to find lots of it!

So what about the curves in the frame, should I consider steaming and bending my 1x2's?

[Ira]

Is cedar lighter than pine? And cheaper? If you can get that, cool.

And yeah--1 by 2 pine is PLENTY strong. But some of use here, like me, bought the more expensive select pine, because it's easier to find straight pieces. For roof spars, a lot of use 1 by 2 poplar, but again, pine is FINE--but especially for the roof spars, you really want those straight so they don't bow up and down.

I used 3/8" ply for my walls, 1 by 2 pine for framing, and 1/8" paneling for the cabin walls. Once that's all put together with insulation, it's like a ROCK. It's not going anywhere.

Also, so many of us overbuild, and although 1 by 2s roof spars properly spaced apart is plenty strong, nuts like me doubled each one up--because we were paranoid and thought we were building a tank instead of a TD. In addition, Andrew mentioned the thicker hatch spar, that last spar which will support your hatch:

You can use that same 1 by 2 material--just glue and screw a few pieces together.

If you want the tin can look instead of a woody, you can always paint with aluminum paint that's meant for wood. It won't look as good as a real aluminum skin, but you're saving the weight of an extra skin.

But if you're building a 4 by 8, and with your vehicle, you can build a lightweight conventional TD out of wood and STILL skin with aluminum.

But what do you mean about the curves in the frame and steaming? What part of the TD? There are only rare instances when you have to steam anything, and I sure didn't. Do you mean the framing for the top of the walls?

If so, you don't have to steam for that. You just cut small pieces and butt them. Some folks even use 3/4" ply.

[jaeson]

Is cedar lighter than pine? And cheaper? If you can get that, cool.

I think it is a little more dense than pine, but not significantly. More expensive yes, but I'm not overly concerned about that investment. Like you mentioned the cheap pine doesn't seem to come in nice straight sticks, where cedar is excellent in that way, long straight grain that makes long straight boards. Actually I'll post a small section of the poem by Haida artist Bill Reid which had some influence on this thought.

Oh, the cedar tree!

If mankind in his infancy
had prayed for the perfect substance
for all material and aesthetic needs,
an indulgent god
could have provided nothing better.
Beautiful in itself,
with a magnificent flared base
tapering suddenly to a tall straight trunk
wrapped in reddish brown bark,
like a great coat of gentle fur,
gracefully sweeping boughs,
soft feathery fronds of grey-green needles.

Huge, some of these cedars,
five hundred years of slow growth,
towering from their massive bases.
The wood is soft,
but of a wonderful firmness
and, in a good tree,
so straight-grained
it will split true and clean
into forty-foot planks,
four inches thick and three feet wide,
with scarcely a knot.

Across the grain
it cuts clean and precise.
It is light in weight
and beautiful in color,
reddish brown when new,
silvery grey when old.
It is permeated with natural oils
that make it one of the longest lasting
if all woods,
even in the damp
of the Northwest Coast climate.

When steamed
it will bend without breaking.
It will make houses and boats
and boxes and cooking pots.
Its bark will make mats,
even clothing.
With a few bits of sharpened stone and antler,
some beaver teeth and a lot of time,
with later on a bit of iron,
you can build from the cedar tree
the exterior trappings
of one of the world's great cultures.

...

But what do you mean about the curves in the frame and steaming? What part of the TD? There are only rare instances when you have to steam anything, and I sure didn't. Do you mean the framing for the top of the walls?

Yeah, I was thinking that bending the proper length of 1x2 cedar to top off the walls. I suppose if that isn't 'required' maybe I will reconsider, and it might end up proving a lot more work to bend those lengths. I was also thinking, since this entire project will be downgraded from an 'all-seasons' trailer to a summer trailer, that I might install a curved window to accommodate for some night photography of the stars.

[Ira]

I was also thinking, since this entire project will be downgraded from an 'all-seasons' trailer to a summer trailer, that I might install a curved window to accommodate for some night photography of the stars.

Think about that window after you think about how big a 4 by 8 is.

It'll be easier to just go outside to take photos.

[jaeson]

It'll be easier to just go outside to take photos.

Of course

However, outside at night your lens tends to fog up (if taking long exposures), which is really bad for your photos, but more importantly your camera. So, staying inside what can be a relatively 'controlled' temperature trailer and shooting through a window would allow for long exposures of the stars.

Nonetheless I will consider it very seriously before building, perhaps I will just install a small simple window, forget the trouble of making it curved.