Which type of wood to use for benchwork for a portable layout?

[mager]

Hello everyone, I plan to build a layout very similar to the Beer Line which was published in MR in '09. I want a light weight layout because I plan to be able to move it if necessary. What type of wood do you experts recommend for the frame of the benchwork with considerations to cost, strenght, expansion due to humidiy, and most importantly weight?

Thanks for your input.

[Iron Horseman]

Hello everyone, I plan to build a layout very similar to the Beer Line which was published in MR in '09. I want a light weight layout because I plan to be able to move it if necessary. What type of wood do you experts recommend for the frame of the benchwork with considerations to cost, strenght, expansion due to humidiy, and most importantly weight?

If you are really concerned about strength, weight, and humidity aluminum might be a better choice than wood. For strength, cost, and heat I would consider cutting 3/4" plywood for the benchwork framing. For a compromise on all the factors you mention good old #1 pine 1x4's is hard to beat.

The weight will really come in from the surface not the frame. If you overlay everything with heavy plywood it will get weighty really quick. All of my modulars are made with 1x6 frames and 2" foam surfaces. Another big weight factor is the scenery. Plaster and real sand add the pounds quickly. I switched from real sand to Woodland Scenic's "gravel".

My latest modular is a corner. It is 4'x6.5'. #2 pine & foam construction. Weighs about 14 lbs.
[img width="150" height="200"]http://www.walkersquawker.net/images/modular_corner.JPG[/img]

[Selector]

An open frame with one or two joists would be fine if you use clear spruce or pine 1X4. Obviously, be picky and select non-warped stock that has not been left in humid conditions that might possibly warp as it dries a bit. I let mine sit in a humidity-controlled basement for at least four days, usually a full week, and I don't stack it or weight it. I want to see what it does as it dries unfettered.

I would use 1X2 spruce, fire, or pine for stilt legs in each corner with wood piece blocking around the top but end, tightly driven in with wood screws to form a chamber into which the tops of the stilts can be forced.

The same 1X2 can be used for diagonal bracing for each stilt to keep them from breaking.

[mager]

With using foam as the top board, is there a concern that too much wieght from the seanery, (or a poorly placed hand for support) might go through the foam?

Thanks for your inputs.

[Beachbum]

In previous layouts, I used 2-inch foam with minimal support and had no problem with anything breaking through it or bowing it. 1/2-inch might be a different story.

[Selector]

With using foam as the top board, is there a concern that too much wieght from the seanery, (or a poorly placed hand for support) might go through the foam?

Thanks for your inputs.

As stated above, 1.5" and thicker foam are fairly strong. However, it can be significantly marred if not protected at its borders, so it should be inset into the frame as much as possible. That's why I said 'open' frame. The 1X2 joist or two below it will help to support it from anything but a determined knee or serious and regrettable accident.

You could place 1/4" plywood between the joists and the bottom surface of the foam for even more protection, but you will be adding about four pounds to the whole.

[zoegraf]

There are some demos on youtube I was looking at last night that are quite interesting. So many options.

[waltr]

Read this article:
http://www.railwayeng.com/Newloop/index.htm

To have a light weight stiff module keep the amount of material to a minimum. Read up on aircraft structures for ideas.
Another method is to use thin panels sandwiched over a very light weight core (foam, honey comb, etc). One of my favorite materials for panels is 1/4" Luan. With a foam backing or just light pine 1x2's a stiff light weight structure can be built.

[Gene Kruger]

What size/dimensions are you thinking about????

[mager]

I will copy the Beer Line project layout in terms of frame dimensions. 2 sections of 2'x4' and 2 sections of 2'x8'.