Base-board suggestions please

[BrianTJohnston]

Starting sometime in the New Year I hope to make a start on my 1:250 harbour diorama. I am envisaging something in the region of 2x4 feet (600x1200mm) and am wondering about what to use as a baseboard that will be rigid enough but not too heavy for ease of handling.

At present my mind is working along the lines of the rigid blue foamboard that you see being used as insulation in timber-framed buildings. I think the slabs are about the right size and about 2 inches (50mm) thick.

Any other suggestions would be welcome.

Thank you everyone,

Brian

[Tapcho]

My choice would be somekind of wooden worktop material sawed to your custom size. It will not twist, it takes paint and glues well and offers a solid base to build on. It's heavier than the foamboard you are thinking and I suggest you use the blue foamboard on top it for your landscaping needs. This is my plan anyway.

Tappi

[SCEtoAUX]

Hardboard would be a nice rigid underlayment that is not too heavy. That is the stuff used in making some clipboards. :)

[Petrina]

Have you ruled out balsa wood?- it sure is lightweight.

[Zathros]

Personally, I would consider a thin veneer, and then make a frame underneath, This could allow for under water type objects to project, or full hull ships to be cut into the veneer. It would also be easier to texture a thin veneer for effect and then mount it to a frame made out of wood, or metal, for rigidity. You could theoretically use a translucent material and make something really different and watery looking.

[dell_zantoz]

How about a bulletin corkboard. The ones in the office that you pin memos and stuff. They are rigid and lightweight. You might need to seal the section that you want to use first. Something like this..Universal Cork Bulletin Board, 36 x 24, Natural, Oak Frame - UNV43603 (http://www.discountofficeitems.com/office-supplies/boards-easels/boards/cork-fabric-bulletin-boards/universal-cork-bulletin-board-natural-frame/p51621.html?ref=nextag&source=nextag&utm_medium=shopping_engine&utm_source=nextag)

[RickTNRebel]

I'd go with 1/8" inch luan plywood surface with a torsion box base made of the same material. Cheap, extremely strong and light weight. A decorative frame could cover the outside if needed. You can run wiring or display supports (screws, wires, etc) underneath, out of view.

[Retired_for_now]

harbour diorama
2x4 feet (600x1200mm)
rigid enough but not too heavy for ease of handling.

Simple and rigid could be done with mdf (medium density fiberboard - basically glue and sawdust rolled into flat sheets) probably 1/2 inch thick would be enough. At that size almost anything will be heavy and awkward so you should make it up in sections sized to either the diorama elements (break points in the base at the edges of diorama elements) or your method of transport (so it fits in the trunk of the car). The sections can be just set next to each other or you can dowel the edges (like a sectional table top).

Check a few model railroad sites or blogs and see how they are doing it.

Yogi

[Don Boose]

I think it depends on how you are going to use the diorama. Foam core is light and transportable. Fiber board and wood are sturdier but heavier.

I have been thinking of foam core, too. An egg-crate type framework would prevent warping, I think. I have such a board in mind for my entry in the Sealand Express group build.


I have also been thinking of matt board with an egg-crate underframe.

Don

[Retired_for_now]

Lots of good ideas on foam core, egg-crate, or honeycomb type construction with a veneer. The hard part is getting the top (visible) area to join cleanly if you don't make a one piece display (which is hard to handle or move).
Professor Lucifer Gorgonzola Butts recommends building a flat, stiff support using one of the light weight ideas (in multiple sections if needed) and rolling out your finished diorama surface (no seams) on that. The diorama elements then get set on or plugged into the surface.
Yogi (simplicate and add lightness ... never!)

[Darwin]

I agree with Don on using foam-core posterboard. I have had good results using it on diorama bases (although not as big as the one you are proposing). I'd try making the support grid with three-inch centers beteen the stiffener strips, and maybe using wood lath on every fourth stiffener. It might be overkill, but on something that large I would put a foamcore bottom on it as well as the top...kind of like making a hollow-core door. You might pick up a few other ideas by reading some articles on making a modular N-scale railroad layout.

[cdavenport]

Here is your answer...having done this on many occasions.

Simple and LIGHT were the design requirements. Your use of foamcore is an excellent start. To make it rigid, obtain some cardboard (USPS shipping boxes are excellent material and free for the asking.....another equally suitable option is the box in which a computer is packed). Cut the cardboard into strips, perhaps 1 to 2 inches in width. Assemble them into a grid on the bottom of the foam core. Elmers white will stick nicely to foam core, but Gorilla Glue is incredible for its strength and rigidity. Likewise, two-part epoxy works like a dream. But, the latter two are kind of expensive.

Think egg crate with your base glued to it. In that fashion, glue your cardboard first to the perimeter. Then, glue, perhaps, two strips equally spaced along the long dimension. Across the short dimension, glue, perhaps, three or four strips. Make sure you measure the strips so that they butt against each other, adding glue to strengthen the butt joint.

You can go through the drill of making dovetail cuts so that the strips actually link together, but it's a waste of time. The glue will make butt joints as rigid as you need them.

While you are doing this assembly/gluing, I recommend that you place the foam core on a flat surface such as the floor and weight it down so that it does not cup as the glue dries. It's also a good idea to place a weighted cover on the strips as they dry.

Once the assembly dries, it will be rigid, strong, and very light. The whole process, including the cutting of the strips should take a couple of hours. Let the assembly dry overnight.