I'm going to build a shelf layout in a bookcase. The dimensions of the shelf cavity are 78" x 15" x 12" high. I would like to minimize the base height - I was hoping 1" high. I would like the base to be lightweight so I can remove it for workbench work.
I was thinking of using 1/8" lauan plywood for the top, framing with 1" x 1/2" lengths of wood under the edges and sides. I would use triangular pieces of 3/4" wood in the corners for extra bracing. All glued and screwed.
I was thinking making the top with lauan could help with the weight; it was used in an April 20i9 MR article about lightweight benchwork.
I only have basic woodworking tools, but I figure I can have the wood cut at the lumber place, though I'm sure I could cut the framing and triangular pieces if necessary.
I'm hoping this would provide a pretty rigid base. Any thoughts or advice?
My thought is that what this really comes down to is how much will a 78" long piece of 1x1/2 flex with the weight of the materials on it when you need to transport the layout to a workbench. Assuming lightweight scenery (i.e. not making a slice of the rockies out of plaster), given the weight of what could stay on the layout while you move it, I would guess it would be fine. I would be sure to have plenty of cross members to the frame for you to fasten (and I would glue as well) the lauan down so that it doesn't warp in the middle over time. Triangular pieces in the corners would not be necessary. The luaun will hold the frame square.
Mike
I have built a number of layouts to take to exhibitions here in the UK.
One of the problems with larger boards is moving them!
While moving a basic piece of wood 78" long around is OK, what happens when it is covered in delicate scenery, buildings, track and with wiring underneath that is guaranteed to snag on something>
I would suggest making a couple of boards that can be managed and manipulated when needed.
There are plenty of techniques to cross a baseboard joint with track, electrics and scenery.
Trevor
For my around-the-walls layout I'm using shelving from Menard's - I believe the maker is John Sterling. It comes in a variety of sizes; in your situation the 72" by 15-1/2" size would be closest, or you could use two of the 36" long ones (or get one 36" and one 48" and cut the 48" down so together they come out to 78". They're only about 1/2" thick, but very strong and seem to not want to bend or warp at all. I usually use the white ones, since I'm going to put scenery over them.
I think your basic plan is sound, but a few thoughts:
1 - as others have mentioned, the 78" length may give you problems when moving. Two 39" halves would be a lot better. If you build precisely, you should have no need to physically connect the base halves or the track (only electrically - see #2). But building precisely will require making the cuts yourself - store cuts are going to be +/- 1/16" (if you're lucky), and not precisely square. You can buy a reasonably good power mitre saw at the big box stores for under $150. Not professional grade, for sure, but with practice and care, it will do the job for you. I sold mine locally for about half what I paid for it after I was done with it.
2 - Suggest you up the framing lumber to 1x2, which is actually 3/4x1-1/2. Use the taller dimension as the height, (just a little taller than you had hoped), and drill at least 1/2" diameter holes for wiring to pass thru all interior framing peices before assembly. Use #1 pine, and pick and choose the nicer peices at the store. Connect the 2 halves electrically using an automotive trailer plug.
3 - I would agree, the triangle gussets would not be necessary.
Sounds like a fun project - we're here to help as you go!
Ed
I would make a box (frame) out of 1" aluminium angle or channel stock and put a piece of 1" foam in it. Very lightweight.
I did something similar using iron and cement board for my fireplace crossing. You want quiet running, use cement board.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."