I’m currently working on a HO scale layout that is 5x9. I’m at the point where I would like to start putting the grass/trees/buildings in place, but I have a problem: my layout is a little strangely put together. The layout started out as a 4x8 sheet of plywood. I added a 5x1 section at the top and a 1x8 section along one side to make the layout a 5x9 layout. I would like to go ahead and make them all 1 piece instead of having them apart like they are now.
The ideas I have are to 1) just nail/screw them together 2) just buy a 5x9 sheet of plywood 3) buy 2 sheets of plywood that are 5x4-1/2 and fasten them together.
I would just make splice plates to go on the under side and glue and screw the pieces together. If you haven’t already, I would make a frame to set the wood on. 1X3 inch pine should work fine for this.
It sounds like you’re prepared to remove everything and start again. Is that the case?
Think outside the rectangle. If you’re really going to start over, have you considered an around-the-room shelf layout? (Maybe not, based on your room and “family concerns,” but it’s an option for many.)
How long is the layout going to be there? If you move, will you be able to get it out? Consider not only the physical size, but also the weight. Plywood is heavy stuff.
Finally, have you thought of using foam instead of plywood? It’s lighter and in many cases a lot easier to work with, but it’s not available everywhere.
Fairly simple spice plates should make the added plywood fairly seamless provided you pay due attention to keeping things level (shims may be needed) and not let the added section either sag or elevate. It would be in the nature of a cantilever perhaps.
However my feeling is that the basic support (legs or brackets or whatever) for the layout should be confined to the basic 4x8 and let the added one foot edge or ledge go along for the ride. It would be putting unnecessary strain on your splice plates to make the added section load bearing in other words. This could have the added advantage of creating a nice open area where visitors (and the owner) are unlikely to kick the legs during close viewing.
Keep issues of access to all parts of the layout – in particular the central part – as you think this through however. And do not forget Tony Koester’s repeated advice from Model Railroad Planning and elsewhere: yes by all means buy a 4x8 sheet of plywood but have it cut lengthwise and have a point to point that is 2 feet wide and either straight or L shaped rather than the traditional oval or figure 8 or whatever. A 5x9 does not really do much to address the inherent problems of a 4x8 other than giving you a little bit of track that is NOT curved.
Another idea is to use a doweling jig - i.e. as long as the joining pieces are the same thickness as the piece being joined.
Doweling jigs have a jaw that automatically centers the jig along the edge of the plywood. You drill your holes into the main board and insert “centers” into them. You line up joining piece with the main board so that the two pieces touch then tap the joining piece with a hammer to drive the pointed end of the center into the joining piece. (This will leave a small divot for drilling the other hole.)
For 3/4" plywood, I would use a 3/8" dowel. Place glue along the mating edges and into the holes where the dowels will be inserted. Clamp the two pieces together for 24 hours. It will give you a VERY strong joint. I made a heavy-duty changing table using nothing but dowels and it’s still working quite well.
LION used 5x9s for his original layout. Well actually, knowing the LION by now, you know that he did not buy them. They were two ping pong tables from the school that we closed in 1971. But you also need to know that larger sizes of ply wood and or paneling are certainly available, if not from a big box store, then from the local lumber yard who will be happy to special order them for you. Each sheet though is very expensive, almost twice the price of a normal sheet.
My shop teacher was doing some work for someone who required these over size panels and so in his estimate he doubled the quantity required. The homeowner asked about that, and he said it was in case he made a mistake. The home owner a bit indignant said if you make a mistake then it should be on you, not on me. The teacher said take it or leave it. A few weeks later he was back again, apparently his was still the least expensive offer that he was able to find.
Still curious to hear from the OP on weather the “table” is to be stripped and redecked or he just want to attach the sections. The type of construction and joist material and size would determine exactly the best way for solid attachment of the 12" extensions.
Sounds to be 1/2" plywood but have no idea as to what type of frame and how it’s constructed. Everyone has offered great advice, but who knows if any would work in this situation w/o further input.
I tend to agree w/ mrB that if you are to strip the ply to change it as an option, that he reconsider the overall design to a more around the wall approach. Fill us in so we can help further.