Hello i’ m building a box frame for bench work the size is 15" x 60" with half inch thick extruded foam as the top how far apart should the cross bracing be?
Thank you
‘‘I’’ would not use 1/2 in foam without some surport under it. If you must, I would say 12in or less between cross pieces
What about 1 inch thick foam?
My impression is that most people use 2" foam if they are not going to lay it on plywood. 1" is still pushing the envelope. My local Home Depot had partial sheets of 1/8" ply in the cut wood box they let me have for free. 2" foam gives you some depth to cut gullies or creeks.
Cross bracing has a tendency to be right where you want to mount switch motors so bear that in mind.
1in isn’t all that mutch better, I have some but 1/8 ply under it.And it still isn’t as sold as the 2in. without anything under. If you could see your way clear to go with 2in, you’’ could’’ run the complete15x60 without any cross members.I’ve spanded 24in with 2in no problems
You can use gussets with or in place of cross bracing. If you use cross bracing keep in mind that you will need access under the layout and or to use that space for storage later. There’s an old sying that the layout takes up space but then gives it back.
Good luck
Bob
Half inch is too thin, even with cross bracing.
What ever your decision is, drill two or three 1" holes in the cross bracing before you install them. That will make it easier to run wires. Drilling the holes before installing the braces is much easier than after they are installed.
One inch extruded foam will be nice 'n stable with supports spaced ever 12" below it. If you place a heavy object between those supports, you can expect a bit of sag, but what that might be, except for an 18 volt cordless driver, is beyond me. Your locomotives won’t budge it unless you are in O scale.
You can get 1.5" extruded foam. That’s what I used ten years ago in my only such construction. It was solid, but I laminated it below with 5/8" ply G1S and had monstrous 2X4 legs supporting the entire thing. Much too much. Didn’t know what the aitch I was doing.
Feel safe with 1" foam, but only the extruded insulation board, not the sheeting packed around dishwashers NIB. Use 12" spacing below it, and as Big Daddy cautions, think ahead. Choose your supporting structures’ locations carefully.
Hi,
In my opinion, the use of foam as a layout base by itself is the beginning of a whole lot of problems. But if one must use foam, at least have a 1/2 inch ply underlayment. And, have that ply underlayment adequately supported by spaced risers - say one or two foot squares.
If You are using that for a shelf… 3 length’s of 60’’ 1x2’s on edge, one on each side, one down the middle. Two length’s of 15’’ on each end edge and one cut to fit in the center of the long 60’’ pieces, all glued and screwed, with Your foam glued to the top…it will be extremely strong, with a minimum of four shelf brackets for support. Just a suggestion! I’ve done it before…
Take Care! [:D]
Frank
As others stated, 2" foam is a perfect base for a sub-roadbed. Foam less thick doesn’t provide much support or flexibility for waterbodies, gullies, etc. Such features are quite easy to make when you have so much depth.
For spaces for braces, I have 1x4s every two feet. This provides plenty of durability supported by 2x4s for legs.
LION Recommemnds 16" Centers for such tables. You need those extra 4" to get a drill in between the peices. Holes are just so nice!
LION used 16" centers and used 1/2" thick celotex as the only surface. Of course this sort of Celotex is no longer available. It has something to do with fire codes. People use sheet rock instead of this stuff in their buildings. Can’t say I blame them. That is why we pulled the stuff out and so had 10 sheets of the stuff in storage, just waiting for me to put it on my train layout.
LION has some 3/4" foam surface on 16" centers without extra support. LION would therefore recommend 1" foam as a simple or minimum standard for such tables, with a 16" support centers.
But them maybe LIONS are just not so fussy. Him really likes 2" thick fiberglass boards, the kind with tar paper on both sides. I just use peices of foam to hold them up.
ROAR