Thanks everyone for the help and input. I am weighing out the cost issue. My layout is a rather large size so I would need 3 4x8 sheets of plywood so I was deciding if I needed to go that far or just go foam. My bench is on finished concrete so I am wondering if noise becomes more or less of an issue if I bypass the ply and just go foam.
I used two inch foam board and it's working well. The foamboard is strong enough to support trains, track, and scenery. It is not strong enough to climb up on. Nor is the foam strong enough to accept any kind of fastener, everything attached to foamboard (under table switch machines!) must be stuck on with adhesives. I used both PLZ300 and plain latex caulking compound. Beware of adhesives that do not say "safe for foamboard". Solvent based adhesives like Liquid Nails are reported to dissolve foamboard.
The edges of the foam board are soft, and will dent when you lean on them. To protect the edges I made modules up from 1*4 lumber. To stiffen the modules I gave them 3/8 inch plywood bottoms, and laid the foamboard on top of the plywood. Adhesives hold the foam board in place. The bottoms give me something take the screws needed to hold switch machines, wire bundle clamps, power strips, and other stuff. Tortoise switch machines will work thru two inch foamboard, although you have to make up new operating rods from piano wire, the stock rods are not quite long enough.
I made 1/4 inch pine roadbed on my bandsaw and glued it down to foamboard. The flextrack is secured to the pine roadbed with track nails. I like the pine, it holds nails better than cork.
A table saw or radial arm saw makes fine straight and clean cuts in foamboard. You get a bit of blue or pink foamboard dust in the shop, but nothing a shop vac cannot cope with.
David Starr www.newsnorthwoods.blogspot.com
I would put the foam on to the open grid. I have not done so using caulk, but I will next time round as it will be easy to remove by just running a flat edge through it. I used PL300.
Covering a layout with sheets of plywood to mount a 3 square inch switch machines is well, what it is. You can glue a small 1/4" thick piece of ply underneath on the foam where required to mount things.
If you need to get on top of the layout, just lay a piece of plywood on top and climb up. I weigh 180Lbs and a 2' x 3' piece distributes the weight fine on 2" foam.
As far as noise goes, my track goes over many different forms of construction along the way. I have come to the conclusion that the volume does not really change, it is the frequency of the sound. Low rumbles on foam to a hissing type sound where I have the track mounted directly to cement board. And others in between. But the actual volume seems to remain quite consistent.
On a side note, I was really surprised at how much noise is created just from the wheels rolling along the track. The track was on cement so other sources of sound were pretty much removed.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
I built my small HO layout out of 1" foam over 1 x2" Grade A, 12" on center and 1x4" framing, with 1x2 grade A cross braces to keep the 12"on centers in place. I used glue and screws to be sure everything tight and stable. The goal was to be strong, stable AND lightweight. Goal accomplished.
I have had no problems with it, though I obviously do not stand or lean on it.
I use Woodland Scenics {WS} black foam roadbed over the foam base. SOme will swear by WS, others seem to hate it.
IF I havd to do it again, I might use 1/4" luan as a sub base upon which to mount the blue extruded foam base as i might in the future want to undermount switch machines and need something into which I can "bite" to mount them.
-G .
Just my thoughts, ideas, opinions and experiences. Others may vary.
HO and N Scale.
After long and careful thought, they have convinced me. I have come to the conclusion that they are right. The aliens did it.
jseese Do I need something under the foam (plywood or? and if so how thick do I need to go)
Structurally, I think you can place the foam right on the benchwork without anything under it, especially 2" foam with joists on 16" centers. A couple of things to watch out for with this:
I ended up putting 1/4" lauan between the benchwork and the foam to address both of those issues.
jseese - How to attach the foam to either the gridwork or to the plywood or underlayment (glue or screws or ?)
I used cheap latex caulk and it works like a charm. It does not need to be adhesive caulk, just plain Jane non-silicon.
Have fun!
I have been reading as much as I can and bought several books for my n scale setup. I have my benchwork done in an open gridwork. Here is the backgroud, my benchwork is 1x3's 16 inch on center supported by girder style legs. It is in a finished basement so I am not worried about warping or humidity. I have read many posts and have seen many comments on foam and underlayments but I think I am going the 2 inch foam route and cut down or add to go up. But I do I have 2 questions:
- Do I need something under the foam (plywood or? and if so how thick do I need to go)
- How to attach the foam to either the gridwork or to the plywood or underlayment (glue or screws or ?)
Thanks all,
Jon