I have almost completed my new benchwork. which is around the walls with 1/2 inch plywood base. My question is should I lay foam ins. on top or not, if so what thickness is better if any? My big box stores seem to only carry 1/2 inch. I plan on using the ws risers and inclines and maybe scrap foam for mtns. and topography. Thanks for your inputs Dave
I've been very pleased with 1" thick foam on plywood. It's not so thick that I have issues trying to get under-the-table switch machines to work, but still allows me to do some "below-grade" sculpting. :)
My layout uses thin foam (fan-fold underlayment) in place of cork or other roadbed material, over either cookie-cut plywood or the inside of steel studs laid rain gutter fashion (on hidden track only.) The foam, and the track, are anchored with latex caulk. The result is a very quiet railroad - much quieter than cork on plywood, or anything on thick foam without plywood. Even the steel studs are quiet - and I was expecting them to be noisy!
That thin foam is definitely useful, as a noise reducer if nothing else.
Chuck (Modeling Central Japan in September, 1964)
My layout is 2-inch foam, with no plywood. It's a 5x12 foot table layout on wheels, so light weight is a consideration to me. You don't have the weight issue.
The foam does allow you to easily carve down to get ditches, gullies and other low areas. Scrap foam is nice for building up. I'm one of those who does not like flat spaces. If I've got a few tracks 3 inches apart, I'll either dig down or build up to give my terrain some more interest in between them.
It takes an iron man to play with a toy iron horse.
Thanks for all your suggestions. I think I will go with the foam over plywood. I also dont like all flat terrain. That was one of my many mistakes on my first layout that was just dismantled a while back. Dave
misterbeasley, how silly of me to suggest a mechanic's creeper with an incline on it to help you do wiring. Just get yourself a reclining beach chair and pull your layout over you. That way you're much less likely to spill your drink. What is the spacing of the ribs under your foam, and what are they (1 x 4, 1 x 3.)
Dave, I used 2 inch foam on top of 3/4 plywood. I all so used latex chalk to hold it down. Just set something heavy of the foam while the chalk sets up. Over all I am pretty happy with the 2 inch, but if I had a do over I would go 3 inch or make drop down section of the wood frame it self for a bridge.
Only 1/2 foam at you LHWS? You must be in a warm climate, here in the Midwest I have seen 4 inch. Little tip on buying the foam, at Home Depot when I find a damaged pieces, I ask for the department head and ask for a discount. I normally get 75% off, turns a $25.00 2 inch section in to a $6.25 section.
Cuda Ken
I hate Rust
Thanks Ken, you are right I live in S.C. and I have only found one HD with a couple of sheets of 2 in. foam. May have to try to stack the 1 in. I do want to have some bridges. Thanks again. Dave
Ken,
I never thought of trying to get a discount on damaged pieces of foam. How damaged do they have to be to qualify for the discount at your local Home Depot? I've seen pieces of 2" foam at my local Lowes that have damage to their edges, but nothing very serious Next time I'm in the market for foam board, I'll look for damaged pieces and see it they'd give me a discount.
Bob
Bob, I have got discounts where just the edge is bent a little or a small section of a corner is missing. But, the more mangled it is the better discount you can get. Onces they get to know you, they may start holding the damaged foam like they do for me. Heck, Bob calls when there is some messed up foam.
Alright, Cuda! So YOU'RE the guy who's been getting all the 2" foam around here!!!!! I wondered why I could never find any damaged sheets!! LOL
Darrell, quiet...for now
bob@osd misterbeasley, how silly of me to suggest a mechanic's creeper with an incline on it to help you do wiring. Just get yourself a reclining beach chair and pull your layout over you. That way you're much less likely to spill your drink. What is the spacing of the ribs under your foam, and what are they (1 x 4, 1 x 3.)
Here's a shot of my benchwork, before any foam went on it:
The legs are 2x3, with triagular gussets made of 3/4 inch plywood holding the legs to the frame. The outer frame is 1x4, and the rafters going across are 1x3. I set the bottom of the rafter even with the bottom of the outer frame, so the foam sits down 1 inch inside the frame. This protects it, and gives me room to add a fascia later.
My layout height was set to allow it to tuck underneath the 45-degree roofline. It works out pretty well for reaching over, too. At 5 feet wide, the center of the layout is therefore at the recommended maximum "reach length" of 30 inches. It's awkward at times, but workable. On the other hand, this height is really not very good for doing under-table wiring. It's too low to kneel, and too high to sit. Maybe sitting on a beach chair is exactly what I need. I'll give that a try - I think we've got a couple of K-mart specials in the garage. They're old, though, so they don't have "beverage" containers. (That would be really handy for holding tools, wouldn't it?)
I understand you have made up your mind, and the question is really moot. But...
Unless you truly prefer foam scenery to plaster or some similar scenery shell, there is no real reason to cover adequately supported 1/2" plywood with foam. The plywood (assuming supports at 16-18" intervals) has plenty of strength.
What I do sense from your description is that you are not planning on using the cookie cutter technique to reduce the flat areas to under the track, and places where structures are going to go. The traditional cookie cutter plywood on risers and plaster shell scenery combination actually works very well at producing smooth grades and scenery both above and below grade at relatively low cost.
The primary benefits of using foam are much lighter weight (which has been pretty negated by the 1/2" plywood in this case) and the ability to carve scenery with a knife or hotwire cutter (a personal preference). The drawbacks of foam are added expense, added thickness to the roadbed sandwich, and a different kind of mess in producing scenery. Smooth grades with foam typically involves paying for and carefully installing WS risers (there are other more labor intensive methods). If using a glued plywood/foam sandwich, 1/4" plywood or even no plywood is sufficient.
my thoughts, your choices
Fred W
Tips for finding extruded foam in mild-winter areas
Layout Design GalleryLayout Design Special Interest Group
Thanks Fred for your input. No its not etched in stone yet about the foam over plywood. I just want to be able to create an uneven topography where needed and to be able to have bridges and different track levels. My last laypout was primarily flat. I have worked some with plaster and cardboard strips. Thanks again Dave
I just wanted to add my two cents. I did not use foam on my 1st layout and after I had all the track laid down I realized that my river was to high. I managed to cut the plywood from below and drop the river, but this time around I'm putting in 2" foam.
JohnnyB
Another thing to consider is your switch machines.
Tortoise slow-motion machines are designed to mount beneath the table, and need a solid base. This doesn't work well with just foam. Some people end up gluing a piece of thin plywood below each turnout to mount the Tortoise on, and they use a long throw shaft up from the Tortoise.
At the other end of the realism-vs-price curve is the Atlas machine, which normally mounts above the table and, IMHO, doesn't look very good. Atlas makes an under-table mount machine, but the throw shaft is only about an inch long, meaning 3/4 inch plywood and 1/4 inch roadbed is all you get. People haven't had much luck using home-made longer shafts.
The Peco twin-coil machine mounts directly to the underside of a Peco turnout. (It won't work with other turnouts, because it needs the spring that is unique to Peco to hold the points in place after they're thrown.) Here, you need to cut out a decent-sized slot for the machine to fit down into. This is easier to do with foam.
You'd be suprised, MisterBeasley. I did all mine fromt he top with littel squares of perfboard, but as a test I tried just glueing one right to the bottom with some caulk - and there was no way it was going to shift once the caulk dried. It took a lot of effort to remove it. So this time around, they are going right on the foam, from underneath. There will be 4" of foam this time, so the mechanism will operate via a wire in tube type of arrangement rather than just having the arm wiggle back and forth. But I see no need to fasten the Tortoise to a piece of wood before attaching it to the foam, it definitely will NOT shift position or fall off.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I don't have any Tortoises myself, just repeating what others have said. That's good info, though. Thanks.
This is definitely helpful. My layout is constructed of 2" extruded foam on a grid of 1x4s. I love the light weight but I have been worrying about switch machine mounting. One suggestion was to put a 4" by 4" sheet of thin masonite directly under the turnout, gouging out a 4x4 square the thickness of the masonite. Then cut out a hold in the center of the square big enough for the switch machine to fit into. I know this seems like a lot of work, but I had heard that glue wouldn't hold anything against the bottom of the foam. It certainly makes life easier to mount a piece of plywood or masonite under the foam and attach the switch machine to that. I will definitely give it a try.
Russ Norris
I have tried methods suggested here for mounting switch machines before settling on mounting everything on sheet styrene. Although have chosen to use Atlas under table machines, I also used the same technique with Tortoise machines. At my workbench I assemble both turnout and switch machine on sheet styrene and then drop the whole assembly in place on top of the foam. There are photos and a description of this method in an on-line photo album. I like this method because I don't have to crawl under the layout to make mechanical connections. Further, the turnout and switch machine can be removed for servicing or replacement with a minimum of fuss.
http://www.augustastationmaster.com/foam_steel_construct/index.album/installed-turnout?i=21
This album also illustrates how I build benchwork with 2" foam and steel studs - no plywood needed. Rather than cutting into this foam base and compromising it's strength, I recommend using Woodland Scenic foam risers or other foam to raise the track above the 2" base to permit scenic features below track level.
Jerry Smith
I agree with the others, 2" of foam gives adequate support for track and everything. I generally provide some support every two feet although there are areas where I have gone three feet without any support or problems. I gave up on plywood the last time it took 4 men to get my 4x8 layout out of the basement. Now, I have 2" foam laid on 3" wide, 3/4" plywood supports. The 3" wide support is mounted so the 3" section is in the vertical and is extremely strong. This is then supported on 2x2s legs. I made sure all pieces are modular so that the next time I move, they will fit within 27" door jams, either horizonantly or vertically. By the way, construction polar foam works pretty good too. It has foil on one side and cuts nicely with a hot knife. The foil allows you to hot glue pieces together without melting through the foam. It is cheaper than the blue or pink stuff. Doesn't carve as nicely though.
One gentleman suggest styrene sheet plastic for switch machines. I had explored that idea looking for something that was reasonably priced, the same thickness as the foam or cork roadbed. My solution was the modelers plywood, 3/16" thick. Two types are available, model aircraft or hobbyist. The aircraft is more impervious to liquids, etc but I get the cheaper hobbyist ones and taper the sides on a sander. Then I spray it with the tan camoflage paint available at just about anywhere. This allows me to ballast and wet the turnout area without warpage. I then can mount my tortoise machines with short screws to the bottom and generally prepare my whole switch on the bench, including wiring. I can also screw or tack in my operating switch stands to the plywood easily. With a 9v wall wart at my bench, I can test operate and adjust everything at the comfort of my bench.
I then use my Hot Knife to cut out the foam for the switch machine and wiring. Quick and easy, a reasonalbly priced solution and no great stress on my old back. I found styrene and several other similar thickness materials too flexible or messy after with my ballasting efforts with water.
I also use latex now for mounting the plywood switch machine assembly, track and roadbed. I like it because it stays in place and yet is removable without destroying everthing.
Just my 2-1/2 cents worth.
One club's portable layout using 2" blue Styrofoam in a 4 foot wood frame finds it is 1/4" shorter than five years ago. That's only about 2% and might be unnoticeable for scenery, but is with track on it. It might not occur if the foam is glued to plywood. Has anybody else had problems with Styrofoam shrinking?
Ian McIntosh One club's portable layout using 2" blue Styrofoam in a 4 foot wood frame finds it is 1/4" shorter than five years ago. That's only about 2% and might be unnoticeable for scenery, but is with track on it. It might not occur if the foam is glued to plywood. Has anybody else had problems with Styrofoam shrinking?
Ian:
I have a 24x24' garage layout that is built with 2" styrofoam (Corning) on a 1x4" open grid, and I've had it for seven years and have had no shrinking of the foam base whatsoever. I glued the foam to the base with Elmer's Carpenter glue, over cross-supports every 12" or so. The layout itself extends from 45" at 0 track elevation, to over 72" at the highest track elevation, and even in a garage that is only partially insulated, there has been no problem with shrinkage.
It could partially be because I made the cross-support grids only 12" apart, instead of the usual 24" that I would have used with a plywood base. But the styrofoam is securely glued to the grid. However the layout is both lightweight and sturdy, and being a mountain layout, has several track levels, which the foam supports very well.
Here's a photo of a portion of it, if this helps: The entire layout is built on foam risers.
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
Hey Dave.....For my layout, I have similar benchwork with 1/2" plywood for the tops. Living in Texas, you can't get foam that is of a decent thickness. Home Despot has 1/2" only, and Lowes has 1/2 " and 3/4". I used two layers of 3/4" on top of the plywood. Foam is cheaper than plywood, and if you change plans, and you probably will at some point, the plywood that has had cork glued to it is no longer usable. So, I use the foam so that I don't need to replace the plywood, in addition to the other benefits of using foam of coarse. If you glue several sheets of foam together to build up the thickness, keep in mind that what ever you use, be it glue, calk etc., it will take a very long time to dry in the middle areas. Most of these adhesives require exposure to the air to cure. I have used Elmers glue and adhesive calk with equal success, but when cutting into the foam several months later, found that the adhesive still had not dried completly. Also, to attach the foam to the plywood, I am now just attaching it with sheet rock screws though the foam into the plywood, then I cover the hole with a piece of masking tape, so that the head of the screw stays clean for future removal if needed. Hope this info helps.