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pros and cons of plywood or foam base

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pros and cons of plywood or foam base
Posted by gnsoo on Sunday, April 17, 2011 2:58 PM

I have built a few layouts with a plywood base and plan on building a new layout after I move to a different house.  I was wondering the pros and cons of either foam or plywood base, track laying, switch machines, wiring, scenery, running noise ect.

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Posted by Hamltnblue on Sunday, April 17, 2011 4:07 PM

Welcome to the forums Welcome

I always believe in using both. Plywood on bottom with 2 inches of foam on top.

Springfield PA

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Posted by gandydancer19 on Sunday, April 17, 2011 5:18 PM

On my present layout, I am using one inch foam on a Luan surface.  I think it is noisier than 3/4 inch plywood, but going below grade is sooo much easier.  It also makes mounting switch machines on the bottom easier.

Elmer.

The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.

(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.

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Posted by cowman on Sunday, April 17, 2011 7:54 PM

Welcome to the forums.

With foam there is no expansion and conrtaction or swelling in hot/cold, dry/damp weather.  It is ightweight, easy to handle and cut, but keep a can of anti-static spray and a shop vac handy if you cut it with any kind of a saw.  Repairing a place where you took out too much is easy, glue in a new piece.

Foam can dent if you don't protect the edges, but most folks put a facia of some sort on their layout anyhow.

If you are going to have grades on the layout plywood is good for cutting cookie cutter style.  WS inclines have helped making grades on foam easier, but there is a cost.

For portable modules, I would use a piece of 1/4" luan or plywood under the lightweight foam, just to protect the bottom during moving.   On a perminant layout I have seen articles where just a strap glued under the foam at each support location is used.

There are many pros and cons to both.  I'm sure you will get many comments.  Look them all over and see what suits your situation best. 

Good luck,

Richard

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Posted by chochowillie on Sunday, April 17, 2011 7:58 PM

Embarrassed So what is  Luen???

Cho Cho

CDN Dennis 

Modeling the HO scale something or other RR in the shadow of the Canadian Rockies Alberta, Canada

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Posted by larak on Sunday, April 17, 2011 8:34 PM

@cho cho:  Luan is a type of plywood.

One thing not mentioned above is that you probably don't want to kneel on foam. I use 2" or 1" foam glued on top if 3/8 plywood, even with cookie cutter. Works great, allows carving below the surface and is very strong.

 

The mind is like a parachute. It works better when it's open.  www.stremy.net

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Posted by KHM60 on Sunday, April 17, 2011 8:38 PM

same thing as luan but with an e

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Posted by gregc on Sunday, April 17, 2011 8:40 PM

chochowillie
So what is  Luen???

Luan is a higher quality ($$) 1/4 plywood often used to make interior doors.   do a web search and check it out next time you're in a store that sell lumber.

greg - Philadelphia & Reading / Reading

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Posted by dehusman on Sunday, April 17, 2011 9:43 PM

Depends on the layout you are building.  If you are building a basically flat layout with some small areas below grade, flex or sectional track minimal grades if any and surface mounted switch throws or machines then foam is probably pretty good.

If you have lots of changes in elevation, want larger valleys and peaks, use under the roadbed swith contols or linkages or are handlying tracks, then plywood is the way to go.

I have built one layout for my son that was layers of 1 and 2" foam on a 1/4" plywood base and hopefully will never have to build one like that again.

Dave H. Painted side goes up. My website : wnbranch.com

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Posted by Medina1128 on Monday, April 18, 2011 9:00 AM

On one of my modules, I used a base of 1/2 plywood, then stacked foam on top of that. If you're going to have a flat layout, then use foam to build your layout up from that base, that's fine. If, however, you're going to stack foam and put you're track on top of that, I'd advise against it. I found that wiring the track became a major pain to drill holes in the wood base to feed the wires through. I ended up drilling holes with a 2 1/2" hole saw. For my next modules, I build a frame of using 1x4, then glued the foam to top of the frame. At that time I used Liquid Nails for projects, but have since changed to using acrylic latex caulk. I have one section that's 12" thick. I made a tool out of a wire hanger to feed the wire through the foam. It has a hole at the top and the wire is fed through the foam like a sewing needle.

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Posted by vsmith on Monday, April 18, 2011 11:01 AM

I used a 1/2" plywood base over 1x framing because I had to be able to sit ontop of the layout to lay down track at the rear of the layout against the backdrop, that something to consider if its a big layout. You then work outword from the backdrop to the front laying foam and scenery and such.

   Have fun with your trains

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Posted by BATMAN on Monday, April 18, 2011 11:49 AM

I will tell you why I did mine the way i did as I a firm believer in the "there's more than one way to build a MRR" camp.

I used 2" foam over 1" x 4" open grid bench work. The reasons for this are I always wanted to try this method after all the "Plywood Pacific's" of the past. It is very easy to put in a stream, culvert or Hwy under pass, by just cutting into the foam. Foam is very easy to repair if a spot is damaged or not to your liking as far as landscape contour is concerned.

Your layout can be portable, movable or built in. I wanted my layout to be movable. The long part you see in the photo is 18' x 6'. Two of us picked it up and carried it around and into the house from the garage where I had built it. Foam is very lightweight.

One thing I will never ever do again is put foam over plywood. I have a small 4' x 4' spot on this layout that has foam over plywood and it drives me nuts. Working through plywood is easy and working through foam is easy, but working through foam and plywood together, I found myself grrrrring a lot.

When you consider the weight we put on top of the benchwork is measured in ounces or a few pounds at best, 2" of foam without plywood is more than addiquit for the job.I have climbed on top of my benchwork by putting down a 2' x 3' piece of plywood to kneel on. there was little evidence I was there when I got off. I have built a lot of things in my 54 years and often use to overbuild things. I have now learned that overbuilding is a waste of money and can often be counter productive.  By not using plywood you save money, and the less wood on a layout the better as far as having to worry about warping etc. I am a big fan of steel studs. Steel studs and foam are the perfect combination and steel studs are cheap and easy to work with.

As far as risers are concerned, I built mine out of spline, again just because I wanted to try it. Just Google "Spline Roadbed" in images and a million "how to" pages come up. I have 80' or so of spline roadbed for about $16.00. Spline transitions in and out of grade and curves beautifully and in a very natural way. In the photo below you can see the climb from the foreground to the apex, midpoint of the window. The maximum grade is 2% however it undulates along the way between 0% and 2%. My longer trains look really neat climbing that hill because of that.

I am not sure how much 80' of WS foam risers would cost but I bet spline is a lot cheaper. As far as plywood risers go, I personally never liked that method. Cookie cutting plywood I find somewhat wasteful and I was never happy with the transitions in and out of grades. Spline roadbed has very little if any waste.

I think the questions to ask yourself are is the layout portable,movable or permanent? How big and what shape is the layout? How much can I or do I want to spend on different things. Answering these questions and maybe a few others will help you decide on how to proceed.

Don't forget to keep asking questions. The people on here are great at helping out.Smile

 

 

                                                             Brent

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by mobilman44 on Monday, April 18, 2011 12:23 PM

Hi!  And welcome to the Forums!

For me, plywood is the only way to go for a model railroad base.  The foam stuff may be great for carving mountains or other scenery attributes, and may even work ok as a roadbed or scenery base.  But, to support something as delicate and complicated as a layout, you really should have something solid under it.

 

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central 

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Posted by HHPATH56 on Monday, April 18, 2011 12:55 PM
On my24'x24' HO layout there are six inch deep harbors and rivers and 2ft. high mountains, so I used 5/8" plywood and cut out the shape of the rivers and harbors, and buit up reinforced arc mountains (to span five tracks). I mark and cut out thee rectangular holes for mounting 96 under layout switch motors. Bob Hahn
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Posted by bogp40 on Monday, April 18, 2011 1:10 PM

Even if you are building the layout prodominatly of foam, I would recommend using at least 1/4" ply as a base for the foam. Laun underlayment is relatively cheap. This isn't so much for any strength issue but the use of the plywood will prove helpful for all sw machine mounting and any other mounting of buss wiring, etc.

There are a few different qualities of the Luan, the cheap soft core stuff @ HD and Loew's is rather weak as compared to the better grades found at a "real" lumber yard. The junk "stuff", you can snap a corner off w/ bare hands, won't happen w/ the better plys on the good stuff. I work w/ all sorts/ grades of ply on a daily basis, there is a difference.  If you want a better base, not that it would probably matter under all that foam, look into the Doug fir PTS/ underlay plys in 1/4, up to 1/2" Building a cabinet benchwork then go for the Baltic Birch!!! Ya right.....LOL

Modeling B&O- Chessie  Bob K.  www.ssmrc.org

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Posted by tgindy on Monday, April 18, 2011 6:01 PM

Most of the responses have included some type of plywood as a base, or to attach turnout machines, under benchwork wiring, etc.

In all cases, the plywood only, foam only, or combination of plywood + foam has been used to more effectively suit specific needs of the layout for the model railroader.  Foam, plaster, or ground goop can effectively be carved and/or built up for scenery.

CR&T must use plywood for support-strength for traction poles and its live overhead as a traction layout, and; foam will be used to build up scenery.

If you have access to How to Model Realistic Layouts: Trackside town & city scenery -- Tony Koester on page 35 in "Figure 6 Modeling Metcalf -- includes a construction photo where the scenery is flatter with some gently rolling hills...

...and here's the caption:  "With most of the NKP and B&O track at Metcalf in place on Tony's layout, he is now installing the streets and structures,  The main line is elevated 1/2" on Homabed to allow for ballast, ditches, and land contours."  P.S.:  The layout base is plywood, and the track is 1/2" above the plywood.

Conemaugh Road & Traction circa 1956

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Posted by chochowillie on Monday, April 18, 2011 6:21 PM

Ok, gotcha. Sort of like Baltic Birch plywood from Russia with 2 times the lamination than normal 1/8 inch we normally get in North America.

Chu Chu

CDN Dennis 

Modeling the HO scale something or other RR in the shadow of the Canadian Rockies Alberta, Canada

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Posted by jarnett on Wednesday, April 20, 2011 10:38 AM

I enjoyed your post, as I am about to put together a smalle 30" x 54" N scale layout and was going to use the plywood/foam as a subroadbed. I agree that 2" foam is strong enough and with 1"x4" framing and 1"x2" supports - this should work and be light enough for a small portable layout.

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Posted by fwright on Wednesday, April 20, 2011 11:55 AM

gnsoo

I have built a few layouts with a plywood base and plan on building a new layout after I move to a different house.  I was wondering the pros and cons of either foam or plywood base, track laying, switch machines, wiring, scenery, running noise ect.

Personally, I find neither solution all that appealing.  I prefer an open grid - even for a shelf layout.  But then I don't like flat layouts, nor do I model a level prototype.  Depending on the situation, L-girder or box grid, using lumber or plywood strips all work fine to construct the grid.  L-girder with lumber is perhaps the fastest for an incompetent carpenter like me (cuts to the nearest 1/4" or so).  Thin plywood grid is the slowest to construct but is the lightest.

Subroadbed up on risers - can use spline, plywood, or foam for subroadbed.  Nice thing in the early stages is the easy access for wiring, switch machine and uncoupling ramp mounting, and the like.  With the subroadbed and roadbed on risers, scenery features can be any elevation I want them to be.

I have started with a flat table top layout (both foam and plywood) in the past, but ended up cutting out the subroadbed and putting it on risers later on (cookie cutter construction).  Somewhat wasteful of materials that way.

Comparing plywood and foam -

  • plywood requires basic carpentry tools - saws, drills, screws.  Foam takes knives and glue.
  • foam is much, much lighter.  But this only matters if you are carrying or moving a layout section.
  • foam doesn't change with humidity changes.  This is a non-problem in most homes with plywood - but the potential for problems are there with plywood.
  • foam is much thicker for the same structural strength.  This makes switch machines and under the track uncoupling ramps more difficult.  Areas where one track is above another requires change in support method due to foam's thickness.
  • foam doesn't hold screws or spikes or nails.  The usual solution is to glue wood or similar pads where switch machines or other items are going to go.  Glued construction works very nicely with foam.
  • foam doesn't hold taller trees upright very well either.

my thoughts, your choices

Fred W

 

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Posted by gnsoo on Wednesday, April 20, 2011 10:14 PM

I would like to say thanks to all of you that have sent replys.  Has anyone noticed a difference in track noise on foam or plywood.  I have always used cork roadbed.  All of my rolling stock has steel wheels.  Keep sending replys and hopefully this post will help other modelers as well.

JTG
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Posted by JTG on Thursday, April 21, 2011 12:18 AM

Well, the responses have certainly been all over the map! I guess I'll toss my two cents in:

2-inch foam on top of hollow-core doors. Lightweight but sturdy as all get out, and not prone to warping. I've been working with this as benchwork for the past year. Previously, I was a homasote and plywood  on open grid or L-girder kind of guy. Never again. Foam on a door is much superior, at least in my opinion.

No matter what you choose, I encourage you to select materials and design with portability in mind. You said you're moving soon. The next time you move, you should leave yourself the option of bringing your railroad with you.

Good luck!

 

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Posted by bogp40 on Thursday, April 21, 2011 10:00 AM

JTG

Well, the responses have certainly been all over the map! I guess I'll toss my two cents in:

2-inch foam on top of hollow-core doors. Lightweight but sturdy as all get out, and not prone to warping. I've been working with this as benchwork for the past year. Previously, I was a homasote and plywood  on open grid or L-girder kind of guy. Never again. Foam on a door is much superior, at least in my opinion.

No matter what you choose, I encourage you to select materials and design with portability in mind. You said you're moving soon. The next time you move, you should leave yourself the option of bringing your railroad with you.

Good luck!

 

Having a total thickness of :  2"+ 1 3/8"+1/4"= 3 5/8"  How well do your sw machines work having to use a wire that needs to be at least 4 1/2" long.  I would thing that the point rail pressure would be very weak even using a heavier piece of music wire. Has this been any problem and how have you solved it?

Modeling B&O- Chessie  Bob K.  www.ssmrc.org

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Posted by rrebell on Thursday, April 21, 2011 12:03 PM

I use foam and would never go back to ply!!!!!!!!!!!!!!! WS inclines are cheap if you just buy the starters and use scrap foam for going higher, I buy the 2" @ 2'x4' foam for the base but all else I use free foam shipped with packing stuff. I also should note that after I carve the basic landforms with foam I cover all with plaster cloth that you can buy cheap in bulk from the likes of ASW.

JTG
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Posted by JTG on Thursday, April 21, 2011 12:25 PM

bogp40, sorry I can't answer on that one, as I'm using all ground throws. But while I have no personal experience with switch machines mounted under hollow-core doors, I've read that it can be done. I just didn't note the particulars because I have no plans of using 'em anytime soon.

 

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Posted by Anonymous on Thursday, April 21, 2011 1:26 PM

Just completed a big expansion of the layout earlier this spring (see my other posts for pics of 2" foam installation), but I because I incorporated my original layout which is on 3/4" and 1" Medite (high density particle board) I have a constant noise comparison as trains run from one section to another...

......and foam is much much noisier....by a matter of many decibels.

Don't use particle board, but certainly I would recommend plywood over foam if you do not anticipate wild climate control issues.

JTG
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Posted by JTG on Thursday, April 21, 2011 2:32 PM

Cisco, what did you use to support the foam? I think that might be a factor as far as noise goes.

I had read about noise concerns from some modelers, and considered that before I made my decision to go with foam. I can't do the "side-by-side" comparison, so I'll bow to your experience there, but I haven't noticed any undue noise while using foam on a hollow-core door.

Then again, I'm in N scale, so that is also likely a factor.

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Posted by gnsoo on Thursday, April 21, 2011 4:03 PM

The reason for asking is my current layout is 8x12 with a 2x8 wing.  It is designed to either add sections or wings.  The layout is an open grid with twenty four inch depth on a plywood base and can be taken apart in sections.  After visiting a layout with 30" depth, I saw how much running space and scenery could be added.  I am modeling in HO and run great northern and soo line in the 60's . I have a main line and sidings for each.  This eats up a lot of space and doesn't leave much room for other buildings and scenery.  I have thought about running just one at a time but I like running two different railroad names at the same time.  I guess i might have to wait untill I move to see how much room I am going to have available.  Any insight and suggeations or openions are always welcome.  I just have track ran at this point with no scenery.  My plan is to be in the next house for a very long time and want to have a very nice layout to build.  I like to have a starting point and industries to switch at as well as have a continious run plan.  Thanks for your input.

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Posted by Anonymous on Saturday, April 23, 2011 3:19 AM

JTG

Cisco, what did you use to support the foam? I think that might be a factor as far as noise goes.

 

Yes, I think the scale might have a lot to do with it. 

I have the foam glued to half-inch plywood sheets which are screwed to two by four benchwork, supported on legs on carpet, but also screwed to wall studs (and that last point may have something to do with it).

My work is seen at this rather terribly long post elsewhere in this forum about my construction

http://cs.trains.com/TRCCS/forums/t/186585.aspx

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