Inuslation Foam top vs Plywood

I have 1" thick blue foam on 1/4" ply and my track screws are long enough to reach the ply. This may defeat some of the sound deadening qualities of the foam, but it is very light and my layout is portable. There is no reason to use the foil backed foam The dense blue and pink are available at the big box stores.

For a permanent layout, I would actually consider the L girder construction the HO and scale guys use if I were going for realism. 

Also, I forgot to add- foam glues very well with adhesives available for foam. These are in the caulk gun tubes- just check the labels. Also available at BBS.

I guess I'm old-school, I wouldn't use just foam.  My new layout is using 1/2" multi-ply birch, that's topped with 1/2" Homasote.

Alan, I used Elmer's glue to attach the foam to framework. If you cut the foam you will want to find blades to fit your sabre saw, you will want the ones without teeth, they are like knife blades. They do cut clean but you need to cut carefully where you want to join sheets together. If you are patient you can use the same Elmer's glue to join them, otherwise I am sure there may be a water base contact cement that would work, the solvent base glue will eat the foam. I used low temp hot glue to attach my track to the foam with a dual temp glue gun set to the low temp, the high temp will melt the foam. How do I know?

Ray

I tried that. RealTrax on 1” rigid foam with open L-girder underneath and no plywood base is going to be noisy. I’m not sure how much a plywood base would help, but foam is not the sound deadening material people think it is. Yes, it may help reduce noise traveling through walls, etc., but when you put trains on it, the sound actually increases, especially beneath the decking. It’s mostly for sculpting landscape features and I only used it to save weight on a Christmas layout that had to be moved/stored. I added batting under the tracks and added a skirt around the layout. That helped, but it was still hard to carry on a conversation with trains running. And this was in a 3-car garage with the doors open. YMMV

I used a foam base for lightness and portability.  There is no sound deadening.  The dense foam actually acts like a drum magnifying the sound.  With that beautiful base I would follow GRG's method of plywood and homasote.  You can use the foam for building terrain but not supporting the track.

Chris

Like others have said, I think you are better off using a thin (3/8" - 1/2") plywood top before installing a rigid foam base (3/4" or 1") from a big box store w/o a foil backing.

 The foam does not dramatically reduce noise, but it does seem quieter than plain plywood. In addition, it provides a nice medium for simply gluing and pressing in scenics like telephone poles and trees on your layout rather than having to drill through plywood.

I have always used a construction tube adhesive (like Liquid N**ls) to adhere the foam to the plywood and placed heavy items (books, tools, etc.) on top to weigh it down overnight. I use a utility knife and a very sharp 10" commercial chef's knife to cut and trim the foam. I also tape any seams with duct tape which seems to hold up very well. You could also use a flexible joint compound or similar product to fill in the seams, but I haven't found it necessary.

Depending on what you are looking for, I typically paint the foam with an earth brown latex paint in sections and sprinkle with green and yellow fine turf while still wet to hold the turf in place and, when dry, brush very lightly with a dry utility paint brush to spread the turf around and remove any blotchiness and then spray with a high hold hair spray to keep the turf in place.

Pic of latest project attached.

gunrunnerjohn posted:

I guess I'm old-school, I wouldn't use just foam.  My new layout is using 1/2" multi-ply birch, that's topped with 1/2" Homasote.

I am in Alabama and cannot find homasote. Where did you find it?

Warrenville's base is 5/8" plywood, no foam or homosote.

I LIKE the sound of multiple Postwar trains running, e-unit buzzes, and bicycle type horn and air whistle sounds, better than digital train sounds. But this is me, different tastes in this hobby are what makes our small worlds go around (pun intended).

I enjoy seeing what you guys are doing and look forward to updates of your progress

It's readily available up here in PA, don't know about Alabama.

dogdoc posted:

I am in Alabama and cannot find homasote. Where did you find it?

http://www.homasote.com/wheret...p;State=AL&City=

The drop down state options shows cities where retail stores in Alabama stock it or will order it.

Sooner or later, you will need to on the train table. Will the open grid with foam support your weight?

In testament to those who have said foam is noisy.  I agree completely.  Here’s 2” blue foam over a 1“x6” wood grid on the xmas layout.

I am in the camp using plywood topped with Homasote for tabletop and track base on a permanent layout.  I use foam for scenery only on a permanent layout.  I have a 2" thick foam base for the Christmas layout for portability, and it is noisy like Ted's.

Poorly supported foam will eventually sag. Don't ask me how I know this...  I recommend supporting it with 3/8" plywood or better.  Not certain how well it works as a sound deadener, but having it under your track allows you to cut it out and have things immediately next to the track below grade.

Chris

LVHR

I went all out (my layout is not in the running phase, so I don't know about the sound or lack thereof), I have 4" of foam over 3/8" plywood, which in turn is on a ladder-style base with cross pieces on 16" centers. While I don't plan on going on the layout, the plywood alone did hold my weight at one point.  I decided to experiment with foam because I was too chicken with my first layout in decades to do open grid, by using the 4" I can easily do sub track level features like ponds, rivers (and an 'abandoned' rail line). The foam seems pretty strong. With sound, I'll likely use roadbed under the track (if I ever get that far, don't ask me whether track planning is my favorite thing, it #((($! isn't. 

Thanks for the helpful responses!

After reading through your posts, I'm leaning towards plywood topped with 1/2" foam. I have a 3/4"x 3 'x 6' green painted sheet of good ply from my last layout.  Going to rip it to support the track and leave some open areas for scenery above and below grade.

Always wanted to try Homasote, but the BBS don't carry it on the west coast. 

Here's my track plan, simple and using track I already have.  Very much a test layout where I can revive my Legacy and DCS gear and test locomotives.  Lower track will be MTH RealTrax and upper loop O-27.

We're off to the coast for a night - have a good weekend everyone.

Alan

PL 300 for your foam board adhesive. It works. I've used it to adhere extruded foam to plywood on two other layouts. I am using an exclusively foam base, but I am using vented elastic resin shelving to adhere them to. I agree with others who recommend thin plywood base in the case of L-girder construction.

Make frames out of 1" x 3" strips of wood and 1" x 4" strips of wood screwed together. 

All you need is 1/4" thick plywood that is sealed by painting it with colored latex paint primer.

You can drill holes for wiring before painting.

Screw the plywood to the frames. Seal everything with a coat of colored latex or acrylic primer paint.

Then put layers of 1" to 3" thick sheets of Extruded Polystyrene foam on top of the framed plywood sheet.

Andrew

Liquid Nails has adhesives that should hold foam to plywood.

For realistic scenery contours like hills and rivers, it usually requires a 5" to 6" thick total amount of foam layers.

Andrew

Someone posted on here a few years ago about foam catching fire very readily, and (based on a bad experience) strongly recommended against it ...

DAB

Wood catches fire also.

The super dense extruded polystyrene foam is what to use for O scale weight models. 

When do you ever have open flames around O scale models?

If you are using live steam with live flames, perhaps you need to get a track set up in a rock garden.

Andrew

I have used just foam on both O and ho layouts without any problems. Make sure you have good support though. Also I used 2" for the O and 1" foam for the Ho. 

I used white glue to hold the track down and it is very easy to remove if needed. 

Dave

I hope I am not too late with my suggestion.  But I see a number of individuals mentioning Plywood.  I have been using OSB instead and saving some money.  And then Homasote on top and then I also use Track Bed under the track.  Very quiet.

Jim, I must say I agree.  I had some plywood on hand, but bought some OSB last year.  So far I like it, and the price too!!

Thanks Mark,

I always like seeing your avatar next to a post.  It means what is being stated is pretty much always correct.

Thank you, Jim.  I try to not type if I don't know or haven't tried it. 

Once early on in my time on the forum, I stated something that wasn't so.  It was an opinion that was not based on fact.  A nearby member on the Forum called me on it.  I am in gratitude to him to this day.

Loose-Caboose posted:

I hope I am not too late with my suggestion.  But I see a number of individuals mentioning Plywood.  I have been using OSB instead and saving some money.  And then Homasote on top and then I also use Track Bed under the track.  Very quiet.

IMO, using OSB to save a few bucks is probably not the place to cut corners.  The birch multi-ply I used on my 12 x 23 benchwork was less than $300 total, and it lays perfectly flat and will stay that way.  OSB is not nearly as good a foundation for the platform. 

gunrunnerjohn posted:

Loose-Caboose posted:

I hope I am not too late with my suggestion.  But I see a number of individuals mentioning Plywood.  I have been using OSB instead and saving some money.  And then Homasote on top and then I also use Track Bed under the track.  Very quiet.

IMO, using OSB to save a few bucks is probably not the place to cut corners.  The birch multi-ply I used on my 12 x 23 benchwork was less than $300 total, and it lays perfectly flat and will stay that way.  OSB is not nearly as good a foundation for the platform. 

John, This Forum is always a great place for ideas and sharing experience.  Since I have some with track laid, I will have to see how my OSB does in the course of time.   or 

Only homasote anywhere close to me is special order and I doubt they want to do it for 2 or 3 pieces . Any good homasote substitutes?

dogdoc posted:

gunrunnerjohn posted:

I guess I'm old-school, I wouldn't use just foam.  My new layout is using 1/2" multi-ply birch, that's topped with 1/2" Homasote.

I am in Alabama and cannot find homasote. Where did you find it?

Same place I can't find it in Arizona.  Home Depot and Lowes couldn't even find it on their computers.  I'm looking for an alternative and may go with foam.

I used plywood, 1" foam, and ceiling tile on top. I consider my Fastrack to be very quiet. I used L- girder underneath, and have had my 215#s on there a lot to do far scenery. I was able to buy all the tile as damaged, so it was not expensive. Worked very well for me.

On the subject of sound proofing has anyone tried products known as “mass loaded vinyl”.   Link is example from Home Depot and a bit pricey at $125 for 4.5’x10’ roll. 

https://www.homedepot.com/p/Xt...-11054-10/304268301?

Yikes, that would be a gold plated layout!  I can't imagine it's that good that you can't do it a lot cheaper!

For many years and many layouts, I have always used a plywood sub layer with two-inch-thick Extruded Polystyrene (pink or blue) on top, and either cork or Woodland Scenics foam roadbed under the track. There are a number of adhesives available that will glue foam to plywood and foam to foam (or some other material). I cut/carve the foam with saws, old serrated kitchen knives, and hot foam cutters (the latter leave no mess at all). I have never been concerned much about noise reduction because real trains make noise and I don't mind my model trains making some noise as well. I have never found that the noise caused by the underlying materials has detracted much from the train sounds (chuffs, roars, horns, whistles, bells, squealing brakes, etc.).

I built my original layout with 3/4 inch thick bagas board in Jamaica ( particle board in the states).  I made the addition, when back in the states, with 1/2 inch common construction grade plywood.  I laid the O27 track directly on both without a bed. The board with the plywood was much louder.  So much more that I cut up an old auto inner tube into 1/2" x 1 1/2" strips, punched holes in them for screws and places them under each tie and switches.  This reduced the noise to about the same as the particle board.  My layout was on the floor and walked on during yearly installation and removal after a few months.  The particle board is much heavier than the plywood also.

Today I would use cheap or used 1/2 " plywood with 1/2" Homasote or at least 1/2'' plywood with 1/8" cork or ceiling tile as a road bed.  Noise is an issue with me as I run four to six trains at once.

Charlie

Warrenville's base is all 5/8 " plywood except for one 4x8 sheet of particle board - I thought that I would try it out on one of many expansions.

I found it very heavy and hard to screw into, especially when using #4 track screws

 Can the foil backing on foam be used to create the “ground plane” that helps TMCC and Legacy signals?   

Harry736 posted:

 Can the foil backing on foam be used to create the “ground plane” that helps TMCC and Legacy signals?  

VERY BAD IDEA!  The ground wire should be above the tracks for best effect.  A huge ground below the tracks can actually couple the signal from the track to the ground and reduce the TMCC signal.  That's too much of a good thing in the wrong location.