Foam Board vs Plywood/Homasote

Aside from weight, the biggest potential issue with foam board is strength. It is very fragile compared to plywood. So use it with alot of bracing and also where your layout is not going to get leaned on, bashed, etc.

Depends on your scale... For N layouts, foamboard is MORE than strong enough as long as you're not making it wide enough you have to actually _climb_ on the layout. I've done 3 modules now using foamboard, and have been _very_ impressed with the results. I'll be using it for my next incarnation of home layout, too - a multi-level around the wall monster. In N Scale magazine a while back there was an article about using 1" foamboard to build box beams that constituted the _entire_ benchwork. Even in HO, foamboard is of sufficient strength and stability that you can more framing members at least 24" apart.

However, you couldn't pay me enough to use AMI roadbed... (ICK!!) I use Woodland Scenics foam.

What is a good glue for joining two 8-ft long x 2-ft wide sections of

Some members of the club up here think that it is OK to use 1/2" utility grade plywood on the table, then glue the 2" foam boards on top and use that for marking track and using an hot "old" flat iron to depress areas below table level.

Yes, no problem, it works great. All our modules are built with foam as the core, with wood frame for support, strength and holding the clamps. It works fine, makes them light enough to manage without hurtng yourself, andf will even take the strain imposed by "fully loaded trains." Anything will fail if loaded enough, but remember you are using it to support your roadbed and trains, not yourself.

Liqoid Nails with the BLUE stipe is the stuff to use. It is for foam.

Liqoid Nails with the BLUE stipe is the stuff to use. It is for foam.

Thanks all for the helpful replies. I just read an article in MR about a small, modular lumber railroad setup that used blue board as its foundation. Also, they framed the blue board, as someone else mentioned here, for support.

I really like the modular, or semi-modular, idea so each module could be swapped out with another. Something akin to N-Trak concept.

Thanks again,

Robert

I just did a two foot wide 6'x18' "L" shaped modular layout with this exact construction method. 1. I framed it with 1x4 and every 18" I have a 1x2 cross member brace. The foam is glued to the top of the 1x2 and inside sides of the 1x4s. The 1x4's protect the sides and the few sticks of wood make it pretty strong. But when running trains on it, it acted like a sound board. It was loud. The wheel noise was magnified greatly. That is when I added the AMI instant road bed. It helped with the noise problem but brought a new set of problems. It would not stick well to the foam. It stuck to the track (and everything else just fine). I tried roughing up the foam first with sand paper - didn't help. I tried heating both the foam and roadbed - didn't help. I tried washing the foam with all sorts of cleaners/chemicals - didn't help. I finally ended up using straight pens just to keep it down. When I got the track in the final possition I stacked books on it and it seems to have stuck better. BUT that was just the beginning of problems. While I was careful to put a slick surface (scotch tape) under the turnout throw bars, I did not consider the continued sinking of the track into the roadbed. While the throwbars don't stick to the gooey stuff they are getting pressure from the bottom that prevents proper operation. The next plan is to completely remove the roadbed from under the throwbars - much easier said than done.

I will NEVER USE AMI INSTANT ROADBED AGAIN on anything. Not to mention it doesn't look very good anyway (too flat and wide).

Good Morning!

Not doubting your experience but it seems to defy logic

---- But *Logic* is Not Always Logical, Is It?!?!:)

Your observations *suggest* that the foam was transferring the sound laterally to the 1X4s which then these same 1X4s amplified the sound. Typical 1X4s would be softer than plywood and would theoretically absorb sound -- good you didn't cut plywood into

Any Other Ideas for this Sound Amplification??

We seem to have a tendency to overbuild and your lite-weight construction seems to have provided a good foundation, if not a quiet one.

I was going to suggest a framing of 1X2s topped with a thin-skin of 1/8" then topped by foam. The skin would keep the framing square and soundly gluing the foam to the board should give Very Good Rigidity with little flexing. Wonder if this would be more acceptable sound-wise? But the 1/8-inch skins can be expensive.

The skin would prevent punching a hole clear thru the foam if someone in-advertently leans on it -- won't rule out a depression in the foam, but that would happen even with 1-inch plywood underneath!

What have you tried in place of the AMI-roadbed?

Jim

Well this is a modular layout that I take to shows so my theory is that the foam acts like a speaker cone. with a 2" baffle. The sound goes straight down and reflects off the hard tile/wood/cement floor.

I know someone who is now building modules like this. I'll make it a point to get over to their layout at the next GATS (February) and take time to listen to it.

On the foam, nothing yet. Up until this experience I've been a cork/homosote/micor on plywood person. This is too heavy for modular units (My daughters original 2'x4' we inherited weighs about 20 lb.., the new one we built from scratch weighs less than 4). But I believe I'm going to try the spongy foam road bed from ?? umm woodland scenics? I'll try anything once. If it doesn't work I'll go back to cork until the next new fangle thing comes on. I really wish someone would make

Aircraft wings are built from foam laminates and glue. I'm sure that's more than strong enough for a layout. If you are really concerned about structural integrity, glue the foam boards to a pair of parallel, kiln-dried 2"x2"s.

Remember, it's a layout, not a mechanic's workbench. Use foam and you will have a lot more money left over for the important stuff.

-- Moderator of:

That will keep the foam supported well so it should work.