Better way to fill in the gaps in Layout?

Matt...

My layout is built more as an open grid framework.  But I'm using the 2" foam in a very similar manner.  My opinion about the 'drum' issues re noise is that this will become minimized as you apply structures, ground cover, trees, rock castings, etc., etc.....all of which change/absorb the noise transmission quality of a rigid structure such as foam board or even plywood.  Don't give up at this point.  Take a break and apply scenery/structures to an area that seems to have a noisy quality, and see if it stays the same....or quiets down.  My experience is the latter.

The advantage of the 2" foam inserts that I'm using is being able to lift them from the layout and work on the scenery stuff at a common work place/bench.  I got the idea from one of the big commercial layout builders.  All of the scenery is done in 'puzzle' blocks.  The final installation involves dressing the joints, blending it together.  The other advantage is being able to change the scenery in a finite area later on without disrupting surrounding areas....even if you have to cut a new foam block.

Keep going.

But, that's just MHO.

KD

Thanks!  

Great to know others are doing similar things.  I'll keep going and see what happens. 

I just didn't want to go through all the work only to find out I'd have to rip it all up again. 

Perhaps using a softer foam (such as upolstery foam) instead would be quieter, or you could try gluing a thin (1/4" thick) piece of of upolstery foam on the back of your extruded foam, or between it and the benchwork, to try to absorb some of the noise. If you could find some of the "egg crate" looking molded foam like what is found in shotgun cases and camera boxes would be even better. I've seen it glued onto walls to deaden reflected sounds...

Bill in FtL

This is a really interesting idea. 

I used fiberglass window screening stapled between the gaps then I mixed a 1/2 part plaster of Paris and 1/2 part powder drywall compound then I took a 4" paint brush and brushed it on it dryed hard as a rock I could ripple the screen to create rocks it was very cheap and easy way and when it dryed and I wanted to change it I just cut it out as you can see the pictures the whole area around the turntable and between the tracks was done with this process I use the drywall compound because plaster dryed fast so the drywall compound slowed the drying process

I don't have any flat, reflective surfaces in my train room to bounce the sound around.

My train room is carpeted with pile carpeting. 

The walls have racks of trains on them so they are fairly irregular shaped.

On the layout I used astroturf carpet stretched over and stapled to sections of 1/2 inch plywood to build the layout table/surface.  The plywood sections sit on top of 2x4 leg supports.

I would think that the larger flat solid surfaces on your layout pics may be acting like a drum surface for any sounds that get created on top of it.  As previously mentioned, when you do the scenery and buildings that should be somewhat mitigated.

You might just spread some thick bath towels on your layout area and some small cardboard boxes or cans of soup to simulate the bldgs and see if you still get that much noise.

Just MO