# My 1st Layout - Beginner Questions



## mbeutler1203 (Nov 28, 2015)

So I just built the table shown in the image at the bottom of the post and am ready to move onto the next step. I followed the plans shown here but swapped the 1/2" plywood for 2x4's.

So my first question is: Most people would now nail a 1/2" sheet of plywood to the frame followed by pink foam board but I am wondering if it would help if I put some sort of gasket (rubber potentially) between the frame and the underside of the plywood where the two surfaces will contact. I think this might help with sound reduction. What are your thoughts?

Thanks in advance for your help!


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## Lemonhawk (Sep 24, 2013)

Skip the plywood and just put 4-6 inches of blue or pink foam. Isolating the foam will do nothing for reducing noise. Looks like a real solid table!


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## CTValleyRR (Jul 26, 2014)

I agree. Go straight to foam. It will be plenty sturdy.

If you're really worried about noise, you'll want to insulate your track from your layout surface. Foam roadbed works very well for this (although personally, I've never been bothered by the noise on a finished layout).


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## DonR (Oct 18, 2012)

I have no experience using that thick foam, so I
am not at all disagreeing with Lemonhawk or CtValley.

I find myself having to put a good amount of my
body weight on my layout top to make some reaches
at times. Will that foam be capable of supporting a
man leaning on it heavily?

Don


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## mbeutler1203 (Nov 28, 2015)

Lemonhawk said:


> Skip the plywood and just put 4-6 inches of blue or pink foam. Isolating the foam will do nothing for reducing noise. Looks like a real solid table!


That is much more foam than I was anticipating. I can do plywood with 2" of foam for less than 6" of foam without plywood.

Also, I have heard that the thicker foam has some reinforcement fiberglass strands in the boards that make it very difficult to carve out. Any truth to that?


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## CTValleyRR (Jul 26, 2014)

DonR said:


> I have no experience using that thick foam, so I
> am not at all disagreeing with Lemonhawk or CtValley.
> 
> I find myself having to put a good amount of my
> ...


If your supporting joists are on 16-24" centers, certainly. I am 225 pounds, and my son is 185. We have 2" foam on 24" joists, and both of us have leaned on the table, feet off floor, without a problem. If your benchwork is robust enough, the foam can take it.


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## CTValleyRR (Jul 26, 2014)

mbeutler1203 said:


> That is much more foam than I was anticipating. I can do plywood with 2" of foam for less than 6" of foam without plywood.
> 
> Also, I have heard that the thicker foam has some reinforcement fiberglass strands in the boards that make it very difficult to carve out. Any truth to that?


I think what he means is layering the 2" foam boards. This gives you sufficient depth under your layout to make deep ravines / watercourses and other severe terrain relief. 

If you read my previous post, you'll see that this is not required for strength.


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## Hank Rearden (Dec 30, 2014)

If you have no plans to dig into the foam then it would seem plywood is the way to go. And for sound deadening, I think a good roadbed is all that is needed. No?


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## Cycleops (Dec 6, 2014)

Nice bench work. Is it going to be N or HO?


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## ErnestHouse (Sep 6, 2015)

On strictly a sound basis, consider that all sound is pressure waves. They are very hard to stop as they easily reflect (bounce) off hard surfaces (such as plywood) of all types and they radiate in all directions. So putting rubber on the frame to isolate the plywood isn't going to be very effective in stopping the pressure waves that the plywood is reflecting or transmitting. Managing sound is about absorbing the pressure waves. Road beds work at doing that closest to the source. Foam is the next layer of "defense". I don't have experience with foam but intuitively, more foam will do far more than isolating plywood. And eliminating the plywood even more to reduce sound reflections.


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## deedub35 (Jan 29, 2014)

When I built mine I went with a 1/2" sheet of plywood, then 2" rigid foam board, then Woodland Scenics foam trackbed, then track, and then ballast. I do question the sound deadening of the foam trackbed with this method though. If it was just the foam trackbed between the track and the substrate then I can absolutely agree that the sound deadening would be most effective. However, as soon as you ballast everything the sound has a direct channel from the tracks to the substrate through the rock hard ballast. What do you guys think?

I am in construction and there is a newish product called Green Glue. It is used to help minimize noise transmission between construction materials. I'm curious to see if this product was used between the benchwork and plywood if it would help with noise reduction. You want to give it a try????


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## ErnestHouse (Sep 6, 2015)

I agree rock ballast is hurting not helping. Keep in mind the sound source is truck vs track. Isolating the substrate from the support structure is only reducing the sound transference to the floor and beyond. It does nothing to sound transference and reflection into the air directly from the source, ballast and table. For a given truck and rails, the maximum improvement is to absorb the sound (prevent reflections) at the source. Rock ballast is reflecting it directly into the air completely unaffected by insulating substrate and supports. Track bedding can absorb sound transferring through the ballast but not reflected into the air. Track directly on plywood turns the plywood into a huge speaker reflecting sound into the air on both sides of the plywood. Insulating it with foam and track bed helps diminish that effect and so on down the chain to the floor.

Actually, sound treatment of the train room walls and floor is probably more significant than you would think because it affects the all the noise reflected directly and indirectly into the room. You may not be able to stop the sound generation at the source but room sound treatment can stop it from reflecting on the room walls. Think anechoic chamber as the ultimate in preventing reflections. 

https://upload.wikimedia.org/wikipedia/commons/0/0a/Radio-frequency-anechoic-chamber-HDR-0a.jpg


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## CTValleyRR (Jul 26, 2014)

As I said before, I personally think all the hullabaloo about sound deadening is much ado over nothing.

That said, as a former submarine officer and a current employee of the world's foremost submarine maker, I know a thing or two about sound propagation. Forst of all, while vibrations are conducted through solids rather well, every change in material type causes some attenuation. Furthermore, rigid materials (plywood, insulating foam panels) transmit sound rather well. Soft, spongy ones (cork, foam roadbed) not so well. 

Rock ballast is not much of a problem. It is not a uniform density, but a mixture of very dense rock and less dense adhesive, and actually doesn't transmit sound that well. Using a more flexible adhesive like matte medium improves this even more. 

While sound waves reflect very well off of flat, hard surfaces (plywood, foamboard), the rough surface of the gravel ballast and the soft texture of scenery materials actually does a pretty good job of breaking up those sound waves.

So, install your track on foam or cork roadbed, and ballast it or not as you desire. Add scenery if desired. Then run trains. At the risk of being blunt, if the noise level bothers you at that point, you need to find a new hobby.


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## ErnestHouse (Sep 6, 2015)

What @CTValleyRR said.


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## traction fan (Oct 5, 2014)

*Foam on plywood*



mbeutler1203 said:


> That is much more foam than I was anticipating. I can do plywood with 2" of foam for less than 6" of foam without plywood.
> 
> Also, I have heard that the thicker foam has some reinforcement fiberglass strands in the boards that make it very difficult to carve out. Any truth to that?


 I agree with your idea of 1"-2" foam over 1/4"-1/2" thick plywood. The plywood isn't primarily for strength. As said before, if your joists are reasonably close together the foam alone can support quite a bit of weight. The reason I recommend having the plywood is to have a firm surface to attach switch machines, wiring, and whatever else you want attached to the bottom of the table. Also If you leave the plywood unattached to the frame; and glue the foam to the plywood, you will be able to do that attaching with the table top upside down, or sideways. This is much, much less work than trying to do all that from below. You could even cut the plywood/foam into sections. They would be easily moved to a workbench or table where you can sit while working on the Railroad.

Traction Fan


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