# Foamboard bowing when wet?



## CSXDC (Jan 20, 2014)

Hello all. I am working on a small diorama, and am using a foam board as a base. When I started ballasting, I noticed that the foam is starting to bow in the middle after applying the glue/water mixture. Is the normal, and will it flatten back out? First time using foam board; normally just go straight on to plywood.

If you need to see the product, here it is: http://www.elmers.com/product/detail/951120?filterPath=office/3-16ths-inch/20in-x-30in/

Thanks in advance!


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## CSXDC (Jan 20, 2014)

Alright, decided to scrap the foam board. The warping got worse to the point that the track began to separate. I'm going to just be putting the track directly on to the finished shelf - that should prevent the moisture during ballasting from becoming an issue I would think.


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## DonR (Oct 18, 2012)

I am using a similar paper covered foam board from
Walmart Crafts section. Had no warping problems when
ballasting the tracks. Mine is glued to the plywood. Did
you glue yours?

Don.


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## fcwilt (Sep 27, 2013)

Why not typical rigid foam board as used for insulation? A 1" thick piece would make a good stable base for a diorama.

The item you tried likely had a paper based surface.


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## DonR (Oct 18, 2012)

fcwilt said:


> Why not typical rigid foam board as used for insulation? A 1" thick piece would make a good stable base for a diorama.
> 
> The item you tried likely had a paper based surface.



You are right. The WM craft foam is surfaced with paper. 
The 1" foam would be preferable, normally, I was seeing
the black surface as ideal for my yard underlay. Works 
fine for that. I use the W/S foam roadbed under the mains.

Don


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## fcwilt (Sep 27, 2013)

Assuming W/S stands for Woodland Scenics I too use their foam roadbed but I also used their sheets of the roadbed in my yard areas - the large sheets (12" x 24") can quickly cover the yard areas - and insures a consistent base for all trackage.

YMMV


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## CSXDC (Jan 20, 2014)

Thanks for the replies. I've began to ballast the tracks on the shelf and WS roadbed.


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## DonR (Oct 18, 2012)

fcwilt said:


> Assuming W/S stands for Woodland Scenics I too use their foam roadbed but I also used their sheets of the roadbed in my yard areas - the large sheets (12" x 24") can quickly cover the yard areas - and insures a consistent base for all trackage.
> 
> YMMV


I used a few sheets of the Woodland Scenics foam in a yard. It has
a spongy feel that I didn't like. That's why I tried the Walmart crafts
boards. More of a solid feel. Depends on your taste.

Don


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## fcwilt (Sep 27, 2013)

DonR said:


> I used a few sheets of the Woodland Scenics foam in a yard. It has
> a spongy feel that I didn't like. That's why I tried the Walmart crafts
> boards. More of a solid feel. Depends on your taste.
> 
> Don


It's the same stuff as the roadbed material so it seems like a good match - same sound deadening, height and other properties.

In the past I used cork and was very pleased, by comparison, with the characteristics of the W/S foam.


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