Woodland Scenics Realistic Water over foam base and the outgassing bubbles

[wazzou]

I think FlexSeal is pretty expensive and a little overkill when Styrene will likely be just fine.

[MK]

Heavy Duty aluminum foil would be thicker.

[Chris333]

a 2x4' sheet of 1/8" Masonite costs less than a 8.5x11" sheet of styrene, just sayin'.

[wazzou]

a 2x4' sheet of 1/8" Masonite costs less than a 8.5x11" sheet of styrene, just sayin'.

How about a For Sale sign?   

[Dave V]

All excellent points!

[Chris333]

But how do the gases affect styrene   

[Dave V]

But how do the gases affect styrene   

Dunno!  One hopes it can't penetrate styrene.  But then again hope is not a strategy.

[Chris333]

Just kidding, but don't use foam.

[wazzou]

But how do the gases affect styrene   

The lable said 99.9% safe.   

[MK]

What's the other 0.01%?   

[dem34]

What's the other 0.01%?   

Resonance Cascade.

 

[LIRR]

Use a piece of 1/8 plywood over the foam as a riverbed...sand smooth and paint. I’ve had the WS product on plywood in 2 locations for a couple of years without any problems

[Dave V]

Not sure when I'm going to start benchwork (before August is through though...I want to do the work in the garage and winter will be here in about 7 weeks) but I'm now planning on using some kind of barrier, wither veneer ply, Masonite, or styrene.  As my Virginia-raised wife would say, "ya'll've made a compelling case."

[jon612]

I'm curious if your problem might be related to the adhesive you are using to secure the foam (extruded polystyrene?)

Most adhesives that come in a tube are not ideal for bonding 2 pieces of polystyrene together. If it stays wet in tube, it will stay wet between the foam for a long time, slowly releasing gas. Most of the adhesives in a tube have a shelf life/ expiration date for this reason. It will dry out but never properly cure.

[Dave V]

I'm curious if your problem might be related to the adhesive you are using to secure the foam (extruded polystyrene?)

Most adhesives that come in a tube are not ideal for bonding 2 pieces of polystyrene together. If it stays wet in tube, it will stay wet between the foam for a long time, slowly releasing gas. Most of the adhesives in a tube have a shelf life/ expiration date for this reason. It will dry out but never properly cure.

This isn't an issue.  I use foam-compatible construction adhesive only.  Plus it happens in areas where I specifically haven't used adhesive either because the water channel is only part way dug into a 2" slab of foam or because I deliberately left an area unglued in anticipation of it serving as a water surface.