Woodland Scenics Realistic Water over foam base and the outgassing bubbles

[Dave V]

I know I've brought this up before, but am looking for any assistance the a$$hat collective can provide.

Any time I've used Woodland Scenics Realistic Water (the self-leveling room-temperature acrylic resin pour) over an extruded Styrofoam scenic base, after about 6 months I start getting large bubbles in the water like those in a pizza crust, clearly pushing up from below.  This happened above the waterfall on the Juniata Division, in the Dolores River on the RGS, and the entire length of the Frying Pan River on the Colorado Midland.

Between TRW and the other forums, consensus seems to be that this is caused by outgassing from the Styrofoam.  Given that I have every intention of continuing to use extruded foam as a scenic base for all of the other reasons it's so darn useful...I'm still struggling with the water issue.  I've had some luck with using the super-thick acrylic gloss medium for rivers with a minimum of bubbling, but it doesn't self-level and is hard to apply over a rocky channel.

Has anyone successfully sealed Styrofoam and been able to use WS Realistic Water without outgassing bubbles?  To be clear you'd have to have used the product probably a minimum of 6 months ago to be sure to have avoided the bubble issue.

EDIT:  Having had the problem twice in N scale I used plaster to seal the Dolores River on the HOn3 RGS...but it must still have been too porous.  If you've been successful, what did you use?

[dem34]

After reading through all the experiments DKS did with the G&D, from many a forum posts, and from me experimenting with small dioramas personally. The only long term solution seems to be to just make sure you don't have any foam at all underneath ones water features. Even sealed the outgassing appears to eventually fracture whatever you use to contain it and it doesn't ever seem to want to vent downward.

[Dave V]

After reading through all the experiments DKS did with the G&D, from many a forum posts, and from me experimenting with small dioramas personally. The only long term solution seems to be to just make sure you don't have any foam at all underneath ones water features. Even sealed the outgassing appears to eventually fracture whatever you use to contain it and it doesn't ever seem to want to vent downward.

I was afraid of that...but then that begs the question:  Could I simply line the river bed with thin styrene or Masonite or something?

I have several places in mind on the future CMRy where I will need to have water cascading downward from higher levels atop foam.

[CodyO]

@Dave V I would say use a 1/2" ply deck and then use SCULPTAMOLD to build up the areas you want for the rivers then Foamboard the rest.

Sculptamold also dries hard so that may even work to cover up the foam and prevent the gas from reaching the water features.
 

[DKS]

I'm not at all a fan of Woodland Scenics water products. I've tried them and always had problems. Indeed, I'm no longer inclined to pour any liquid product--the best of them stink to high heaven. My work with acrylic paint on smooth surfaces topped with gloss medium have been perfectly adequate. For bodies of dead-still water, I've always used smooth dark brown or black glass. As for cascades and moving water, I use clear silicone caulk dry-brushed with white paint.

[nuno81291]

Put a piece of Masonite or thin ply down for the base of the river.

[Chris333]

Wood base:
https://photos.app.goo.gl/wh4Kj9D9BJm6JjWNA
Wood base:
https://photos.app.goo.gl/zBM2qkXWKe4nPV6j9
Wood base:
https://photos.app.goo.gl/NBfukXKAze6WzEpU8

It's just an extra trip to the garage to cut another board. But yeah you need to plan everything else for the wood thickness to be there.

[Dave V]

@Dave V I would say use a 1/2" ply deck and then use SCULPTAMOLD to build up the areas you want for the rivers then Foamboard the rest.

Sculptamold also dries hard so that may even work to cover up the foam and prevent the gas from reaching the water features.

Sculptamold is just as porous though.  But as for 1/2" ply...wow, that's way thicker than what I need for a little portable layout!

Wood base...yeah, that seems like the thing.  I still wonder about styrene though.

[muktown128]

I was thinking of some sort of barrier.  This may be a crazy idea - what about aluminum foil or clear plastic wrap - Saran wrap or Glad wrap or something like that?  Maybe try Flex Seal, Flex Tape or Flex Paste? 

[Dave V]

I was thinking of some sort of barrier.  This may be a crazy idea - what about aluminum foil or clear plastic wrap - Saran wrap or Glad wrap or something like that?  Maybe try Flex Seal, Flex Tape or Flex Paste?

I wonder if foil or plastic wrap might have too much "give" against the force of the outgassing...  Flex seal OTOH, you may be on to something!  Is it foam safe?

[DKS]

I'd place a vote for styrene on top of foam. Lightweight, 100% sealed and perfectly smooth.

[Steveruger45]

Aluminum foil might work toned down with some rattle can paint. It would sure keep it light.  Maybe do a test piece to prove the concept.

[muktown128]

Per the Flex Seal website, foam is included in the list of recommended surfaces.  Website link below.

https://www.flexsealproducts.com/product/flex-seal-liquid-rubberized-coating/

[Steveruger45]

Cool.  Plus you can make boats with this stuff too.😊

[Chris333]

That just means you can apply Flexseal to foam and it won't attack it, not that it will make it impervious to gases.