The cracks them self would make a start on drainage ditches.
Cuda Ken
I hate Rust
Thanks guys. I'll need the flex since the set is in the garage and it gets pretty humid here. I'm going to try the Silicone Caulk.
The foam is pretty level. There's a couple spots of thin overlap that is only there thanks to my awesome cutting skills. I was waiting to see what I should use to fill in the gaps before I went in and cleaned up the cuts. I'm planning an Eastern North Carolina type scene which is pretty flat except for the drainage ponds and ditches.
Woodland Scenics makes a foam filler for those cracks that's supposed to be fairly flexible. Vinyl patching compound will work too. I would grind out the gaps a little more to get more filler down into them. More filler, less chance for cracking.
What are you planning for that area?
If it's track, then you really want it to be stable, preferably firmly attached to the benchwork underneath so there's no "tectonic plate" motion between the pieces. If it's nice and solid, though, you can simply shave off the high spots with a knife or rasp file until it's all level.
Even for scenic areas, I'd still recommend making sure the pieces are not shifting relative to each other. I'm not a big fan of flat scenery, so I typically add scraps of foam on top to bump it up a bit, and carve ditches and low spots as well. I usually use plaster cloth to smooth the edges out a bit, and then cover the whole mess with Gypsolite to give me a rough ground surface. Gypsolite will easily bridge over small gaps like you've got.
The one thing you do NOT want to do is put a lake or pond there with something like Envirotex. That kind of material is very good at finding the smallest hole to flow down into, and the lake will end up on the floor beneath your layout unless you seal it very well before pouring.
It takes an iron man to play with a toy iron horse.
I would use water based latex caulk which you can also use to attache both your road bed and track to the bed. BUT, from the pictures the foam pieces don't appear to be level. If this is the case you would not want to lay track on them because of the resulting track problems. If just scenic areas then no problems.
Bob
Don't Ever Give Up
It depends on how much flexing and moving around you expect the layout to do.
If the answer is "not much, it's pretty solid", then you could go with sheetrock joint compound.
If the answer is "it's going to get a lot of movement and abuse", then you probably want to try something that stays more flexible and has better binding qualities. Like a siliconized vinyl caulk.
I have figured out what is wrong with my brain! On the left side nothing works right, and on the right side there is nothing left!
Sorry for the horrible pic but what would you pros recommend for filling in these cracks in my foam?