In looking at past posts, there is some confusion on WHEN to put down the ground foam. Some say to spray or brush on the adhesive BEFORE the foam is sprinkled on the layout. Others have said to treat it like ballast and put it down first, then glue it in place. The foam is much lighter in weight than ballast so it may blow away when applying the glue mix. BTW, I am trying to adhere the ground foam to the painted 2" foam on the layout. No plaster to absorb the water and prevent the adhesive from sticking with the ground foam.
From all the books, articles, and posts I have read, it’s glue (or paint) first then ground foam for the first layer. You can sift the ground foam over wet paint and if the paint isn’t too thick, the ground foam won’t absorb the color of the paint or drown in it. For areas you don’t want to paint (or repaint), brushing on some diluted white glue/matte medium/etc. and then spreading the ground foam works.
Now after it all dries, you’ll find some missed areas or thin spots or places you’d like to have more or a different color or texture. Since you already have a layer of dried ground foam down, sprinkle, spread, drop the additional down and then lightly apply the diluted white glue to those spots. This is where I would also add “bushes”, “shrubs”, or “clump” pieces and dribble the glue over them as well.
The best part about scenery…if it doesn’t look good, apply more/another layer/color/whatever to hide the first attempt.
After the ‘ground’ is painted with a ground color, I usually ‘paint’ the area with diluted white glue or Matte Medium(Scenic Cement). I apply the grass cover at that time. I sometimes ‘mist’ the area later with 71% alcohol and then use a pipette or large eye dropper to add more Matte Medium. This sort of glues all of it together.
I have just started top try ‘static grass’ and I have found that a ‘thicker’ application of the white glue or Matte Medium works well to hold the grass up while the glue dries.
Bruce, I’ve used both methods. With the “dry” method I’ve found that the ground foam tends to blow away when the wetting agent is applied. I sprinkle the ground foam directly onto the layout dry. I use wet water as a wetting agent (the smell of alcohol bothers me) but many prefer alcohol or a water/alcohol mixture. What I’ve found works best is to use a spray bottle which produces an extremely fine spray, like one of my wife’s old body spray bottles (the little bit of perfume stuck to the bottle isn’t that bad either) and spray it up in the air and let it fall onto the ground foam like rain. Once the ground foam looks wet, then I spray it directly on. Once it’s thoroughly saturated I apply the diluted white glue by dribbling it from an old white glue bottle and unless I pour it so heavily that it runs like a river, it doesn’t disturb the ground foam.
For the “wet” method, I paint the area with full strength white glue then sprinkle on the foam. Once it’s dry, I vacuum up the excess and touch up the bald spots. My experience is that i get more bald spots and more loose material with the second method, so I prefer the first.
To apply the ground foam, i use spice bottles. I bought a couple of sets in racks at a discount store and use them to apply ground foam and ballast and gravel as well as dirt. The spice bottles have holes in the lids and I just shake the contents out.