Making XPS foam scenery tougher

[6mmfan]

I’ve been making some XPS foam scenery (mostly walls) and I was looking for tips on how to make the foam more resilient? ie less prone to dents or breaking?

So far I have thought of mixing PVA Glue or Modge Podge in with the paint to make the surface tougher. Also cocktail sticks pushed into the foam as support.

Any other ideas?

[Spooktalker]

Don't know how smooth you want your walls. If you want a stucco effect you can do a knock-down texture in miniature with acrylic structure medium, the kind made of powdered marble and a binder. I've had great success thinning it down, troweling it on, dabbing it with a paper towel to pull up little points, then waiting the right number of minutes before knocking it down again with the trowel. The quality can be as good as a prize winning diorama if you're careful.

Watered down pre-mixed concrete patch can make a tough surface. You can water it down to melted ice cream consistency or thinner. The stuff I have access to at local stores is not like it used to be, though. It has a much courser sand than the stuff I used to get many years ago.

If you want smooth walls, you could try coats of urethane, though you might have to seal it with PVA first. You'd have to test it. This would take a lot less effort than the above two methods, too.

[6mmfan]

Interesting ideas. BTW here a picture of my walls so I'm looking to brush something on quite thin.



Cheers

[CookAndrewB]

I've been doing a texture with PVA (basic, not wood or anything fancy), a bit of lightweight spackle, and just a bit of sand. I think that if you took the sand out of the mix you would still end up with a nice texture. I stipple it on in thin coats and it leaves a bit of texture without covering up details. Nothing overwhelming but it picks up dry brushing quite well and dries nice and hard.

That said, I have some XPS foam scenery that only has paint and varnish on it. Nothing glued together quite as much as those walls, but they have survived pretty well as-is. No chipping or denting, but I'm fairly careful with my terrain.

[has.been]

Years ago, when our club's Integral Terrain Tiles started to show
severe wear & tear, we thinned down (with tap water) a tub of
flexible ceiling paint. The kind that covers up small cracks in
your ceiling. It is flexible, even when it dries. Thinned down it is
easy to paint on. Use cheap brushes though as it will bugger
them up. Shouldn't obscure detail.

[6mmfan]

Years ago, when our club's Integral Terrain Tiles started to show
severe wear & tear, we thinned down (with tap water) a tub of
flexible ceiling paint. The kind that covers up small cracks in
your ceiling. It is flexible, even when it dries. Thinned down it is
easy to paint on. Use cheap brushes though as it will bugger
them up. Shouldn't obscure detail.

I could try something similar and mix some caulk in with paint. That might give it a flexible rubber coating which won't chip easily.

[Mako]

Modge Podge mixed with paint, 50:50 is the "go to" formula I see on the Foam Facebook Forums.

Looks like it makes them pretty hard without adding much if any weight.

[SotF]

Another thing for toughening it is a relatively light pass with a heat gun...though that's more for rougher looking scenery.

[John Boadle]

The heat gun idea sounds like a disaster in waiting to me!!

The issue here is that whatever you use to toughen the foam will also cause detail and texture to be lost. There is a direct payoff between the two. No substance or mixture can avoid this issue. You have to decide which you value most

Hopefully you have glued the "stones" together reasonably strongly? A narrow base of card or whatever will help the overall structural strength, add a bit of weight and look good if you texture it and add grass and greenery.

A thin coat of most of the substances that have been suggested will help your walls against damage. Personally I wouldn't use anything that has a texture of it's own, because that will lose the nice texture of the foam itself. Doubtless you will be applying a coat or several of paint and that will also add a little to the surface strength.

Blue foam is very popular for making scenic stuff these days, and that's become a niche hobby in itself. It's easy to work with, relatively cheap and you can get nice textures with it, but vulnerability to sharp knocks is an unavoidable downside to the material.

[FreakyFenton]

The german show on Youtube called "Tabletop Workshop" has a whole episode dedicated to this. And much like the people before my post have said, it either comes down to a mix of mod podge, or woodglue or craftglue that you can mix/slightly dilute with water and brush onto your foam pieces. Leave that to dry and then do another pass with a mix of woodglue and a basepaint. If that is dry you can paint it as you want it to look.

However I'm certain a base layer of woodglue/water-mix and then paint can also work.

Hope that helps!

[6mmfan]

Thanks all, modge podge mixed with paint (and thinned) seems like a great idea to try out.

[Daeothar]

Another thing for toughening it is a relatively light pass with a heat gun...though that's more for rougher looking scenery.

Exactly this.

When done carefully, it won't damage the terrain, but it will lightly melt the little bubbles on the surface closed, creating a much more resilient surface.

But I once was in a workshop led by the inimitable Gerard Boom, and I expressed my concern about durability of foam terrain. He then proceeded to throw a completely finished and painted foam tower over his shoulder into the display pieces he had on a side table, which caused absolutely no damage to all pieces involved, while he told us that they were durable as heck.

And now, many years alter, handling my own foam terrain, it turns out they absolutely are...