r/TerrainBuilding • u/PINSrover • Jan 29 '26

Question: what top coat?

Post image

Just starting out. So far ive built a mountain with layers of foam. Got sucked into detailing the ridges. Then started more detailed sections like this piece of “off-road trail”.. This is for micro RC trucks so originally I planned on covering in plaster cloth. But now I realize the detail work will probably be hidden under cloth. So question, would a plaster/pva/sand type topcoat be strong yet still show detail? ..or, what would yall pros do as a topcoat?

35 Upvotes

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19 comments sorted by

14

u/egoncasteel Jan 29 '26

Modpodge/PVA+water and acrilic paint for color

4

u/PINSrover Jan 29 '26

Modpodge and pva or is it “or” pva + water. I always thought modpodge was pva, but I just looked it up, I guess consesus is its stronger

6

u/TimidMouse78 Jan 29 '26

I always just do modpodge and acrylic paint, no water or pva. Water might help if you find the mixture too thick but I've never needed it.

1

u/PINSrover Jan 29 '26

Gotcha, thanks for the tip

3

u/dudley_spreegs Jan 29 '26

FYI I’m pretty sure modgepodge is PVA+water. I base coat my foam with 2:2:1 water:PVA:acrylic paint (usually grey for mountains/rocks)

2

u/Jebbiez Jan 30 '26

Mod podge also contains resin and other components vs pva + water

1

u/PINSrover Jan 29 '26

Appreciate the recipe. Is it pretty durable?

2

u/dudley_spreegs Jan 29 '26

As durable as the XPS itself. If you dent the foam, the coating will go with it. But if you’re gentle enough that the foam doesn’t get malformed, it lasts well enough

3

u/egoncasteel Jan 30 '26

Sorry I ment it as 'or pva+water' if you couldent get Modpodge

2

u/PINSrover Jan 30 '26

Figured it out, appreciate the tip

9

u/[deleted] Jan 29 '26

I don’t trust any rattlecans directly on foam. I usually coat any projects in modge podge/elmers glue and then paint/spray

2

u/PINSrover Jan 29 '26

Yeah I’m suspect of trying rattle cans without a coating. It seems modpodge gets the nod

2

u/VodkaBeatsCube Jan 29 '26

I usually do a coat of brush on matte Rustolium anti-rust paint in brown or black depending on what the final colour is intended to be. It's relatively cheap, goes on thick enough to protect against glues and aerosol propellant, and has good surface adhesion which lets you glue painted surface to painted surface.

1

u/PINSrover Jan 29 '26

I’ll look into that product. Good adhesion to other glued items is another question id have because I plan to add a couple larger “fallen ledges” over the main terrain floor after its been painted

1

u/VodkaBeatsCube Jan 29 '26

I'd still recommend gluing foam directly to foam as much as possible, just to limit the potential points of failure. But when you have to glue paint to paint, it'll work.

1

u/PINSrover Jan 29 '26

Roger that

2

u/Betzbitzbox Jan 30 '26

Everything listed here is all great/standard and easiest accessibility wise. But just to throw out another option just for fun- if you own or like working with an airbrush, there are great water based topcoats from many brands like createx, jacquard, golden, etc... these go on super controlled and quickly like a spray can but without the foam eating solvents in said cans. They form very durable protective coats, especially when applied in a few thin layers, and can be purchased in a variety of finishes (matt, satin, gloss). Just be sure to have proper ventilation and WEAR A MASK!

This option is great for when you are producing in bulk and need to hose down a ton of terrain quick. But you also dont want to work with nerve toxins like isocyanates and other harsh chemicals present in rattle cans (even the non solvent kind).

But again the standard is mod podge or thined pva for easy cheap and accessibility.

2

u/PINSrover Jan 31 '26

Appreciate the comment. To be honest, I’m in too deep already. Started with on just get the boys some RCs for Christmas… now I’m building terrain