Yes, I’ll probably still use some Mod Podge for some of my terrain but I think I may have found some thing that makes the pieces more resilient.
This all came about because of failed experiment on my Dungeon Stackers. I tried some thing that didn’t work but I did notice that they felt tougher than the other pieces that I had made. And here’s my secret sauce so to speak. Minwax Polyshades Classic Black. If you dig thru the Internet some folks are using Minwax Polyshades Antique Walnut as cheaper alternative to Army Painter Strong Tone. And in case you are wondering, the Polyshades line of products is stain combined with polyurethane.
Let’s get this party started with some warnings. This stuff is oil based so that means you need mineral spirits to clean up. Also, it means fumes. So use in a well ventilated area.
For prep of the foam, I used my standard techniques. Cut out the shape, run some fine grit sand paper over it and the texture as usual. Now, we coat it. First and foremost, use THIN coats. This is very important. After a couple of hours of dry time, you’ll notice some patches that the stain has totally penetrated the foam and you can the color of the foam. Once again, THIN coats! to cover. You can easily tell as it dries that your coat was too heavy. You can see it on the shiny patch on the left side. The polyurethane will “pool” on the surface. Since I used gloss this created a smooth, shiny area that also obscured some of the detail.
The whole idea behind the Mod Podge was to be a first layer protection for the foam. And to protect it from the propellants if you’re using spray-on polyurethane which will eat the foam. This is brush-on so no propellants but as I said there are fumes. The Polyshades give a stronger and more durable base coat than the Mod Podge. I’ve also found that the stain penetrates and covers any nooks and crannies of the piece better. Remember THIN coats. While XPS isn’t porous, it’s still foam and has pores.
Next up, you want the piece to dry. Better yet. You want it to cure. So what’s the difference? Dry means you handle it and add another coat. Cure means that all of the chemical reactions are done and the polyurethane has reached final, maximum durability. Based on my Internet research this will take about a month under average conditions. The two key elements for the duration of curing time are temperature and humidity. DO NOT use your oven, heat gun or something like that. It’s too hot. I wouldn’t leave it my car in the sun. It might get too hot and will stink up your car. For this bit of UDT, I just left in the un-air conditioned garage. Yeah, I’m in Texas so it’s topped triple digit temperature and where I am, it’s not that humid. I let this piece hang out in the garage for a week.
Let the painting begin! Hey wait! Can you use acrylic craft paints on polyurethane? Yes you can! This time, I did a cobble stone pattern and instead of base coat, I painted each stone then dry brushed over that, then a black wash, and another very light pass of dry brushing. Then a couple coats of Minwax Polycrylic for the final layer of protection. And here’s the finished product.
And you’ll notice that I’m also doing another UDT piece. This one is slightly smaller at 12 inches in diameter without zones. This is my piece for big rooms. And I know. I can’t cut a circle to save my life.
Am I going to do this for everything that I make out of foam? Probably not. It just depends. If it’s something that is going to see a lot of use and wear and tear then sure the extra time for some extra durability is worth it in my opinion. And of course, YMMV.