Rocky Road: How to Make Cavern Floors
D&D, Dungeons & Dragons, Hirst Arts, Home Brew, Terrain Add commentsSteadfast at the helm of his mighty terrain ship, Captain Ben stares sternly into the eyes of the great White Whale. The time has come for this mighty beast of intimidation to be dealt with directly and decisively. No longer shall his Hirst Arts cavern floors scour the seas of disappointment. Avast Ye Maties! It’s time for a showdown of mythical proportions – let’s show these tiles who’s boss.
One Idea to Rule Them All
Back in October, Ben’s inspiration journal contained an absolutely stunning cavern game table from Gen Con. The builder’s out-of-the-box treatment of the floors was just brilliant. Ben was officially inspired. So much so, he spent the next four months gathering, researching, testing and mustering up the courage to create a similar set up for his own campaign.
And while an exceptional tutorial from Hirst Arts forum poster “Bumyong” gave Ben the new walls he desired, those pesky cavern floors remained elusive.
The aha moment came when Ben took Bumyong’s paint scheme and combined it with his Gen Con Polaroids (that’s old man speak for “photos”). He finally had an actual map to navigate the treacherous open waters. Even better – the RPG community made a fine first mate by giving him critical pointers along the voyage.
So, without further ado, here’s how to make a great Hirst Arts cavern floor. Let’s stick with this buccaneer theme since everything is better with pirates.
Set Sail
For casting purposes, the cavern floor only requires two molds:
- Cavern Floor Mold #281
- Cavern Floor Accessories #282
Our floor technique is going to allow for a wide-eyed imagination of tile configurations without ever worrying about how those gaps will look.
Batten Down the Hatches
Your first key ingredient comes courtesy of a fellow gamer (Zoe) who suggested filling in those empty spaces with a common spackle material: specifically DAP Fast N Final Interior and Exterior Spackle. You can snag a one-quart tub of this whip-cream-like-substance for under $10.
This material choice was epic! Ben previously tried using the Vallejo products and Bruce’s dug up earth tip but those were a disaster for his skill level. Vallejo was insanely hard to apply in tight spaces while the HA idea required some mixology that Ben just couldn’t master (and it was really messy).
The spackle is super easy to use (just smooth on with your finger) and fills in the cracks perfectly with very little mess. It was a match made in heaven.
Once the spackle material has dried (which takes no time at all), you will want to lower the filler lines. Ben used a Norton Multisand Very Fine sanding sponge for this step ($2-ish). Just run your sander in the crevices to create a small trough. This TLC step ensures our flock application will go off without a hitch. Your newly spackled piece should look like this.
Swab the Deck
This painting step gave Ben a wretched case of sea sickness. All his color tests were dreadful. Thankfully, Bumyong’s paint scheme combined with the spackle filler and flock application got Ben the end result he wanted.
So here are the simple floor paint steps (after the spackle has been applied):
- Prime with Valspar Satin Brown Velvet (85044)
- Apply a heavier dry brush of Walmart’s ColorPace brown blend
- Use a lighter dry brush of Americana’s Toffee
- Your painted piece should look like this
The ColorPace paint step is not a base coat. You purposely want some darker spots to come through. Ben has always been a one dry brush and out kinda guy so these simple brush applications fit nicely with his energy comfort level.
Splice the Mainbrace
Now we’re going to make our floor tile truly sing by emulating that soul-soothing flock technique from Gen Con. Your previous spackle and sanding steps make this step finger snap task.
To ensure success, we’re going to pull one more hobby weapon from our belt to ensure this flock application goes well. And once again, the RPG community saves the day. RubbishInRubbishOut encouraged Ben to always have a pre-mixed bottle of PVA glue on hand (60% Elmers Glue and 40% water). AwesomePaintJob recommended the perfect bottle to hold and apply your liquid concoction. You want a small squeeze bottle with a fine point and a cap that seals tightly. Ben picked a three-pack of Americana bottles at Hobby Lobby for $3.
So here’s what you do next:
- Use your squeeze bottle to fill the crevices with your liquid PVA
- Pop any big air bubbles with a toothpick
- Pour a very fine sand flock all over the piece
- Wait about 2 minutes for the flock to bond
- Shake off the excess
- Gently push down any raised sand spots so its smooth and level
- Your flocked piece should look like this
A very fine sand flock is a critical material here. Haphazardly taking a cup from your child’s sandbox is ultimately going to be too thick and clumpy. Ben fell in love with Skullcrafts’ Oregon Beach sand flock but alas it’s no longer available. No worries – you can always use oceanfront sand (or have a coastal buddy send you a jar). To play it safe, just put that beach sand through a strainer to ensure its granular enough. A couple Pile crewmates harvested/sent Ben two types of beach sand: San Diego and Florida. The San Diego was a near perfect match to Skullcrafts. Florida was heavier on the shell side and lighter in color.
You can even get creative and do a two-stage flock here. First do some scattered spots of green moss. Once dry, go back and fill the rest in with your sand. It’s a nice effect.
Thar She Blows
Finally, you’re going to want to seal in the goodness with Krylon Low Odor Clear Finish ($6). Not only does this spray cement the flock down, it also darkens it up a smidge to really bring that dirt feel home.
Yo Ho Ho
Now we can do a legitimate before and after shot of our cavern environment. Ben is extra happy with the results. The spackle filler also allows for a slew of new cavern floor stone configurations and the not the same old square 3×3 layout routine. The combination of the sand and smaller tiles also makes d20 square identification a snap.
As Ben’s game group prepares to enter the Pyramid of Shadows, he’s now able to add a second level of underground mystery and danger. Thankfully, he finally has the cavern floor tiles to back it up.
Next week? Well, we gotta make some big cool rock pieces to go with these new floors, right?
Questions to Ponder: What do you think of the new cavern layout? Does dirty sand beat green rock gaps? Do you have a lot of your RPG games take place underground? How often do you stray from a module’s setting? Did you know what all the pirate phrases meant?
Interact with Fellow Hobbyists Daily on Our Facebook Page


February 23rd, 2013 at 10:44 am
I started painting the cavern walls yesterday with a test piece. Came out good enough to use but I can still improve. Now with this I am ready to rock and roll. Thanks Ben.
February 24th, 2013 at 1:27 pm
Hey that’s great to hear! Bravo for doing a test piece and not rushing into it. Looking forward to learning more about your work. Consider posting in the Hirst Arts picture forum so others can see your efforts.
http://hirstarts.yuku.com/forums/4#.USp3plojpoI
February 25th, 2013 at 9:47 am
I have some of these cast and have yet to work on my cavern set but as cool as this is, I feel like you lose something in the gaps when you fill it in. So here was my thought, to create variety have a set that is sandy and with filled in gaps.
The other set, here is the idea I was going to work on, complete casting and tiling. Then make a mold to set the tiles in, and then poor in either resign or scenic water into the gaps so the floor is like rocks breaking the surface of a watery cave system.
http://static.howstuffworks.com/gif/stalactite-stalagmite-1.jpg
February 26th, 2013 at 10:47 am
How could you do this to me?!? Those flocked floors were amazing!! I was perfectly fine with gapped floors until I saw this! Now I will have to redo my hirst floors AND my own homemade reinforced foam tiles. I stopped making hirst tiles because of the weight limit of my shelf space but have literally 30 square feet of my foam tiles (I just counted) plus hallway tiles. My group binges at 8 hours of gaming at a time (two or three times a month/as my wife allows), so some of my terrain set ups get pretty large (plus the different type of floors).
To get this done I will have to sneak out of bed in the middle of the night for the next month!
February 26th, 2013 at 12:12 pm
Aren’t they great?! I just love ‘em. Wait till you see this Saturday’s post (when I integrate some foam into the new cavern scheme).
Hah! We have similar play schedules and women (but we only get in one game a month).
Just tell your wife that you’re having a little heartburn and that she should go back to bed;)
February 26th, 2013 at 7:26 pm
Ha! I get a little leeway. I play with two of my godsons (30 and 18 years old) and three of my kids (13, 10 and 5 – the 5 year-old plays the wolf animal companion of the 10 year old so the intelligence works out perfectly).
It is a different game from DnD as I have to keep it kid safe and appropriate for a christian audience (I am also a youth pastor). So I work in life lessons and keep out evil alignments & all deities. But I stay as true to the game as I can.
The terrain is a way for me to keep the younger ones focused during heavier role playing. But as you know, guys like us never grow up and we love the 3D terrain as well.
Can wait to see what you do with the foam!
February 27th, 2013 at 5:58 pm
Hey Ben my name is Anthony and I am studying digital animation I am on my second year and I have a great idea for D&D its an idea/business opportunity and I would like to hear your thoughts on it. how ever I am reluctant to share it openly on the forum do you have a work email I can write too?
cheers
February 27th, 2013 at 10:04 pm
Hi Anthony,
Neat! Any D&D idea is a good idea;) The easiest way to PM me is to fan our Facebook page (bit.ly/facebookrpg) and then shoot me a private message. Happy to share feedback with you.
Side Note: Bravo for making an excellent career choice. Your services after graduation will be in great demand. Work extremely hard and pile on those semester internships.
Thanks,
Ben
February 27th, 2013 at 10:08 pm
Hi Mark,
Your comment was so great to read. That game group sounds perfect! I absolutely believe D&D can be played in an enjoyable way (based on your family environment description). I applaud you for your work.
We’ve put on D&D dungeon delves at conventions with full 3D game boards and have seen first hand the wonderment of the youngest D&D generations. It warms our soul when we play and teach them the game.
Oh I got some tricks up my sleeve with the foam. The tutorials will make it a snap for you to try for your own game. Your group will be quite pleased with what’s to come.
Thank you so much for your note. You made my week.
Ben
March 8th, 2013 at 3:22 pm
I dig what you’re laying down, Blair. My mold making skills are really raw right now (although we’re testing out some stuff this Saturday). You go first and show us how it’s done;)
March 19th, 2013 at 8:45 am
Hey Ben,
Love the sand flock and I too noticed the same board you did at Gencon. Question: Does it look ok that there are gaps where two floor pieces meet? Does it look unsightly at all? I’m wondering whether I should do mostly larger floor pieces to cut down on that. Thoughts?
March 19th, 2013 at 9:05 am
Hi Greg,
Excellent question, my friend.
Yep – there are a few gaps here and there. The reason is that I had some rounded corner Hirst blocks on the outside edges and that makes it harder for connecting modular tiles to be flush with one another.
Larger based pieces definitely solves that issue. That’s what the guy at Gen Con did (he had big ol’ square sections).
I’m actually insanely modular in my builds so I don’t really mind the gaps here and there. The way I plan to solve is by putting the tiles on top of a black cloth. That way any gaps will just look like darkness. When that black is underneath, the 3D game board looks really good.
What I really like most about the sand pieces is that each tile can be laid out very, very differently.
March 19th, 2013 at 1:57 pm
Thanks for getting back to me, really appreciate it.
I’m casting my cavern pieces right now and slowly gathering the different paints. I’m hopeful to give this a go using your tutorial. I’ll need to find good sand flock and make a call on the color of the cavern rivers vis a vis the brown cavern aesthetic. Olive green perhaps?
March 20th, 2013 at 2:42 pm
Hey Greg,
Your color instincts are correct. Try painting the open water grooves GW Knarloc Green/Loren Green. It looks really good. I have an example in the 3/9 Super Market Saturday post blog entry.
My pleasure to offer a helping hand. So glad you like this tutorial.
Ben
March 29th, 2013 at 8:13 pm
Have you ever thought about creating an e-book or guest authoring on other sites? I have a blog based on the same information you discuss and would love to have you share some stories/information. I know my readers would value your work. If you are even remotely interested, feel free to send me an email.
April 6th, 2013 at 10:22 pm
I actually have guest authored on several fine RPG sites. Very proud of the tag teamed work we did for each article.
I’ve pondered an ebook but our current terrain project/possible kickstarter is absorbing our time. You can always drop us a line on our Facebook Fan page: bit.ly/facebookrpg