"6-in Hex Tiles Casting Plaster" Topic

I'm looking to cost effectively cast hexes only 1/2 an inch thick.

The shallow gravity molds I am using are for cement and plaster garden tiles. They are heavy plastic.

My initial thought was to use products I have used before…

3 parts Durham's Rock Hard
1 part sawdust
a few tablespoons of powdered tempura

As I plan on filling a 4 ft by 8 ft table with hex terrain, cost prevents things like resin or latex from being used.

Ideally, I would prefer to color the casting material in the event of chipping over time. I also have a source to make brown dye from black walnuts rather than tempura. Very traditional, but it works.

Does anyone have alternate suggestions? I would welcome any advice.

Thanks,
Robert

Not so much on the plaster – but I do something that is similar.

I had a company laser cut a handful of hexagons out of 1/4" acrylic. I then take the rigid foam insulation and use carpet tape to stick the acrylic hexagons to the foam. On my table saw – I use a pattern cutting fence (allows the hexagon to run in line with the blade) to slice the foam up.

link

I can do around 40 square feet an hour with 10" hexagons. Lighter and faster than most other things…cheap as dirt too (a 4x8 sheet of insulation gives me 32 squares with a bit of waste for around $10-20 depending on thickness).

The 1/2" plaster I would be afraid to let anyone touch. While it is strong enough – I can just envision someone dropping a stack of them when putting them away or getting them out.

You might consider switching out the sawdust for something like loose fiberglass (body shops sell it for doing fiberglass fillets on automotive and boat bodies). Mix that in to give it a bit more strength in shear.

I considered doing this sort of thing (although I was planning on making my own molds from masters I had 3D printed). In the end, though the numbers could not be manipulated enough to make it more cost effective than having foam hexes cut for me. Of course, I'm looking to make geomorphic hills, rivers, roads, etc. so I could be considering a lot more tiles than you are.

If you want to make them damn near indestructable, you might consider the Merlin's Magic or Excalibur casting plasters. My wife and I use the MM for casting Hirst Arts blocks and it is incredibly tough – Excalibur is reputedly even harder (albeit a bit less forgiving).

They're going to be awfully heavy, of course.

Doug

Paper mache would be lighter.

But more fragile. Probably sufficiently strong for most purposes, though.

I'd be interested, by the way, in where the hex molds came from.

Doug

You can cut up pieces of wire hardware fabric and embed those inside each hex. That wouldn't stop chipping, but would make it more resistant to breaking across the middle.

You might also consider quikcrete. There is a version that is very fine and mixes with water to the consistency of pancake batter, which should be fine for purposes of filling out to the corners. Just be sure to spray the mold with WD-40 or another release agent, though, or else the quikcrete might not want to let go.

I have some I've been working on for the last few weeks. I didn't care for the hex tile molds, as they didn't join up well over large areas so I had forms laser cut to make my masters from. Each hex has a ground level of 3/8", and is 6" from side to side. I'm casting them in silicon molds using an encapsulation technique. Resin holds the detail in the surface of the piece while the bulk is filled out by a separate filler. My first few attempts worked but didn't quite fit the bill (foam was too time consuming, foam core vented air into the resin marring the underside, etc…). My current test pieces are using a cast Hydrocal core and a special closed cell foam…so far the closed cell foam looks the most promising as it isn't venting, it is light but durable (without the impact problems of the hydrocal core) and I can get the cost of each core down to just $0.40 USD without making a large purchase.

I'll show off what I've managed to get done next month. The hex tiles are the bases for my 15mm Kobold Village.

@ScoutII
Fiberglass…good idea.

@elsyrsyn
Merlin's Magic looks promising as does the Excalibur. MM can be pre-colored. As I have experience only with Durham's Rock Hard, is the advantage over DRH compressive strength and cost?
moldwarehouse.com

@Editor
Oddly, I've never used paper mâché. Will it cast that thin (1/2")?

@javelin98
Excellent suggestion with the mesh. Is WD-40 safe on a plastic mold?

@Paintbeast
I look forward to seeing your results.

@elsyrsyn
Merlin's Magic looks promising as does the Excalibur. MM can be pre-colored. As I have experience only with Durham's Rock Hard, is the advantage over DRH compressive strength and cost?
moldwarehouse.com </q?

I don't know the strength stats for Durham's, and I've only used it a little and that a good while ago. From what I can recall, however, the dental type plasters are stronger. I also don't know what Durham's runs these days, but from Clint Sales, I get 50# of MM for about $75 USD (including shipping, which is naturally expensive).

That's a pretty cool mold site – thanks. One thing about the hexes from those molds, though – the edges are filleted on one face. You would not have that issue with cnc wire cut foam hexes. You'll also be surprised how cheap they can be (if bought in large numbers). Finally, once you have your blanks, you can cut all sorts of shapes with a hot wire cutter – you'll not be able to do that with plaster. Can you tell I'm sold on foam?

so far the closed cell foam looks the most promising as it isn't venting, it is light but durable (without the impact problems of the hydrocal core) and I can get the cost of each core down to just $0.40 USD USD without making a large purchase.

The problem I had with poured foam was the time factor – most of the kinds I looked into had pretty significant set times, which meant I would need a pretty significant number of molds to make any headway.

Doug

Excellent suggestion with the mesh. Is WD-40 safe on a plastic mold?

Most the time – however, as with any chemicals…always test on a spot that is out of the way to make sure (little squirt on the outside of the mold will let you see if there is a reaction without having to worry about the mold being damaged itself). While I don't ever recall seeing a reaction from WD-40 with…well, pretty much anything – it doesn't mean that one won't happen with some odd-ball plastic formulation.

From what I can recall, however, the dental type plasters are stronger. I also don't know what Durham's runs these days, but from Clint Sales, I get 50# of MM for about $75 USD USD (including shipping, which is naturally expensive).

You might also call around to local hardware stores. Seems a bit odd – but that is wear I get the dental plaster from that I use. Cheaper than most of the online sources right away – plus you don't get hit with the shipping charges (which if you are going to be doing a significant number of tiles will really add up).

The shipping on the dental plaster does stink. I spent a day earlier this week trying to find a dental supply house locally that stocked it (or something similar – Garreco's Tecstone FL looks promising, for example) with no luck. They either will not sell to individuals, or their prices seem to already include the shipping. I'd not thought to try a hardware store – thanks for the tip!

Doug

"The problem I had with poured foam was the time factor -"

Oh, sorry…I counted any sort of expanding foam out from the start. I use that for my larger items but it is just too much of a bother for anything as small as a 6" hex (that is only 3/8" thick). I was testing a type of sheet foam, High Impact Foam. It is black and very dense with a closed cell structure for absorbing impacts. It is popular among stunt men and comedians. I'm scrapping it from my list of possible cores though.

Ahhh – I think I know the material. I've used it, or somethng very similar, to make helmet padding/liners for SCA fighting. It was fairly expensive when I bought it, but that was in a very small quantity from a reseller.

Doug

I've poured concrete stepping stones in plastic molds for my wife using WD-40, with no problems. However, you could also use Pam cooking spray, which is biodegradable as well. As an added bonus, your terrain may come out smelling somewhat like buttered popcorn for a while!

A good distributor of dental plaster is Whip-Mix, and they'll send you a free sample if you go to their website and ask. Good strong stuff.

Thanks for both suggestions javelin98.

I wound up using Bill's suggestion…a mix of shredded paper insulation, cooking flour, vinegar and wallpaper paste. They dry light and hard. Cheap to make. Only down side is the cure time, but only plaster will do better there.