For a long time I known about Hirst Arts and their molds. By using plaster and other substances once could cast bricks, doors, and other parts to make your own dwarven forge style props for your miniatures. Even complete buildings could be made if you wanted too.
About two years ago Kelly Anne, my wife, got me an inexpensive mold kit, from the science section of a craft store, that allow me to make plaster rocks. Which was useful as props for outdoor encounters in my game. I found I liked doing it but still didn't rush out and get the Hirst Molds as they were expensive ($35 to $45 per) and wasn't sure how durable everything would be.
But then out of the blue, my friend Dwayne of Gamers Closet, got several. I went over to his house to see him casting and came away very impressed. The molds are built to last being made out of a heavy silicone rubber. Definitely worth the premium one paid for them.
So when Kelly Anne was looking for a gift for me this years, I asked for one of the Hirst Arts Molds. I picked #85 Cavern Accessory mold (scroll down to find) as I rarely used the Dwarven Forge props I have (other than the doors) but use the numerous furniture and item props I own a lot.
They take paypal and soon I had my mold in hand. It comes dusted with powder to keep it in good condition when shipping, so per instructions I cleaned it and prepared my first cast. Got some parts out of it but many of the pieces with thin walls broke. Eventually following the excellent tutorials and instructions on the Hirst Art Site. I was able start casting good parts reliably although I still working on getting rid of all the air bubbles.
My brother-in-law is a dental supply technician so I decided to bite the bullet and ordered a box of Die-Keen dental plaster from him. The stuff is like wow, mixes very thin and sets (hardens) very quickly. Plus it is twice as strong as any of the plasters found in the store. Parts still can break but very chip resistant. Air Bubble are still a problem but I am working on that.
I am probably going to pick up #250 Small Brick Mold next so I can build fireplaces and other small stone miniature props.
The above show some of the pieces painted. In this case the sacks of grain/stuff/etc. along with some crates and chests. The pieces up at the top has only been primed but it illustrates that you are not just limited to the obvious choices in the molds. Many of the pieces are in halves or sections so you can combine in interesting ways. Here I glued the stone doors together along with two of the small pillar halves and the lion face to make a shrine to Mitra, the lion goddess of honor and justice.
If the molds have one disadvantage is that the brick molds require a lot of castings to get enough to build even the simplistic projects. Many of the most avid users of Hirst Molds get multiple molds of the same type to speed up production. While other set aside a short period of time daily to setup a casting . After a few days they have enough for their project.
Last you find that you have extra parts that you don't plan on using which makes for a nice surprise gift to you fellow gamers that also use miniatures.