I've spent about a week casting and building with my new Egyptian themed
Hirst Arts molds and have come to some conclusions about them for terrain making. Overall I'm really pleased but have determined these are not always the perfect way to go. No real negatives so I'll break my thoughts into positives and "considerations".
Bear in mind that my casting material of choice was dental stone - which casts up rock hard but is heavy. I think the pyramid weighs close to 5 pounds.
So lets go with the positives:
Positives:
(1) There is a wealth of choice of molds and the supporting materials on the website are top notch. Anything you might like to cast is likely there and the how-to instructions are really very well done.
(2) The details come out very nicely -
if you follow the instructions on mold prep and pouring. The most important part is to pound your fist around the mold as the plaster is poured in, as this releases any air bubbles. I did this for every cast and had very few miscasts (less than 5%). If you want to have detailed carvings or forms in your scenery these molds are probably the best way to go about it.
Considerations:
(1) The molds are small and you'll need to make a lot of casts to finish a project. The 9 level pyramid pictured above required 14 casts of the pyramid mold. Each cast takes about 30 minutes start to finish so it will take a good bit of time to build up your "inventory". Casting is messy so you need to prepare a work area and make sure to clean up as you go along. I did dave all the over pours and used used them to make "gravel".
(2) You need to plan out what you want to build. Most of my terrain projects start with a sheet of Extruded Polystyrene Foam (EPF or "pink/blue foam) and I kind of wing it. The molds construing you to the shapes they form so require a bit more planning than just "winging it"
I really like the Hirst molds but will only use them for "center-piece" terrain constructions. It just takes too much of the hobby time I have to use them for every project. That said, they are well worth the investment and any serious terrain maker should have some in his/her tool kit.