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Hey guys, I recently discovered Hirst arts as a thing thanks to reddit, and I have been obsessing about it all day. Does anyone have any advice for someone looking to get into it? I would love to start building towers and a Roman temple for my next army on parade project. I think I would get merlin’s Magic plaster first, and read most of the tutorials, but I want more information before I start building.

How difficult is the whole process?

It's as difficult as knowing how to mix plaster (or resin, the moulds can be used for that, as well ... ). This includes quantities to mix (small batches, since it gets hot when mixed, and the more you mix, the hotter it gets, and the faster it goes off).

You need a few tools (measuring cups, a nice mixing spatula, some steel rulers (For scraping down the excess BEFORE IT SETS) and something to mix it in, a nice flat AND LEVEL surface and patience.

also, a fruit dehydrator can be useful.

 chromedog wrote:
It's as difficult as knowing how to mix plaster (or resin, the moulds can be used for that, as well ... ). This includes quantities to mix (small batches, since it gets hot when mixed, and the more you mix, the hotter it gets, and the faster it goes off).

You need a few tools (measuring cups, a nice mixing spatula, some steel rulers (For scraping down the excess BEFORE IT SETS) and something to mix it in, a nice flat AND LEVEL surface and patience.

Okay, sounds good for those. How is it building the things according to instructions? Or building it free form?

Also, Which molds do you recommend buying first?

I found the wizards tower is not a bad one to start with, then the basic dungeon one, a floor tile one and a roof slate one.

they are fun, its like Lego that you never run out of. I did however find resin much better than plaster if you want to move stuff, plastic is heavy and not as strong.

pick the "gothic" or the "fieldstone" theme to start with, they are probably the most flexible

warning: this stuff is addictive


also get a few cheap oven baking trays, not for baking the blocks on, but somewhere to dry them - a decent building will need about 20 odd castings, with plaster this takes an age

leopard wrote:
I found the wizards tower is not a bad one to start with, then the basic dungeon one, a floor tile one and a roof slate one.

they are fun, its like Lego that you never run out of. I did however find resin much better than plaster if you want to move stuff, plastic is heavy and not as strong.

pick the "gothic" or the "fieldstone" theme to start with, they are probably the most flexible

warning: this stuff is addictive


also get a few cheap oven baking trays, not for baking the blocks on, but somewhere to dry them - a decent building will need about 20 odd castings, with plaster this takes an age

I got the Roman temple mold, and planning on trying it out tomorrow before I get my surfactant in the mail. I can already tell this is going to be addictive, but thanks for the warning. Do you suggest baking the concrete blocks in an oven? Or just leaving them out to dry? And I plan on getting the wizard’s tower mold and turret mold next. I think i’m Going to stay away from field stone just because I am planning on elven buildings.

Also, got about 5 pounds of Merlin magic stone for this, so I hope it goes well!

 Tiger9gamer wrote:
Do you suggest baking the concrete blocks in an oven? Or just leaving them out to dry?

I wouldn't bake them. If you're thinking about the baking tray suggestion, it was just for an easy way to carry/store a few molds while keeping them flat - a cutting board or sheet of plywood/MDF would serve just as well. Some people like to use food dehydrators to speed up the process (once the pieces have firmed up enough to de-mold but aren't fully dry - they'll still feel cool to the touch), but that's comparatively low heat and high airflow, compared to a conventional electric/gas oven.

When I looked into the topic some years ago, there were plenty of articles around the web (including many on the HirstArts site) detailing the process, with various tips and tricks. The biggest takeaway was to be patient. If you aren't, you need a LOT of molds and a LOT of space to do big production runs of parts. You'll likely spend more time casting than building... and you'll spend much more than either just waiting for pieces to cure.

yeah I just put the bricks on baking trays as they are non stick and waterproof.

I did find we had a double radiator they would sit on top of that warmed them and helped them dry. the plaster "sets" pretty quick, its just removing excess moisture after that

its worth having a look at making your own moulds if you get into this, specifically to make larger ones for basic bricks, in singles and multiples to cut the time down.

plus you quickly get a feel for how much plaster to mix, one hint I found was if you plan to fill two moulds, have a third ready as the dregs can usually fill or ot two blocks from that.

plus prop one up at a slight angle (baking trays are vey good for that, and catching overspill) and you can get some part filled angled blocks that are good for terrain and basing

I find having a box to put miscasts in helps a lot as well, good for breaking up as 'rubble'

I think the wizards tower is something like 20-25 runs to have the blocks you want so this does take an age.

that Roman one looks good but isn't terribly flexible, good for rectangular ruined temples though

 oadie wrote:

 Tiger9gamer wrote:
Do you suggest baking the concrete blocks in an oven? Or just leaving them out to dry?

I wouldn't bake them. If you're thinking about the baking tray suggestion, it was just for an easy way to carry/store a few molds while keeping them flat - a cutting board or sheet of plywood/MDF would serve just as well. Some people like to use food dehydrators to speed up the process (once the pieces have firmed up enough to de-mold but aren't fully dry - they'll still feel cool to the touch), but that's comparatively low heat and high airflow, compared to a conventional electric/gas oven.

When I looked into the topic some years ago, there were plenty of articles around the web (including many on the HirstArts site) detailing the process, with various tips and tricks. The biggest takeaway was to be patient. If you aren't, you need a LOT of molds and a LOT of space to do big production runs of parts. You'll likely spend more time casting than building... and you'll spend much more than either just waiting for pieces to cure.

Can do on working on my patients. I can only afford one mold for now, so I will have plenty of time to wait.

@ Leopard: thanks for the tips! I may just have a miscast box later on. I did my first two attempts today and I can already tell I need a more level surface, and I really need to learn how to mix the plaster in the proper amount. I am enjoying this so far, even if I did get a lungfull of dust on my first casting.

another question I got is about letting it dry. I kept it in the open all night, but I can't tell if the blocks are just cold because it's stone or because it's still trying to dehydrate.

Leaving any production of molds overnight in a dry part of your place will get them dry enough, two if you really think that you need it, but I rarely needed it. Usually when they are still moist they have a two tone of the color that you are molding them with. When they are one tone of the color that you mold them, they generally are dry enough to use them. I have done the baking idea, and really did not see much of a difference between that and just letting them dry overnight. They both ended looking the same.

My best tip is to watch how much you pour with Merlins Magic. It takes some time to know how much you really need for a pour. I have a tendency to use too much Merlins and get too many bubbles that I don't want.

TinyLegions wrote:
Leaving any production of molds overnight in a dry part of your place will get them dry enough, two if you really think that you need it, but I rarely needed it. Usually when they are still moist they have a two tone of the color that you are molding them with. When they are one tone of the color that you mold them, they generally are dry enough to use them. I have done the baking idea, and really did not see much of a difference between that and just letting them dry overnight. They both ended looking the same.

My best tip is to watch how much you pour with Merlins Magic. It takes some time to know how much you really need for a pour. I have a tendency to use too much Merlins and get too many bubbles that I don't want.

yea i'm getting the bubbles a lot. do you know the ratio of Merlin's magic to water? I try to judge it by how thick the mixture gets, but since it's a flow stone it takes a lot of powder before I can tell if it's good or not.

 Tiger9gamer wrote:

TinyLegions wrote:
Leaving any production of molds overnight in a dry part of your place will get them dry enough, two if you really think that you need it, but I rarely needed it. Usually when they are still moist they have a two tone of the color that you are molding them with. When they are one tone of the color that you mold them, they generally are dry enough to use them. I have done the baking idea, and really did not see much of a difference between that and just letting them dry overnight. They both ended looking the same.

My best tip is to watch how much you pour with Merlins Magic. It takes some time to know how much you really need for a pour. I have a tendency to use too much Merlins and get too many bubbles that I don't want.

yea i'm getting the bubbles a lot. do you know the ratio of Merlin's magic to water? I try to judge it by how thick the mixture gets, but since it's a flow stone it takes a lot of powder before I can tell if it's good or not.

Bruce has some good directions on his website for Merlin's Magic. I use his method where you mark the lines on a side of a disposable plastic cup. The hard part for me is that I have a tendency to fill in powder on the sides of the cup that I am making the mixture in. I think that this is what allows me to use too much of it. You can tap the side of the cup to let the powder settle more which allows me to use more powder, which gives me more bubbles. These are micro bubbles that I am talking about, not very large ones, but on special casts where you need smooth casting, this is a problem. When he talks about keeping thinning the mixture thin, this is what he is talking about. Likewise I have also notice that the thicker the mixture the more "grainy" the mixture will be at the bottom.

Another issue that I have is that I tend to see bubbles spring up when I stop pouring a bloc. The bubbles seem to congregate where I stop and start again, so I tend to be one of those who recommend pouring as much as you can to fill the section that you are on and then move one to the rest of your mold.