Syringes and casting joy…

OK, so after casting ten of each of the fieldstone bridge and castle tower molds, I noticed that as careful as I had tried to be, I still had a few pieces with minor bubble problems. Nothing to be concerned about, I hope, but it still annoys me that I could be that careful and still have bubbles. Also I was getting tired of the mess.

The way Hirst suggests that you fill your molds is to pour a thin stream of plaster on the edge of the mold cavity (usually between a couple of cavities) and allow the plaster to slowly flow down the side and then to fill in the entire cavity from the bottom up. Then, without stopping the stream, move to another edge and do the same until all the cavities are filled. This will end up with some extra plaster on the top of the mold, but you will scrape that off after it sets a bit so that you end up with a completely flat “top” (which is usually actually the bottom) of the molded piece. You do end up “wasting” some plaster since you are pretty much pouring plaster all over the mold until it overflows each cavity and with the trails of the flow as you move it around, you end up with pretty much the whole mold covered in a puddle of plaster. When you scrape the excess plaster off, you leave a huge puddle on your work surface. I have been scooping that up and tossing it into one of my big column molds so that it isn’t wasted, and as a result I’m getting close to having 30 columns now, almost enough to do a replica of the Parthenon…

But the thing is, getting that smooth, perfect, thin flow of plaster going is hard enough in the first place. Keeping it going four an entire pour is extremely difficult. The dudes on the instruction videos make it seem so simple, and I suppose it is if you pour molds for several hours every day like they probably do. But in my case I get burps and blops and surges and times when the plaster curls under the rim of my plastic cup and starts to crawl down the cup on my fingers, dripping all over creation….

So… last night, after laying out all the items and seeing that some of them had bubbles in spite of my best efforts, and looking around my room and seeing all the excess plaster all over the place, I decided there had to be a better way.

It turns out that a long time ago I bought a fairly expensive guitar humidifier device. It is a little plastic doodad with a sponge inside and you fill the sponge up with water and place the device between your guitar strings so that it hangs into the guitar’s body cavity. There it will slowly moisturize the guitar. To fill the device it came with a syringe about the size of my index finger and about as big around as my thumb. The syringe has an open plastic nozzle and it looked to me like it would be perfect for plaster.

But what about my guitar? Well, I don’t use that humidifier anymore since one of my guitar expert friends informed me that they are the least effective humidifiers (in spite of being by far the most expensive I saw), and I now use a plastic circular humidifier which fits snugly in the guitar hole and essentially seals in the moisture so that it has nowhere to go but into the guitar body. So the syringe was just laying around…

So this morning I whipped up a batch of dental plaster and used the syringe to fill up the cavities.

OMG! This is so NICE! And NEAT! I have almost total control of where the plaster goes, the speed it flows and there is no trail of plaster as I move from cavity to cavity. I fill up just what is needed with just enough excess so that I can offset the settling that occurs with the dental plaster I’m using, and I ended up with no more than a teaspoon or so of excess plaster, which I put into the column mold.

But the proof of the experiment isn’t whether it is neat, it’s whether it defeated the bubble problem.

It’s only one cast, but every single item, even the most intricate and tiny one which was the most difficult to fill with the “pour it from a cup” method, all came out downright perfect.

I did have to use a bit of extra water to clean out the plaster from inside the syringe before it cured, but that’s not any problem.

The one thing I wish is that the syringe had a longer and curved nozzle. And guess what? They sell exactly that at pharmacies. So I’m going to pick up a few today.

I’m quite pleased with the results of this little experiment. Neater, faster, virtually no cleanup and most importantly… NO BUBBLES!!


First 10 castings from Hirst molds

Here’s a horrible pic of the fruits of my casting labors today…

The blocks on the far left may look like rectangular blocks but that’s because I have them on edge to allow more to fit on the drying board. They are actually arcs. I’ve set several other blocks up on one edge to save space as well. The left half is the tower, the right half is the bridge (actually it’s more like the left 40% is the tower and the right 60% is the bridge, but who cares…)

Lots of blocks…

Yet another plaster conundrum…

So… I have the two molds I posted about below… And now I’ve done ten casts out of each mold. I’m taking a break to let them dry.

It’s not as much effort to do all the casting as you might think. It’s time consuming and messy, but not all that much work. The largest chunk of time is the mixing and pouring of the plaster (which is also the messiest chunk.) It probably takes between five and ten minutes to do that, depending on how efficient I am. Demolding the cured plaster items just takes a minute or so, you just pop them out. So the overall effort to cast ten copies of two molds was probably something on the order of an hour of work, with maybe six hours of waiting for the items to cure. But during that waiting I was working, walking the dog, eating, etc…

So not a whole lot of work invested.

So far.

Of course I still have to paint them and assemble them. There’s no way for me to know how long it will take to assemble something. And I have to wait at least 24 hours for them to dry. Probably should wait 48 hours since we keep the house fairly cool in winter. Maybe I’ll run a heater in here tonight…

Once they are dry I have a decision to make. That decision is “Should I assemble and paint the bridge, or should I create a custom mold from a few key blocks that I could use to build more things more quickly than using the bridge mold?”

See, the thing is that the bridge mold has some blocks that are identical to some of the blocks in other molds for building walls and steps. Since I had to cast ten copies, I’ve got at least ten copies of every block in the set, so I could make a custom mold that had ten long wall units, then I could cast walls to my heart’s content.

Or if I’m going to make walls that way, should I just go ahead and buy the “right” Hirst mold? Since I’m not reselling anything I don’t believe there’s any problem with making molds of blocks for my own use, but still I feel like making a mold like that isn’t really very nice to the folks at Hirst who make very nice molds. Plus I’ve got my own wall mold I’ve been using to cast my own wall elements (I have fourteen four-inch walls now). So I don’t really need the Hirst walls and I actually prefer the ones I am making since they are much thinner and don’t take up a full square to lay out a wall.

So I suppose I won’t make a mold for wall elements….

But what about floor elements?


I’ve been playing with another idea to have a steel rule die made so I can cut shapes out for my own use, but I don’t know how much a steel rule die costs….

The tower mold doesn’t have any obviously re-usable blocks, they are almost all shaped in an arc for building the walls of the tower, or fitting into the walls of the tower, so there’s no benefit I can see in making a mold from any of those elements…

It’s pretty cool, I’ve got a huge pile of blocks drying on my floor…

Hirst molds (52 & 74)

Here are two molds my wife got me for Christmas. Totally unused so far:

The one on the left makes this:

The one on the right makes this:

Of course you can make other things with them too, but these are what they are designed to make.

Each one takes about 20 complete castings of each mold to build the bridge or tower… Yeah. 20. Each casting takes at least half an hour, probably closer to 45 minutes, so the casting of the mold elements alone will take thirty hours to make both items. So don’t expect to see one or the other pictured here for a bit….

Fort Pringles 2

Here is the current state of Fort Pringles, the fort I am making out of a pringles can, a couple of nut cans and some foam core poster board… No real reason it’s taking this long to complete, just working on it from time to time…. Anyway, here it is.

The corner towers will also get crenelations, I just haven’t gotten to it yet. Plus I still need to cut out the main and secondary gates, and put in the drawbridge.

The inner building will end up being at least three stories, with a crenelated roof of its own.

My current plan is for the floors to contain store rooms, barracks/bunks, cells, kitchen/dining area, armory, military library and whatever else I can think of.

More bookshelves

These are empty shelves so far. I just whipped them up using my wood nippers and popsicle sticks, with some small sticks used as shelf braces. Once the glue dried on them I dipped them in pecan Minwax. Nothing to it, I made about a dozen bookshelves in probably 45 minutes while listening to a football game on the radio…

More stone walls

Here’s a couple stone walls using the same imprinted pattern for stones. The one on the left is a smaller wall, and more organic, suitable for a garden or to separate houses. The one on the right is intended to be a section of a building’s wall.

The one on the left is just plaster (actually dental plaster) cast from a clay mold I just whipped up. The one on the right has more effort behind it. First I made a two part mold out of sculpey clay, then baked the sculpey so I have a firm mold. I’ve made two casts from it so far and they came out really nice. The sculpey mold shows no signs yet of degrading. I used mold release on one cast but not the other and they seemed to work about the same well. I will be casting lots of these wall sections now, and will be using them to make larger buildings or even castle walls.