Lunar SPORE Project Update 51

SPORE Project Update

Hi there. Just wanted to let you know I’m still working on the Lunar SPORE project.

Work on the project today:

  • I’ve been thinking about my next step to get the basalt gravel crushed into the particle sizes I want for the SPORE Pressure Experiment 1.
  • I was about to give up on the manual methods, bite the bullet, and just buy a powered machine to do the dirty work. Then I ran across a guy that crushes quartz (for gold prospecting) using a fence post driver and a piece of pipe. Interesting, tell me more…. That led me to a couple of other manual options. Here are the choices I have so far:
    • Modified iron skillet and hammer
      • OK, so the idea is to attach a 50 cm length of PVC pipe to the skillet. The diameter would be 2.25″ (slightly larger than the diameter of the hammer). I would cut a section out of the pipe that would allow the hammer to move up and down. That should contain most of the rock shrapnel. Cost = maybe $10.
    • Fence post driver stamp mill
      • Fence post drivers are used to drive fence posts into the ground. In this case, I would turn it upside down so the opening is facing up. I would put a handful of gravel in. And then I would use either a metal pipe (with a cap) or a solid metal rod to crush the rock. Very little rock would fly out. The driver is 3″ in diameter so not much different than the modified skillet approach. Cost = maybe $80.
    • Black iron pipe
      • Black iron pipe is used to transport natural and propane gas in residential applications. It’s actually made from mild steel but it’s pretty durable and heavy. The idea is the same as the post driver, a larger pipe with a smaller one inside. The problem is that 3″ diameter black iron pipe is pricey. A 10′ length (which is much longer that I would need) goes for $282. Even a 2″x48″ length is $53. So with 2 pipes plus caps I’m looking at a minimum of $140, if I can even find the sizes I want.
    • I found a something similar to the post driver for sale (
      • My concerns are twofold. One, it’s only 9″ tall. I’m not sure that’s enough travel to get the energy needed to crush the rocks. Two, I can’t find ANYTHING on it on the Internet. No reviews. No videos. Nothing. I find that a bit strange. It costs $82 plus shipping.
    • Then there is the CrazyCrusher (
      • This thing looks like a beast. And if I had the space to store it (and use it) and the money ($500) I would definitely get it. Not at this time though.
  • Electric ball mill (aka rock polisher)
    • These work by placing your rocks and some steel balls into a horizontal container. And then rotating that container fast enough that the balls come up along the side of the container and then drop back down into the rocks below. Do this enough and you get a fine powder. I don’t think ball mills will be very effective on Luna because the 1/6g gravity will really reduce the amount of kinetic energy the falling balls put onto the rocks. But it seems pretty good for my purposes. They’re not too expensive either. I can get a cheap one for about $60 and a better one for $160.
  • Angle grinder impact mill
    • This is mostly a DIY project. I would have to buy an angle grinder and then the mill for it. The designs I’ve seen used welded chain links inside a steel box to break up rocks. I don’t have the tools or the space to build this right now. But impact mills will probably be the way to go for Lunar rock grinding. They aren’t dependent on gravity to do the job (like stamp and ball mills). I only found one pre-made unit for sale and it was about $500. Too pricey for my blood.
  • Jaw crusher
    • A jaw crusher is a V-shaped machine that pushes one side of the V into the other, crushing the rocks between. The V is made from steel and the whole thing is usually driven by an engine. There are some DIY manual designs out there but I don’t have the facilities to build them. Jaw crushers are really effective at breaking large rocks into little ones so I’m definitely going to figure out how to make a Lunar Homestead version. Just not for this project. Plus, they aren’t cheap to buy. I’ve seen them run from $400 to several thousand.

As you can see, I have a few choices. I need to decide if I’m going to put more time and money into the hammer route, try the post driver option, or invest in a ball mill. The other options are either too expensive or too large. I’m going to think about it tonight and have a plan by tomorrow.

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