Break big rock without shattering it

sen5241b

Reef enthusiast
I have a brain coral on a big rock shaped like an army helmet and there is no way my single MH bulb can shine on all sides. I rotate it on a regular basis but it is not enough. I need to crack the rock in pieces and then place the pices so all polyps get light. Anyone broke a rock? Is there some method to prevent it from shattering?
 
I broke a rock a few months ago with a chisel and hammer because it was so big and I didn't like the way it fit in my tank. The rock broke pretty much the way I wanted it to but I didn't have anything on it. I just angled the chisel where I wanted the break to be and hit it with the hammer. Ended up with some rubble as well but not much.
 
How a rock breaks is really dependent on where the natural fissures are in the rock. Even if you have a specific place you want the break to be and hit it exactly where you mean to, there is always a possibility that there is a fissure running in a different line and its going to break where that fissure is. That is just the nature of rock.
 
I've done it before, I drilled small "fault line" holes in it with a masonry bit first. and then whacked it with a hammer and chisel. Worked no problem.

1. Don't press hard on the drill.
2. Don't hit too hard with the hammer.

That rock is much softer than it looks.
 
Best bet here would be to get a drill and a bit designed for drilling rock or stone and to drill holes along a line of where you would like it to crack. Once you've done that use a hammer and chisel near the center of the rock and it should break roughly along the line you would like it to. The bigger the rock the more holes I would drill though.

rdahlke1105 is correct in that the rock will break along it's natural weak points but if you create artificial weak points that are weaker than the natural ones it will break there.

*Edit* Damn beaten to the punch.
 
Never knew that the geology class I took in college would ever benefit me. :) Now I know that it was a good thing to take. :lol:
 
I've done it before, I drilled small "fault line" holes in it with a masonry bit first. and then whacked it with a hammer and chisel. Worked no problem.

1. Don't press hard on the drill.
2. Don't hit too hard with the hammer.

That rock is much softer than it looks.

Oldest trick in the book for making a hole in a cinder block wall.:mrgreen:
 
Masonry bits are designed to go through rock. It will work fine. If you have one available, I would think you could also use a tile saw. I believe that is what is usually used to frag favia since most of the time, I see them on little square frags.
 
Masonry bits are designed to go through rock. It will work fine. If you have one available, I would think you could also use a tile saw. I believe that is what is usually used to frag favia since most of the time, I see them on little square frags.

Was just going to sugget the same thing. If you know anyone with a coral band saw, cut that sucka in half :mrgreen:
 
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