I need to move some big rocks out of the way so I can dig down and put a drain pipe along the base of a wall that leaks into my shop in the basement. So not having a backhoe, I'm going with the old standby of breaking them into pieces I can lift. I bet at least a couple of you guys know how this is done, but since I had a camera handy I went ahead and took some pics

First drill some holes. These are 5/8" because that is the size bit I have for the little drill (40 year old Milwaukee hammer drill). I have more wedges for 3/4" but that is a real struggle in the Milwaukee and the Bosch demo hammer is waiting on O-rings to get it hammering again.

Next is to set up the wedges and feathers and get them seated in the holes. Once they are tight I just give each a tap or two and move on to the next one so as to get a crack started.

You can just see the crack starting

Bigger, but not fully loose yet. You can here the change in sound as the crack completes, tapping on a wedge goes from a sharp ping to a dull one with a hollow ring echoing out of the crack.

Now the crack is complete, the point chisel is getting hammered in so I can pull the wedges out.

There's the crack going all the way down to the soil below. First cut I did on this one the top half separated from the bottom where the rock changed (sandstone to a more mixed conglomerate - the larger clasts in the conglomerate can impede the cracking - just like you want in concrete with a range of aggregate sizes).

That piece was too heavy to lift still - which didn't stop me trying!

So I split it again and managed to lift these two out of the way.

The cut face of the rock (one of those halves). You can see the bigger gravel clasts in the rock I was talking about.

The trench is now open enough to dig down and put in a drain.

One more rock to do. I may wait until I fix the Bosch! Drilling the holes is pretty slow going!

I hope it was an entertaining set of pics for everyone. Kinda fun to do it, other than the drilling.

Cool!

In my younger days, and with the help of the World Book Encyclopedia, we would have mixed up some gunpowder.

1 minute ago, lew said:

Cool!

In my younger days, and with the help of the World Book Encyclopedia, we would have mixed up some gunpowder.

Heheheh.... yeah, that was my dad's speed too!

3 minutes ago, JWD said:

Heheheh.... yeah, that was my dad's speed too!

Hahahaha!

I have one to split this year, I'll be moving it with a compact tractor, but at the moment it's too big for even it to lift. I bought some demo grout and the proces is sort of the saem. You drill a series of holes, larger ones 1.5", and pour the grout in. It expands cracking the rock. I'll be renting an SDS to do the holes. But mine is in the middele of the yard, which should makes things easier.

Edited March 9Mar 9 by Fred W. Hargis Jr

2 hours ago, Fred W. Hargis Jr said:

I have one to split this year, I'll be moving it with a compact tractor, but at the moment it's too big for even it to lift. I bought some demo grout and the proces is sort of the saem. You drill a series of holes, larger ones 1.5", and pour the grout in. It expands cracking the rock. I'll be renting an SDS to do the holes. But mine is in the middele of the yard, which should makes things easier.

That's more like the really old way of doing this - big holes with wood plugs soaked in water on a freezing night!

I've drilled holes that big once, the large bit tended to want to grab in the hole and spin the drill instead of the bit. It was rough going! I've never heard of demo grout, I wonder what it's composition is? Gypsum maybe? I wonder how they keep it from just expanding out the top of the hole? Interesting product from the sound of it.

This is the stuff i bought. I'd never heard of it until Roly (past member) mentioned it on another forum.

.

Wow! Never heard of it either. Is it worth $50?

I would bet it's gypsum for the most part, I think it's the mineral that expands the most when mixing with water.

Very interesting idea, their website has lots of photos - from those it looks like a method that works especially well for something you might otherwise blast. The problem often seen with blasting is that overloading is pretty common for practical reasons, so you get a lot of flying chunks. Hard to estimate what the rock is going to do when blasting, and I think they really only get one shot at it. This stuff looks more slow and steady.

My only concern when using it in place of small wedges is that I think you probably need pretty deep holes unless the rock is unsupported on the sides. May not be an issue for what you are doing, as it wouldn't be for what I'm doing.

Looks like it's a recent enough product that there's no info on wikipedia or the usual places - just marketing info and AI descriptions that don't tell you the mechanism of action. Still, a cool idea is a cool idea 😀

1 hour ago, MrRick said:

Wow! Never heard of it either. Is it worth $50?

It is to me. This rock probably weights close to 3500# (my tractor can lift about 2000#) and an excavator wanted $400 to move it for me. SDS rental might be $70, so all told I'm still saving money. Of course, that assumes it works.

Edited March 9Mar 9 by Fred W. Hargis Jr

37 minutes ago, JWD said:

My only concern when using it in place of small wedges is that I think you probably need pretty deep holes unless the rock is unsupported on the sides. May not be an issue for what you are doing, as it wouldn't be for what I'm doing.

They say 12" deep. I'm not sure I have to go that deep, but we'll see. I checked the label to see if it had any composition info, it didn't.

Edited March 9Mar 9 by Fred W. Hargis Jr

25 minutes ago, Fred W. Hargis Jr said:

They say 12" deep. I'm not sure I have to go that deep, but we'll see. I checked the label to see if it had any composition info, it didn't.

Yeah, any more they don't tell you what is in anything if they can avoid it.

I would guess you need at least 30% of the rock thickness for an unsupported rock. If the grout is basically gypsum, the good news is that it will drill back out easily if it doesn't go the first time.

thank you for this post; after spending 45+ years in the mining industry i finally know what the wedges that were used to split building stone actually look like, for years i have had the idea that they were tapered but now i know, thanks again😄

37 minutes ago, Rusty S said:

thank you for this post; after spending 45+ years in the mining industry i finally know what the wedges that were used to split building stone actually look like, for years i have had the idea that they were tapered but now i know, thanks again😄

These are very small versions 😀

Sized for a quarry they would probably be 2" holes or something like that.

My dad worked in a granite quarry in New Hampshire before I was born, I think he worked in the slabbing shop rather than the quarry itself, he always referred to a machine called "the burner" that I think was like a big version of an electrical discharge machining set up. I've also seen pictures of a big bandsaw kind of machine with carbide or diamond teeth set in wire rope. That was at a quarry in Nevada that was quarrying something soft like a pumice if I remember correctly. Too flexible for really hard rocks.

Glad you enjoyed it!