"Boulder blaster" commercial or self made.

[Assembler]

There is still the receiver / action sticking out of the ground.
Why not have the entire cannon sticking out of the ground and just fill the hole with water.
There is no problem with 12 gauge shells as they have been used for at least 200 years or so.

With say 21" of barrel containing the energy before going into the hole in the rock there will be more powder burned thus more energy to break the rock open. I will be using a 24" barrel with about 21" of barrel after the shell / load. This will be better then a 1 1/2" hole in the rock.

 

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[Assembler]

With say 21" of barrel containing the energy before going into the hole in the rock there will be more powder burned thus more energy to break the rock open. I will be using a 24" barrel with about 21" of barrel after the shell / load. This will be better then a 1 1/2" hole in the rock.

There is a fair amount of gases / energy lost whenever the hole in the rock starts to open up. There will be more energy applied to the water column if most of the powder is burned up first. The pressures will make this happen. The Law's of physics tells us this.

 

[Assembler]

There is a fair amount of gases / energy lost whenever the hole in the rock starts to open up. There will be more energy applied to the water column if most of the powder is burned up first. The pressures will make this happen. The Law's of physics tells us this.

Anyone use a hole cutter for making deep wads for a 12 gauge barrel?

 

[Assembler]

Found a cheep Mosberg barrel to make the project out of.

Will cut and grind off the sights first. Will have to brush up on my machining skills............lol.

 

[BlasterJ]

Found a cheep Mosberg barrel to make the project out of.

Will cut and grind off the sights first. Will have to brush up on my machining skills............lol.

What you're describing sounds a lot like a "water disruptor" that bomb squads use. It might work on rocks. Lots of info if you Google that term.

 

[Assembler]

What you're describing sounds a lot like a "water disruptor" that bomb squads use. It might work on rocks. Lots of info if you Google that term.

Wow thank you for the tip there BlasterJ.
Will take a look at this as this is a long project in the works.

 

[Assembler]

Water will not compress very much however the rock will is the idea here. The cannon will have to take a fair amount of pressure unlike a thin shotgun barrel. You do not want to be standing next to this if there is any chance of a breach or the rock flying back at you.

 

[Assembler]

For tomorrows weather:

 

[Assembler]

Looks like I have found a frame with movable attachment that will work for a small boring bar. This will have to be mounted on the end of the lathe in order to work for light cuts.

 

[eyemustdigtreasure]

"Boulder Buster", uses standard 12 gauge cartridges.
Anyone use one or know of someone who uses one?

I did come across someone over seas who made one. Just checking here if anyone uses one.
Thank you.

Well, no, but I know some that use 22 shells as a micro-blaster...!

 

[Assembler]

Well, no, but I know some that use 22 shells as a micro-blaster...!

Almost any size case can be used however one needs to know what kind of pressures are involved so as to not hurt yourself and others around.

 

[Assembler]

The fellow over seas machined his own small cannon. The rocks he is breaking up are amazing as I saw a photograph.

 

[BlasterJ]

According to the data sheet for the blasting cartridges I use (not boulder buster, this is NXburst and goes completely down-hole), the maximum pressure generated is around 140,000psi.

 

[Assembler]

According to the data sheet for the blasting cartridges I use (not boulder buster, this is NXburst and goes completely down-hole), the maximum pressure generated is around 140,000psi.

Now you are talking as this shows why it works. Is this designed for 1" holes?

Yep you do not want to be holding on to this when it fires off.

 

[BlasterJ]

Now you are talking as this shows why it works. Is this designed for 1" holes?

Yep you do not want to be holding on to this when it fires off.

They have a product for 5/8" holes, 1 1/4" or larger and then several size after that. Full details are in the manual:

https://www.nxburst.co.nz/Nxburst%20Training%20Manual%20July%202014.pdf

 

[Assembler]

They have a product for 5/8" holes, 1 1/4" or larger and then several size after that. Full details are in the manual:

https://www.nxburst.co.nz/Nxburst%20Training%20Manual%20July%202014.pdf

Wow thank you for the link to the manual BlasterJ. I did not get to it until today as I was doing the Cyber Monday thing.........lol.

I read in the manual the following:
Nxburst

40 grams per ton, with the 5 – 10 gram charges hole spacing of around 8”, holes should be 70 percent through the rock.

 

[BlasterJ]

Wow thank you for the link to the manual BlasterJ. I did not get to it until today as I was doing the Cyber Monday thing.........lol.

I read in the manual the following:
Nxburst

40 grams per ton, with the 5 – 10 gram charges hole spacing of around 8”, holes should be 70 percent through the rock.

Those rules are somewhat flexible. They discontinued the 5g cartridge, but I can say that the 10g will break up to maybe a cubic yard rock using an 18" long x 5/8" drill hole, assuming the rock is pretty round or square and not surrounded by dirt. Breaking "in situ" rock with these products requires sawing, digging or otherwise exposing a free face for the rock to break into and you need to use more and/or bigger charges. I took apart that 15 yard / 70,000lb boulder with around 10 cartridges, mostly 40g and 1-2 60g. This was right next to a house and they only needed pieces that heavy equipment could move, not pre-fragmented rock.

 

[Assembler]

Those rules are somewhat flexible. They discontinued the 5g cartridge, but I can say that the 10g will break up to maybe a cubic yard rock using an 18" long x 5/8" drill hole, assuming the rock is pretty round or square and not surrounded by dirt. Breaking "in situ" rock with these products requires sawing, digging or otherwise exposing a free face for the rock to break into and you need to use more and/or bigger charges. I took apart that 15 yard / 70,000lb boulder with around 10 cartridges, mostly 40g and 1-2 60g. This was right next to a house and they only needed pieces that heavy equipment could move, not pre-fragmented rock.

10 grams is around 155 grains of powder charge. Two 155 grains shells should have no problem as a general rule spaced out in a line.

Don't know the time it takes to drill say a 3/4" hole compared to a large 1 3/4" - 2" hole yet. Maybe both sizes holes can be used.

 

[BlasterJ]

A 1.5" hole is 4X the area of a 3/4" hole and a 2" hole is about 7X the area of a 3/4" hole. That's a good starting point for driling time/battery packs required.

 

[Assembler]

A 1.5" hole is 4X the area of a 3/4" hole and a 2" hole is about 7X the area of a 3/4" hole. That's a good starting point for driling time/battery packs required.

That sound correct. Looks like I will be shopping for a number of different drills. Looks like a 2" hole can take up a part of the day drilling depending on the rock and how deep.