Boring through concrete (cement)

[Anonymous]

I would like to bore a 250 mm or 10 " hole through a concrete block wall about 200 mm thick. How would you go about it.


Rgds ian

[Curmudgeon]

Series of small holes.
There are commercial core borers that do about a 2-1/2" hole, but a masonry bit and a hammer power drill, do a series of holes all the way around, like perforations in paper, and hit it with a sledge is the way we had to do it.

[Capt Bob Johnson]

Got an old army buddy? Shaped charge with plastic explosive??? If done right, and with proper expertise, would be quicker, less work, easier to clean up after!

[Curmudgeon]

Bets it's the foundation to his house and guess what the explosives will do.....

[Anonymous]

Actually I have to do the same thing in my back yard, a tunnel into a 6" thick block wall. The cores of the cinder block have been filled with concrete.

I'm going to bore a series of 1/2" diameter holes in the shape of the tunnel portal, somewhat inside the line I want. This is easy to do with a hammer drill and a carbide tipped masonary bit. It's easy to get this size drill long enough to go through.

Then, you can use a small chisel to knock out the concrete between the holes. Wou will need to drill a number of holes, but you have much less risk of cracking the part of the concrete you want to stay.

After that, a 3 or 4 inch diamond blade in a cutoff tool (I use air powered tools) to smooth the inside of the tunnel.

I have asked a number of people that work with concrete, as well as my 2 landscapers who built the walls, this is the consensus.

Regards, Greg

[markperr]

Okay, here comes the obligatory warning. When you start cutting the concrete make sure you have eye, ear, and lung protection.

Mark

[vsmith]

QUOTE: Originally posted by Curmudgeon

Bets it's the foundation to his house and guess what the explosives will do.....

Create a new Rec room..??? Or is the Wreck room...[:0][:D]

[Capt Bob Johnson]

Greg,
Just hope they didn't shove rebar down there when they filled the cores!

[Anonymous]

Yes Greg i agree with you, I have thought to do it that way, I am thinking of constructing a 35 m 115' elevated track through area 2 conecting my viaduct in area 3 direct into the reversing loop in area 1. This will really make my layout much more versatile. I want it to look nice so I am thinking of using aluminium "U" channel to support track and ballasting. It will run right under a water feature near my pool.

I have an ornamental wall wherer area 2 and 1 join and i can either go around it or through it ( not under or over it)

Has any one ever entered a track into the middle of a reversing loop (MTS) if so were their any unforeseen disasters?


Rgds Ian

[tangerine-jack]

Concrete block wall?
Assumption #1: the blocks are about 8X12
Assumption #2: the hole will contact 1 or more blocks
Assumption #3: the section is not load bearing
Solution #1: sledge out all the blocks cleanly, insert tunnel, rebuild section of wall with smaller brick or rubble mix.
That's what I would do simply because I like breaking things with a big hammer and don't have the time to mess around with drilling 30 freakin' holes in a masonary wall.

Solution #2: do what Capt Bob said[:-,]

Good luck!

[oX)]

[RhB_HJ]

QUOTE: Originally posted by tangerine-jack

Solution #2: do what Capt Bob said[:-,]

Good luck!

[oX)]

Addendum to solution #2: be sure to take Slow-Mo pictures to be posted here. Best as "before-after" sequence.[8)][;)]

[Anonymous]

I do expect to find rebar, there is rebar in every core. By drilling, I should be able to knock out the pieces between, and then a carbide cutoff wheel on an air grinder will make short work of the rebar. It will take longer than the sledgehammer method but I should make minimum damage to the wall. The wall is capped with expensive masonry work, so I have to tunnel.

Greg

[bman36]

QUOTE: Originally posted by gregeusa

I do expect to find rebar, there is rebar in every core. By drilling, I should be able to knock out the pieces between, and then a carbide cutoff wheel on an air grinder will make short work of the rebar. It will take longer than the sledgehammer method but I should make minimum damage to the wall. The wall is capped with expensive masonary work, so I have to tunnel.

Greg

Hey there,
The nicest tool I have seen yet is a commercially available boring or "coring" drill. Portable...very compact and can be set up just about anywhere. Will drill clean holes through just about anything. We used one for anchor pots on a concrete floor. For several holes it is the only way to go. Drill bits take longer but will definately do the trick for just one. Later eh...Brian.

[Anonymous]

Yeah the core drills are sweet. Unfortunately, the track enters the wall at an angle, so not only would I need to drill at an angle, the hole is about 12" in diameter, and then would have cut down to come up with an inverted "U" shape. The space in front of the wall is too tight to fit the machinery, darn.

Would be much nicer to see someone else break a sweat!

Thanks, Greg

[tangerine-jack]

Good idea, in situations like this, it's always best to just pay some poor slob to do the job for you. Sit back with a cool one and enjoy the show, I say.


[oX)]