rotary hammer vs small demo breaker

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  1. #1
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    Default rotary hammer vs small demo breaker

    G'day All

    I want/need to break away the front corner of a wall footing which (mostly) wasn't adequately boxed when poured.
    the bit I need to get rid of is about 200mm deep & up to 150mm wide. (marked in red on the drawing attached)
    There's about 35M of wall this needs to be done.


    I had a bit of a go at it with a hired Hitachi H65 Demolition Hammer some time back, which was not successful.
    My thinking now is to drill 200mm deep holes every 100mm or so, & break out the chunks in between.
    (350+ holes... )

    What is going to be the best tool (or combination) for the job?

    For example, would an SDS-plus tool be up to the breaking bit? eg Ozito RH1500 or Hitachi DH30PC2
    If so, at $110 vs $650, is there enough difference in the working speed & pleasure of use to warrant
    going the Hitachi (or Makita/Metabo/Hilti equivalents)

    Or would I perhaps be better served by doing the holes with an Ozito RH1500, & get the Ozito DBR-1500
    with the SDS-max chuck to do the breaking? (total cost close to $400)

    Would the higher quality rotary hammers be as good/quick as the Ozito combination?
    (leaving a better quality tool as residue.)

    My preference is for better quality tools - I've had enough of cheapies, but 6x the price is enough to make one blink a bit...
    cheers
    Alan J
    Attached Thumbnails Attached Thumbnails wall-cross-section.jpg  

  2. #2
    3K Club Member johnc's Avatar
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    After drilling holes all along the full distance, if you can make up something like these stone splitting wedges you may get lucky and be able to split to a face. You need a few sets and gradually tap in sequence until you start to get a split between the holes then keep even pressure until it fully splits. Have you thought about a 9" grinder with a diamond wheel?



    Wedge & Shims
    Also known as Wedge and Feathers. These tools are the oldest and still one of the best ways to split stone. Small wedge and shims in 5/8" and 3/4" sizes are good for stone yards or stone masons who want to reduce their rocks to workable sizes. Larger sizes 1", 1-1/4", 1-3/8" are for splitting large rocks. Our high quality wedge and feathers are made for splitting granite and other hard stone.

  3. #3
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    Thanks for the response John
    The big grinder with (dry) diamond wheel was an early discard due to dust.
    The footing actually extends into my neighbour's property & I want to bring it back to the boundary, at least on the surface.
    I'll be working on my neighbour's side of our boundary, so I want to minimise mess.
    here's an extended drawing

    wall-cross-section2.jpg

    The drill still produces dust, but it stays close to hand for easier clean-up

    I have considered hiring a 400mm wet disc concrete saw for a day.
    Would leave a much cleaner finish along the top edge of the workings, which is the facing edge of my neighbour's garden bed,
    but the slurry run-off into the garden probably won't do the plants any favours.
    Also, I think I can drill closer to the wall than I can cut.
    cheers

  4. #4
    1K Club Member Godzilla73's Avatar
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    G'day,

    Is there enough room to get a demo wet saw in there, 35m of what you're considering would be painful. Get a price to hire one for half a day, then break it with a decent jack hammer like this which you could also hire.

    001-resized640x480.jpg

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    Thanks Godzilla
    The mix of jack hammer & saw is certainly an option.
    There are only a few spots where I wouldn't be able to get the big saw into.

    I had a hired hammer rather like your picture - a 16kg Hitachi H65
    Made sod-all progress in a couple of hours for an excess of effort.
    I couldn't handle a whole day on a big jack hammer.

    How to manage the slurry run-off from the saw?
    cheers
    AJ

  6. #6
    1K Club Member Godzilla73's Avatar
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    I found the slurry less off a hassle as it was all contained on my property and i was doing major reno's so already heaps of mess about. I reckon you'd get more complaints about dust without the water.

    Do you know the Mpa of the concrete? The Makita version i used just ate it up no probs...

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    When you look at the Ozito tools there is usually a little tag to say it is not for trade work or words to that effect. Considering the amount of work you plan (350+ holes) a better brand could serve you well, or hire a trade tool like a Hilti, just be prepared to buy a couple of bits.
    If wet sawing make up some sort of dam wall to contain the slurry.

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    Sorry. Don't know the MPA. Harder than any path I've broken up in the past.
    The Big Hammer just chipped little bits off it, unless I could get it behind a dag, or into a crack.
    Thinking that multiple deep holes, close together might 'soften' the structure between them a bit.
    Poking around at it today, spotted a 3M section where I need to go down closer to 300mm than 200mm..

    Enjoyed using a 450mm quick-cut on some pathways.
    80-100mm deep, 500mm squares for the bobcat to take away.
    However, working it along a rough edge, to maximum cut depth, and without a stable rest...
    I drive an office chair for a living - apart from riding a treadly to work, I'm pretty soft.
    Saw: $180/day... Jackhammer: $80/day... adds up quick if I bend the disc, or the job spills past one day on each tool due to my softness.

    However, I'm about to have plenty of spare time as my job goes off to India.
    A few hours a day for a week or so is no issue...
    Hence the leaning towards tools that I can own for a fixed price rather than hire.
    Especially ones I'm likely to have further use for when this job is done.
    Drill bits are relatively cheap...
    Does this make sense?
    cheers

  9. #9
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    thanks Handyjack.
    anyone know the effectiveness of the 1500W Ozitos compared with 30 - 32mm class brand-name tools?

  10. #10
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    Quote Originally Posted by b.o.a.t. View Post
    Thanks for the response John
    The big grinder with (dry) diamond wheel was an early discard due to dust.
    The footing actually extends into my neighbour's property & I want to bring it back to the boundary, at least on the surface.
    I'll be working on my neighbour's side of our boundary, so I want to minimise mess.
    here's an extended drawing



    The drill still produces dust, but it stays close to hand for easier clean-up

    I have considered hiring a 400mm wet disc concrete saw for a day.
    Would leave a much cleaner finish along the top edge of the workings, which is the facing edge of my neighbour's garden bed,
    but the slurry run-off into the garden probably won't do the plants any favours.
    Also, I think I can drill closer to the wall than I can cut.
    cheers
    We used to cut with two, one with the grinder the other with a hose running a slow trickle into the cut at the point the blade enters. We didn't attempt any Darwin award entries, water slurry was minimal, dust zero and never worked standing in puddles or with damp cords or grinder. Occ health and safety probably wouldn't allow it these days I guess.

  11. #11
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    Done that with my 125mm grinder.
    Wearing rubber electrical gloves & behind an RCD...
    I guess different grinders behave differently - took a lot of water to stop it flinging dust.
    Then it flung mud... which stings on your bare leg let me tell you !!

    Nipped around last night with a chainsaw to simulate the big quick-cut.
    Could probably do 2/3 of it like that, but access very poor for the other 1/3.
    Plants, garden edging, etc...

    Leaning towards trying an Ozito for the holes. Other threads suggest quality is mixed.
    Tend to either be very good & last the distance, or fail on day 1 or 2.
    Heck they're only $110 with a generous returns policy.
    If it really isn't up to it, then I'll spring for something better.
    Probably go with 10-12mm holes for speed & ease of drilling.
    And hire a big hammer for the breaking.
    3 days hire is same cost as buying the small Ozito.
    I think I can manage that work-load.

    So thank you all for your input.

    Any secrets to maximising life of a masonry bit?
    cheers

  12. #12
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    Quote Originally Posted by b.o.a.t. View Post
    ...
    Any secrets to maximising life of a masonry bit?
    cheers
    As always, let the tool do the work but this is especially important with a rotary hammer drill, as too much pressure will restrict the tool's ability to punch with maximum efficiency and may overheat the bit

  13. #13
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    Sounds like a lot of cost and effort to appease the neighbor - hope she's really good looking
    David L
    "A dedicated amateur will always do a better job than a slap dash professional"

  14. #14
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    That's a lotta concrete to remove for sure!
    When you were using the demo hammer, what kind of chisel did you have? A point chisel is the tool of choice for major concrete removal, and picking one up in the long size will save your back. Then tidying up with a flat if needed.

    You'd pretty much have to work from the side and work your way across too. I'd probably cut some lines with a concrete blade vertically to help it along first.

    Don't envy you one bit

    I'd probably just hire something solid around 7-10kg worth of drill, because you can buy the Ozito but it won't have the gumption to get that job done in any decent sort of time frame.

  15. #15
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    Bought the Ozito thinking that if it's a total dud then it's only $110 down the gurgler.
    So far in 3 days have drilled all my fence holes (150mm x 16mm in about 20 secs each),
    removed & reinstalled 14 of 15 panels, and chipped off about 300-500kg of excess footing.
    FAR more than I achieved in a day with the full sized demo breaker.
    The smaller tool can be presented to the job more accurately than the big one, and taking
    smaller bites makes it disappear faster.

    We've also agreed that with the fence on its proper alignment & with some back-fill
    along its base, the footing is far less... "intrusive" than it earlier appeared, and the
    rotary hammer has been tool enough to handle the reduced material removal.
    Am I happy?.... You betcha !!
    Thanks All
    AJ

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