undercutting stone/ brick fireplaces

Discussion in 'The Bucket' started by Don Monfils, Jul 13, 2019.

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  1. Jul 13, 2019 #1

    Don Monfils

    Don Monfils

    Don Monfils

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    So I just picked up a diamond blade for my Crain 812 undercut saw. Any pointers or advise on undercutting stone or brick.
    I have always scribed to fireplaces.
     
  2. Jul 13, 2019 #2

    highup

    highup

    highup

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    Dust collection in every way you can come up with. I'm sure a second person with a good vacuum hose held almost on the blade would be a good idea. I modified my 4" angle grinder to do under cutting, but I've only done it a few times. I just used a reconfigured cardboard box with a hole in it to connect my vac hose. I kept the box right up against the grinder as I went along. Large grit and fine dust was directed to the boxes opening, so most went in there and got sucked up.
     
  3. Jul 13, 2019 #3

    Don Monfils

    Don Monfils

    Don Monfils

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    0A7A2497-1AC2-4530-B9B1-40D7A26FD777.jpeg My saw has a dust port for a tiny vac hose.
    I’m thinking of using that and also have someone follow with a big shop vac close to the blade ( like you suggested)
     
  4. Jul 14, 2019 #4

    highup

    highup

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    I have a photo of my shoddy little box saved somewhere but can't find it. I trimmed a box down to maybe 3 inches tall by 10 by 15 or so with the top and one end open. Looks more like a dust pan. Anyway, you cut an opening for a vac hose on the end and put a little weight on it... nothing heavy, just a scrap of plywood. I think I added a narrow carpet scrap along the hearth side of the box as a gasket of sorts.
    I work solo so I have to do crazy stuff like this sometimes. You might do as well with the second hose as you mentioned and maybe use a narrow or a crevice tool on the vac wand and held right close to the blade.
     
  5. Jul 29, 2019 #5

    Ernesto

    Ernesto

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    Grab an adapter at HD to go from the small port to the shop vac hose. Comes in three pieces, the bigger tubular one is just for connecting multiple hoses. Its the two smaller ones you use.

    https://www.homedepot.com/p/RIDGID-...Kit-for-Wet-Dry-Vacs-3-Piece-VT1755/202077239

    Or this hose I usually get with my dustless technologies grinder shroud.
    https://www.amazon.com/Dustless-Tec...+technologies&qid=1564437005&s=gateway&sr=8-8

    I use the Crain 835 cus it can get under tight spaces where the 812 can't.
    https://www.craintools.com/saws/power-undercut-saws/835

    Also advice, I do two cuts, a flush cut at the bottom of the substrate, then the cut the height of the flooring going in. Then you may have to use a demo hammer to chip off any residual chunks still stuck.
     
    Last edited: Jul 29, 2019
  6. Jul 30, 2019 #6

    Don Monfils

    Don Monfils

    Don Monfils

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    Thanks, that’s some good info !
    Good thing I wasn’t hanging from a cliff by my fingertips waiting for an answer:D
     
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  7. Jul 30, 2019 #7

    Ernesto

    Ernesto

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    Don, not sure why I didn't see this thread earlier. It just didnt pop up.
    I have a barely used 810 because it wasn't set up with a dust port. Also a really old small Robert's undercut saw if any of you guys want them . You pay shipping.
    PM me.
     
  8. Jul 30, 2019 #8

    Don Monfils

    Don Monfils

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    I will take the 810
    I have a brand new blade.
    I had 2 older 810’s that burned up in my garage fire.
     
  9. Jul 30, 2019 #9

    Don Monfils

    Don Monfils

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    I just read the pm thing.
    I can’t find where I can send a pm.
     
  10. Jul 30, 2019 #10

    Ernesto

    Ernesto

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    You should just be able to click on my name, then on start a conversation. Send address.
     
  11. Jul 30, 2019 #11

    highup

    highup

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    Do you use a Dust Deputy or just an empty vac that sucks the dust and blows it into the neighborhood.?:D
    yah, that's what I thought. :eek:
     
    Last edited: Jul 30, 2019
  12. Jul 30, 2019 #12

    Ernesto

    Ernesto

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    I use these. A hundred times better than those cheapo paper ones. I have a cousin who has a lady sew in a zipper so he can use them over:
    • Fits most models of wet dry vacuums
    • Filters 99.97% of particles at 0.5 microns
    • Capable of holding 40 lbs of debris
    • Retains its strength and filtration while vacuuming water
    • Comes in a 2-Pack
    https://www.amazon.com/Wunderbag-Un...technologies&qid=1564497012&s=gateway&sr=8-11

    Plus I use it in this vac that has two washable cloth filters in it.
    https://www.amazon.com/Dustless-Tec...ocphy=9030261&hvtargid=pla-637512083189&psc=1
     
  13. Jul 30, 2019 #13

    highup

    highup

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    I figured bags would clog up pretty fast, especially if you are grinding, like grinding down high spots. I use an old shop vac tank as a pre-filter to help the dust and larger stuff drop out.
     
  14. Jul 30, 2019 #14

    Ernesto

    Ernesto

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    The paper ones tear easily, that's why I use the cloth ones. Here's a video demonstration, albeit not a great one because the demonstration guy didn't snap the clamps down on the two top parts and you can see where a tiny bit of dust got on the back side of the nice clean vac. LOL

     

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