9” angle grinder or concrete saw?

[ive]

Hi all.

Have to cut through some cinderblocks in the basement to open up a door.

I have two vertical cuts to make on both the sides and a two horizontal cuts up top.

Should I use a 9” grinder with a 10” masonry blade or rent a gas powered concrete saw? What’s easier?

Thanks for the input.

 

[Mr.N]

Hi all.

Have to cut through some cinderblocks in the basement to open up a door.

I have two vertical cuts to make on both the sides and a two horizontal cuts up top.

Should I use a 9” grinder with a 10” masonry blade or rent a gas powered concrete saw? What’s easier?

Thanks for the input.

7" diamond blade on a cheap skill saw, cut from both sides.

 

[The Cobbler]

larger the saw the heavier it is.
if you get into a core of the block you need a few inches at most depth of cut .
if you hit a web ( which is very likely you will) you need deeper but it would be easier to just cut in from the edge and cut it out . I think a 6" would be more than enough . 5" might even do it with a few smacks from a club hammer

edit. I see you're making horizontal cuts too, I still think you can do it with a smaller cutoff wheel. I have

 

[KnurledNut]

Ive used a Husqvarna Cut-n-break saw for a similar application. I highly recommend renting this if its available.

 

[tarmy]

I have used both...on cinder block...if no concrete fill in it...use the grinder with a diamond blade, be prepared to cover your mouth and eyes from flying dust.

If concrete filled...rent...

 

[Aquamoose]

Rent it. It’s faster, cleaner, and cuts deeper. Those saws have water hose attachment to kick down the dust & lubricates. Lord knows you want that!


Sent from my iPhone using Tapatalk

 

[may0naise]

A gas saw can be run wet. Which while muddy. Is still way nicer than the dust from dry cutting. Also homedepot rents a hilti gas powered light weight 12" (4" depth of cut) saw that is not THAT heavy. I would get that. Also electric saws or a big grinder with a big blade tend to be massive breaker trippers. So u really cannot cut full depth like u can with a gas saw.

 

[ive]

Hi guys.

Thanks for the input.

A question I have is the gas powered concrete saw gonna a be hard to hold/heavy for the vertical cuts of the wall?

 

[Retroman]

Be careful with a gas saw indoors especially a two stroke, carbon monoxide poisoning will leave you with a nasty headache. Are you putting a larger door in or just a bigger opening? How much are you removing? you will be better off staying in the end of the blocks or the web in the middle of the block there will be vertical rebar typically in each cell on either side of the opening and a piece or two of rebar horizontally above the opening (Bond Beam) you don't want to try and rip a piece of rebar. Yes the gas cut off saws get very heavy especially on the horizontal cuts. for the top cuts I would suggest a skill saw with a dry diamond blade you will want to cut going backwards with the skill saw since the blade spins upward otherwise your fighting the blade as well as the wall. I would suggest you call a concrete cutting company and get a price on the cutting you can do the demo and removal. This is a job where the right tools make all the difference.

 

[Mr.N]

Rent it. It’s faster, cleaner, and cuts deeper. Those saws have water hose attachment to kick down the dust & lubricates. Lord knows you want that!

Yes the dust *****!
However, the slurry of water and concrete is considered toxic waste. You need to buy a harder for it.

I've used a 14" gas saw, 12" electric saw, 7" skill saw, and a concrete hole saw up to 4". I've used a concrete planer (scarifier), a concrete grinder with 30 grit diamond dots all the way to polish.

First and foremost, use a diamond blade and not an abrasive blade. (Made that mistake when trying to save money and cut deep on a 9" grinder)

For a homeowner and one job use go with a cheap 7" skill saw and have someone lightly spray water on the blade from a hose.
Get good ear plugs and something to collect the slurry. A chisel and hammer can finish of the block if the depth doesn't cut it all.

 

[dogdog]

Hi guys.

Thanks for the input.

A question I have is the gas powered concrete saw gonna a be hard to hold/heavy for the vertical cuts of the wall?

Small job, I have used the 7" / 9" / 4.5 grinder... bigger job I have used the 14" stihl gas powered saw... dependents on the cutting depth.. of that concrete..

both times, I have some one holding a small hose with running aiming at the saw... the times I couldn't let's say dust clouds everywhere...

maybe you can get away with just a 9" grinder... if you only have few cuts...


Mayabe drill 4 holes all the way through as reference... and cut on both side , break them with a BFH and patch up nicely with concrete ? It can be done ... just keep in mind about the cutting depth of your cutting disc.....

Gas power saw can be dangerous if you have not hold one before and working vertical position... or at least if you are not as physical strong as you once were otherwise it's just a bit heavier than the larger chain saws... well at least the stihl 420 I have is that way... not sure ...

 

[rustyjames]

Definitely, you'll want to use a water mist making those cuts. Most concrete cutting saws have a garden hose connection for that purpose. There are also electric saws with dust collection systems.

 

[tarbellb]

Yes the dust *****!
However, the slurry of water and concrete is considered toxic waste. You need to buy a harder for it.

I've used a 14" gas saw, 12" electric saw, 7" skill saw, and a concrete hole saw up to 4". I've used a concrete planer (scarifier), a concrete grinder with 30 grit diamond dots all the way to polish.

First and foremost, use a diamond blade and not an abrasive blade. (Made that mistake when trying to save money and cut deep on a 9" grinder)

For a homeowner and one job use go with a cheap 7" skill saw and have someone lightly spray water on the blade from a hose.
Get good ear plugs and something to collect the slurry. A chisel and hammer can finish of the block if the depth doesn't cut it all.

My money would be on this guy^^^^

Skil saw with diamond blades is super light and maneuverable for overhead work. Cheap to buy/rent, blades are also cheap. And you friend with the squirt bottle wont be full pucker.

If you go gas, BE SURE TO USE VENTILATION.

 

[fourjeepin]

I bought the 9” harbor freight grinder for a one time use project (foundation vents) and have used it many times. It probably cost what a one day rental would be. Far from the best available, but it does the job.

 

[ItsNemo]

Grinders are weak for concrete cutting, even my 7" is kind of sad...I'd go with a 12+ inch proper concrete saw.

 

[dogdog]

Nope gotta get the right blade... Just cut up a concrete bathroom floor that is about 2"-ish thick with tiles on top... like butter on the 4.5 grinder with a 5" blade, no guard ... but because it's electric and not water proof... lets say dust are all over but cuts like butter for $40/10pk and only have used 1/2 of it's life . But I did use the Dewalt industrial version of the grinder ( yea dewalt have different version of the same look alike grinder)... I have cut 5" concretes with a 7" HF grinder and a 6" Dewalt blade... those blade makes a huge differences.

 

[ItsNemo]

Nope gotta get the right blade... Just cut up a concrete bathroom floor that is about 2"-ish thick with tiles on top... like butter on the 4.5 grinder with a 5" blade, no guard ... but because it's electric and not water proof... lets say dust are all over but cuts like butter for $40/10pk and only have used 1/2 of it's life . But I did use the Dewalt industrial version of the grinder ( yea dewalt have different version of the same look alike grinder)... I have cut 5" concretes with a 7" HF grinder and a 6" Dewalt blade... those blade makes a huge differences.

Which specific blades do you use? I have the Dewalt DWE4597N which is not exactly a wimpy 7" grinder (it's actually stupidly powerful), works great with grinding wheels or flap discs, but I've never found a good concrete cutting wheel for it.

Sure would be easier to use that from time to time instead of my 12" electric (just the evolution one) that needs 20a.

 

[dogdog]

Which specific blades do you use? I have the Dewalt DWE4597N which is not exactly a wimpy 7" grinder (it's actually stupidly powerful), works great with grinding wheels or flap discs, but I've never found a good concrete cutting wheel for it.

Sure would be easier to use that from time to time instead of my 12" electric (just the evolution one) that needs 20a.

will take a pic tomorrow... It's some grinite blade I got on ebay for like $20-$40 (don't remember the bidding) or something pack of 10... though it was ****.. but really surprised me.

I can't find the link any more from ebay but it looked like this also green ...

https://www.ebay.com/itm/5-Inch-GRE...ade-SUPER-Granite-Concrete-Stone/302597351043


Found the order... purchased 9/21/2017 $29.27 winning bid, don't remember the shipping cost....

if I search GranQuartz 698855

"Lot of 8 GranQuartz 698855 Recon Dry Cutting Saw Blades, 6" D x .090" T x 7/8" A"

https://www.granquartz.com/stone-fabrication/blades/6-recon-granite-turbo-blade-7-8-dko-5-8-arbor

and ouch... $40 per blade they are selling... Guess I got a good deal on that bid.

will attach the pics tomorrow.

 

[dogdog]

here attached pics of most of my smaller concrete blades, less of the 10" or 14" ones... those are something less less of the 7" 9" grinders... mix of HF and Dewalt...