wow diamond blades don't last long

[1956chevy210]

So I'm cutting my shop floor and it started out pretty good but now my blade really isn't cutting very fast. My tool is a Bauer 14 inch wet/dry 15A corded masonry saw and my blade is a Hercules All-Cut segmented 14" blade rated four out of 4 "dots" for cured concrete or 3 out of 4 dots for cured concrete with rebar (which my floor has). I'm using water.

After cutting about 30+ linear feet of concrete, the blade definitely slowed down. I tried dressing it using the file method where you ping it with the edge of a ******* file all the way around, and it maybe improved the cutting speed a little bit, but now it is really slow again after another 6-12 feet. Dang, this blade was $85! I'm going to go broke buying blades!

What am I doing wrong? Anything? Is it just the way it is? What's the best way to dress this blade? If I got a dressing stone, how do you keep it steady while you run the hand-held portable saw through it a few times? I saw people dressing masonry blades on youtube, but those were stationary masonry saws with sliding carriers for the workpiece, so it was too easy.

Thanks for reading,

56chev

 

[bluedog225]

I’d be pretty happy to get 30’ out of a blade. Concrete eats stuff. Gets expensive. Curious about how deep the cut. Others who know more about cutting concrete will be along.

 

[PCustoms]

I've never heard of hitting a diamond blade with a file...

What are you cutting your floor for?

How deep?

 

[1956chevy210]

I've never heard of hitting a diamond blade with a file...

What are you cutting your floor for?

How deep?

Yeah apparently it's a thing. You use the edge of the file to tap on the blade to remove glaze and expose the diamonds.

I'm cutting out a section of my floor because it is too thin to install a 2 post lift. 14' by 5'. It's currently about 4 inches thick.

56chev

 

[JohnC1957]

I don't know anything about that saw or that blade I have hired a bunch of concrete cutters and their walk behind saws cut all day with the same blade. I've rented a few gas saws and the blades last all day. Are you cutting wet or dry?

 

[PCustoms]

I don't know anything about that saw or that blade I have hired a bunch of concrete cutters and their walk behind saws cut all day with the same blade. I've rented a few gas saws and the blades last all day. Are you cutting wet or dry?

I'm using water.

 

[whateg01]

(which my floor has). I'm using water.

I don't know anything about that saw or that blade I have hired a bunch of concrete cutters and their walk behind saws cut all day with the same blade. I've rented a few gas saws and the blades last all day. Are you cutting wet or dry?

I'm going to guess that the people doing this every day are not buying their blades at harbor freight. I could be wrong though

 

[Firebrick43]

Cheap blades don't have a lot of diamond nor good bonding to the disc. Industrial grade wheels with the correct coolant can last months of 3 shifts of production work.

 

[finn]

I went back to abrasive blades for cutting concrete. They wear faster, but they’re so cheap that the cost per foot is cheaper, or was last time I used the saw.

Don’t know if they will work for all situations, though.

 

[TurnipTruck]

I was just at the tool rental last week and noticed their concrete saw blades were over $500, and you have to buy the blade when you rent the saw.

 

[1956chevy210]

As an add-on piece of info, I'm cutting about 7 feet at a time (because my 2x8 weighted guide board to help me keep a straight line is about 8 feet long). So I'll make a cut about 1/4" to 1/2 inch deep to score the surface, then go back and go deeper by about 1.5", then another 1.5", and then another cut that makes it all the way through the floor. At least, that was the method yesterday. Cutting is so tough now that I can barely do an inch at a time, and unless I go really slow then the saw climbs up the uncut concrete, so I have to work the saw back and forth to reach the max depth. It's working, but slowly.

56chev

 

[rlitman]

Are you using enough water? Not enough water to keep dust down. That's NOT enough by a long shot, and that creates a slurry that lubricates the blade. Either get a dry cutting blade, or keep the cut absolutely FLUSHED with enough water to wash out anything you've cut.

 

[strength_and_power]

We had to have some concrete panels cut due to a dimension change that wasn’t caught. The guys used a diamond blade until they hit rebar, switched to an abrasive blade to get through the rebar and then would run the diamond blade on a concrete block to deglaze the diamonds and then go back to the cut. It was crude but got the job done.

Other times we’ve had slabs cut, the concrete cutting company’s saw gave zero shits about the rebar, they cut 18’ of 10” slab with set up and tear down in under an hour.

You may get a quote from a cutting company. If you can handle the disposal, the actual cutting may not be too bad. A cash or beer tip may get you a few extra cuts so you can pop the pieces out.

 

[Captain Spaulding]

I have never had good luck with any kind of blade from HF.

 

[BobnCO]

My input as old GC having paid for ample Pro cutters and having my own 14” electric.. Yes hitting a good blade was a very common thing and may bring out rage diamond a bit. Recently my ancient pro blade (probably $300 inflation adjusted dollars in 90’?) seemed slow, and I finally bought a new Diablo? From Home Depot and have been impressed (I never cut a lot). what you describe is that particular brand or blade was just not up to the task. To me the blade at HD seemed cheap because of my historical experience.
Good Luck

 

[Lassen Forge]

If it's a wet or wet/dry blade, you need to make sure you have a metric f***ton of water on that blade, and go SLOW so it doesn't heat up. As in literally a small river of water. The cooler and wetter you keep the blade, the longer your diamond abrasives will last.

We used to also do diamond core drills the same way - we could get days of production out of one, just don't push it to where it gets hot.

95% of everything here is cutting brick, stone, or concrete. We have special dry blades you get at the local big box... usually in 6 or 10 packs. They wear out pretty quick, but still they last more than a week...

 

[jack stand]

I've come a long way appreciating the HF value and warranty, but I'm still very skeptical about any of they're "cutting" tools ie; drill bits and saw blades.
I will say that a recent Hercules miter saw came with a blue herc blade and seems very close to the brand name.
I did see a review about they're blades but the only thing that I positively remember is that they were comparable price to the bigger brands.
It seems that they are taking advantage of the huge price savings across their line hoping the consumer isn't doing the homework.

 

[djbmw]

Yeah apparently it's a thing. You use the edge of the file to tap on the blade to remove glaze and expose the diamonds.

I'm cutting out a section of my floor because it is too thin to install a 2 post lift. 14' by 5'. It's currently about 4 inches thick.

56chev

30 linear feet at 2-4" depth is decent before showing signs of degredation. Why are you using a 14" blade though? Your job doesnt call for such a large (and expensive) blade. A 10" blade, for example, is half the cost of your 14" blade and will do the job just as well. Heck, if your current floor is only 2" thick you could use an angle grinder with 4.5" diamond disks that are $10 each.

 

[txvwnut]

As an add-on piece of info, I'm cutting about 7 feet at a time (because my 2x8 weighted guide board to help me keep a straight line is about 8 feet long). So I'll make a cut about 1/4" to 1/2 inch deep to score the surface, then go back and go deeper by about 1.5", then another 1.5", and then another cut that makes it all the way through the floor. At least, that was the method yesterday. Cutting is so tough now that I can barely do an inch at a time, and unless I go really slow then the saw climbs up the uncut concrete, so I have to work the saw back and forth to reach the max depth. It's working, but slowly.

56chev

By scoring a line instead of getting the blade in to depth you are just knocking cutting abrasive off of a cheap blade. For your depth get the blade in full and get to cutting. As stated earlier water is your blades best friend and the wetter the better as it will keep the blade cool and help flush out the slurry produced from cutting.

 

[matt_i]

There is a reason diamond edge tools aren't used in machining steels...the heat quickly vaporizes the diamonds. I think you are going to have to keep buying wheels or switch to standard wheels to get thru the steel reinforcement. Or work around it/over it until you can get some exposed.

 

[rlitman]

There is a reason diamond edge tools aren't used in machining steels...the heat quickly vaporizes the diamonds. I think you are going to have to keep buying wheels or switch to standard wheels to get thru the steel reinforcement. Or work around it/over it until you can get some exposed.

Steel cutting diamond abrasive wheels have been around for some time. The heat doesn't damage the diamonds! It can dislodge diamonds from a cheaper substrate, but that issue has been solved by many manufacturers, and that's what's got to be going on with a rebar rated wheel. Surface grinders use borazon over diamonds, not because of the heat, but because the carbon in the steel binds to and erodes the diamonds. But that has nothing to do with cutting rocks.

...Why are you using a 14" blade though? Your job doesnt call for such a large (and expensive) blade. A 10" blade, for example, is half the cost of your 14" blade and will do the job just as well. Heck, if your current floor is only 2" thick you could use an angle grinder with 4.5" diamond disks that are $10 each.

That's a false economy. Diamond wheel prices are grounded in the amount of diamond present, and that's based on the circumference. 4.5" diamond discs are cheap, because they don't have a large circumference, so they naturally don't cut as far.

 

[Superbowl]

What? A cheap Chinese diamond saw blade from a store that sells disposable tools doesn't last long! Who would have seen that coming?

 

[PCustoms]

Who would have seen that coming?

Eric Smidt

 

[Mandres]

I have never had good luck with any kind of blade from HF.

I'm wondering if that's the root of the problem. The HF consumables have always had a bad rep.

Maybe try a Diablo blade and see if it holds up better?

 

[tarbellb]

My HF consumable doesnt last long.

OK.

 

[Hohn]

Cheap blades don't have a lot of diamond nor good bonding to the disc. Industrial grade wheels with the correct coolant can last months of 3 shifts of production work.

I'm going to guess that the people doing this every day are not buying their blades at harbor freight. I could be wrong though

I'm not sure that concluding all blades are junk from a sample size of one HF product is valid.

 

[Firebrick43]

I'm not sure that concluding all blades are junk from a sample size of one HF product is valid.

Where did I mention HF? Or a sample size of one?

 

[Hohn]

Where did I mention HF? Or a sample size of one?

Not you, the OP suggested it. You are bang on correct IMO.

I was agreeing with you. But awkwardly

 

[1956chevy210]

30 linear feet at 2-4" depth is decent before showing signs of degredation. Why are you using a 14" blade though? Your job doesnt call for such a large (and expensive) blade. A 10" blade, for example, is half the cost of your 14" blade and will do the job just as well. Heck, if your current floor is only 2" thick you could use an angle grinder with 4.5" diamond disks that are $10 each.

I don't have the whole slab out, but using a wire to check the depth of the cut, it's as shallow as 4" and as deep as 4.5 inches. My 14" blade is rated at 4&9/16" deep, so I doubt a 10" blade would go deep enough. Right?

 

[1956chevy210]

Thanks for the replies everyone. It sounds like the #1 thing I could do different is use a LOT more water. I am using water, hooked directly to the water port on the saw as it should be, but I don't have it on full blast and that likely isn't washing away the slurry enough as several people have said. More water, less slurry, better cut. I'll try it, it's free.

If that doesn't work I might try a Diablo blade from Home Depot. I'll see how it goes.

56chev

 

[rlitman]

Let us know how more water works.

FWIW, I own an ancient AEG 14" electric demolition saw, and it's good for what it is (I've always used it dry with a segmented or turbo blade), but for someone who's used to the power of a gas saw, keep in mind that the electric saws put out about half the horsepower (at half the RPM) to the blade as a gas saw, so the cutting performance is at best so-so.

 

[KnurledNut]

@1956chevy210
Check the blade for a direction arrow and make sure that matches the saw rotation.
That Bauer is not designed to be pushed forward. It’s a pull saw only.
They recommend no more than 2-3/8” initial depth of cut.

 

[djbmw]

I don't have the whole slab out, but using a wire to check the depth of the cut, it's as shallow as 4" and as deep as 4.5 inches. My 14" blade is rated at 4&9/16" deep, so I doubt a 10" blade would go deep enough. Right?

A 10" blade will get you to 3.3" of depth and a 4.5" blade will get almost to 1.5" of depth. I didnt know how deep your floor was currently but assumed it was a shallow pour, which is why you want thicker for the lift pads. However, the blade doesnt have to cut through the entire depth... if you leave a fraction of an inch of depth it will still act as a score line if you hit it with a sledge.

 

[signcrafter]

A good blade will last way way way more then 30 feet. Not sure if it's your HF blade or if something else but I get way more life out of my blades, but they are a few hundred dollars each. I have a 16" husqvarna walk behind saw and two gas stihl cut off saws.

You can try to make a few cuts into a CMU block, I do this for my tile blades. The softer material will wear away the resin bonding and expose fresh diamonds. I've never had to do it with my concrete blades but maybe it will work on yours. Otherwise go spend the money on a good quality blade and get the job done.