Converting gas lawn edger to cement saw?

I have a cement driveway to remove and rather than break it into chunks and pay to haul away I was thinking of grooving it with a cement cutting blade. Then breaking into blocks to make a retaining wall.

I have a 3 HP 3 wheel gas lawn edger. Also have a 5 and 8 HP engines. Basic shop with lathe, mill and welder etc. I could modify it to take either an abrasive concrete cut of wheel or diamond coated steel wheel. The kind available at Home Depot. Wet or Dry? Will cover the blade with safety shield. Have a trailing rudder to ride in the saw kerf for keeping cut straight and not bending the cutoff wheel. I have experience with metal working but not concrete cutting. Opinions and concerns solicited. Thanks, Scott

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Unless you've got time on your hands and/or you're contemplating this project just for fun, save the resources you would have spent and go down to your local rental outfit and get a concrete saw. Actually, go down and look at them whether you try to make your own or not. The first thing you'll notice is that they're big heavy units, and one large enough to handle an entire driveway will be at least 16hp, and spin something like a 18" diamond blade. To chunk up an entire driveway into blocks would take a stack of abrasive blades as tall as you are.

When you rent a concrete cutter with a diamond blade, they will measure the OD of the blade with a micrometer setup, and when you return it they measure again, and you'll be charged by the .001" for the amount of wear. You don't want to know what an entire blade costs. For this reason, be sure to keep water on the blade (or they burn up, and you'll find out what they cost in an intimate and unpleasant way), and don't cut deep enough to get into the mud below the concrete, which is harder on the blade than the concrete is (go figure).

Before you do any of this, you might want to get an old Skilsaw, and buy a concrete abrasive blade for it. Find an expendable spot on the concrete, and try a cut. This will tell you a few things:

-How fast abrasive concrete blades go away.

-How much work it is to cut up concrete.

-How wonderful concrete dust feels in your pores, shorts and ears.

The rental cutter will, of course, have it's own drive, and will have water to carry most of the dust away (concrete *mud* in your pores instead of dust), but will more than make up for it by being a big, heavy beast to manhandle into position for the next cut.

One final thought: Since you can't cut all the way through the concrete or you'll really wear your blade quickly, you'll still have to break up the concrete blocks a bit. They won't break perfectly straight, so you'll be left with jagged edges that will need to be busted off by hand (with a cold chisel and hammer) before the blocks would stack straight.

Cheers, Walt

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If there's reinforcing wire in the concrete it just isn't worth trying to cut or break it into clean small chunks to make a wall. Cheaper to get rid of it and buy blocks.

If there's no wire, scoring and breaking may actually work OK. Lift up a corner with a hydraulic jack or whatever, slide something under the edge a couple feet back and it may break pretty easily. Esp. if scored.

I don't think you'll get far with a dry-cut blade.

Any kind of heavy equipment like a backhoe or excavator can lift and break it into larger chunks pretty quick.

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Bob Powell


Renting the right machine is my recommendation too, although if you really want to use a Skilsaw or homebrew conversion, pick up a 7.25" diamond blade and try that out. Home Depot has 'em for about $15 (and I recently noticed a few other brands), and they do a great job, certainly far better than any composition blade I've ever tried.

But the rental water-cooled saw will give you *much* better dust control, and it's worth it on that basis alone.


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Pete Bergstrom

Sorry but I have this mindset...Explosives!! But I want to watch.

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Tom Gardner

I agree with the others. Most concrete saws are 16 to 20 hp and the machines are rather heavy and massive. Gary Brady Austin, TX

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Gary Brady

On Wed, 21 Apr 2004 18:16:26 GMT, "Tom Gardner" vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

You're gunna DIE one day, watching all this stuff, Tom!

**************************************************** I went on a guided tour not long ago.The guide got us lost. He was a non-compass mentor.........sorry I'm not.
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Old Nick

On Wed, 21 Apr 2004 18:16:26 GMT, "Tom Gardner" brought forth from the murky depths:

Sounds like a good reason for a tailgate party!

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Larry Jaques

But he'd much rather die doing it than watching it. :)


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Tim Williams

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