Grinder and speed to cut an edge on concrete

[JHZR2]

Ive got a concrete lip thats a few inches high, that I'd like to cut a 45 degree or so ramp into it. Essentially cut off the 90 degree corner. How much of the 90 degree is removed does not matter too much; I don't need to remove so much that the "ramp" is flush with the lower surface.

I think I need to use an angle grinder to do it. A diamond blade and perhaps a diamond cup should get me a smooth result, right?

I have a 4.5" grinder, is there any necessity to going bigger? Its just a few inches, a very small amount, and Im ok going slow with removal. Should I consider getting a bigger one?

Mine is fixed speed. For a blade or diamond cup, is there any reason to consider variable speed?

Id probably wet the concrete to minimize dust, though ive seen people on youtube doing it dry.

Any other suggestions?

 

[wrcsixeight]

I'd use my Older 7 1/4 inch circular saw with several layers of masking tape on foot, with masonry blade set at 45 degrees run along a straight edge, and a dust mask.

 

[UNC201]

How are you planning to deal with the exposed aggregate though ?

 

[donnyj08]

Do you have a picture? You certainly can use a diamond wheel and a grinder. You can also rent a concrete saw from Home Depot or a rental place if you need to cut a considerable amount out.

 

[yeti]

you don't need any special tools for this. a 4 1/2" angle grinder, and a standard sacrificial masonry wheel is more than enough.
I did a 20' long "shaving" of a driveway curb cut with the tools mentioned, to get rid of a sharp edge that, over time, might be tough on tires. the cut edge was smooth with the standard wheel.
your job is a one beer job.don't overthink it. have a good evening.

 

[JHZR2]

Originally Posted By: chefwong
How are you planning to deal with the exposed aggregate though ?



What difference does it make??

(Thats a serious question)

This isnt a spot where it needs to look anything special.

The simplest analog is if i wanted to cut a curb to have a 45 degree slope downward to the street. Thats not what im doing but its the easiest visualization i can think of.

 

[JHZR2]

Originally Posted By: yeti
you don't need any special tools for this. a 4 1/2" angle grinder, and a standard sacrificial masonry wheel is more than enough.
I did a 20' long "shaving" of a driveway curb cut with the tools mentioned, to get rid of a sharp edge that, over time, might be tough on tires. the cut edge was smooth with the standard wheel.
your job is a one beer job.don't overthink it. have a good evening.


Thats exactly what I figured and more or less what im doing.

So, variable speed or fixed? What wheel is best?

 

[Pop_Rivit]

A grinder with a masonry blade will be fine for a small amount of concrete cutting. Just use whatever you have.

If it's a large amount I'd use a circle saw with a corundum or diamond blade.

 

[ecotourist]

I did a similar job with a (rented) angle grinder and a blade from Home Depot.

I'd mark a line on the concrete (felt marker) and grind up to it. Doing a neat job won't take any longer.

Be sure to wear a really good dust mask. There's bound to be a lot of silica in that concrete. Cutting it wet would be better but may not be practical.

And eye protection. Don't want to spend time in emergency getting debris taken out of an eye.

 

[JC1]

Originally Posted By: wrcsixeight
I'd use my Older 7 1/4 inch circular saw with several layers of masking tape on foot, with masonry blade set at 45 degrees run along a straight edge, and a dust mask.


I think this is a better option. You could also have someone use a hose to wet the blade with a small amount of water to treat it like a wet saw and keep the dust down while you cut the length.

 

[spasm3]

I've done it with a 4 1/2 grinder, works fine. It is hard on your grinder. This is a good place to use a harbor freight grinder. If you will only use it for this job, HF has a diamond cup 4 inch for $20. Home depot as it for $39. If you have a lot to do , the HD will probably be much better.

 

[JHZR2]

I dont have a lot, maybe 18"

 

[spasm3]

Originally Posted By: JHZR2
I dont have a lot, maybe 18"


Just use your grinder then, that's not a lot. If you had like 30ft, i'd not use a good grinder, as the mass of the cup is not good for the bearings.

I used a HF diamond cup it is currently $29 bucks worked well for a one time job. Usually i don't use HF things except for one off jobs where it just makes financial sense.

Here is what i used 29.99 ;

http://www.harborfreight.com/4-in-diamond-turbo-cup-wheel-61416.html $29.99

Here is the HD one. More mass, more cutting area, if you were going to do a lot. $39.99

http://www.homedepot.com/p/RIDGID-4-in-D..._-202884364-_-N

Here are some pics of what i did, several years ago. Its more noticable right after you do it, but after a year, you really can even tell unless you look close, that you ground it down.

The concrete had a bit too much slump and i edged it too early, it migrated against the form leaving an edge. I ground it down easily. I would wear hearing and eye protection. I wore a dusk mask also.

I ground it dry. You could wet it, but i think i will still throw dust as it cuts pretty fast.