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-   -   sawing concrete block: concrete saw or masonary blade? (http://www.diychatroom.com/f105/sawing-concrete-block-concrete-saw-masonary-blade-142991/)

itsnotrequired 05-07-2012 09:47 AM

sawing concrete block: concrete saw or masonary blade?
 
building a concrete block retaining wall for a window well. wanted to get some opinions on the best way to cut the block. this is a block material, not brick (see page 4 of pdf link)

http://www.countymaterials.com/produ...ethod=download

weighing the options of renting a concrete saw or getting a masonry blade for a circular saw. pros/cons as i see it:

concrete saw:
pros:
- deeper blade, more powerful/faster cut
- not beating up my own equipment
cons:
- may feel need to rush job, to avoid another day of saw rental
- rental cost

masonry blade:
pros:
- work at my own pace
- cheaper than rental (maybe?)
cons:
- seems more tedious
- dust fouling my saw

thoughts? i figure if i have a good plan in place, i can get through the sawing in a day and go with the rental. looking to cut about 14 blocks and maybe 12 cap stones.

joecaption 05-07-2012 10:06 AM

We have knowing exactly what your doing, but most of the time if I have a small job I just use a brick chisle and maul to score some lines and the block or cap stone just snaps off along the line.
I've even done those 4" thick curved retainng wall blocks with no trouble.

itsnotrequired 05-07-2012 10:29 AM

this is block, not brick. i have concerns that the block won't break as cleanly as brick would. or doesn't it really matter?

joecaption 05-07-2012 10:42 AM

Try one and see what happens, only time I've had trouble is if it needs to be cut near the parts between the webs.
I score it on both sides.
I find it works best for me to start the two ends first. That way there's a smooth looking part where it can be seen and the cuts are in the field.
You can also buy 1/2 blocks.
Wait until some of the full time masons chime in later in the day. There going to have some great ideas.

concretemasonry 05-07-2012 11:27 AM

From the site posted, it is difficult to determine which products you are using and there may also be some smaller units that were not shown on the site.

Most of the 4 major brands of retaining wall units can be sawed or split. The County units apparently use pins, which require the problems associated with the exact location of the pins in a set-back system. - That is reason the 4 major systems have gotten away from pinned systems and gone to shear lugs that provide the same strength without the "zipper" problems associated with pins (especially with geo-grid). I think I have seen some County units that also are not pinned but the world of "knock-off" products has many options.

If you have a set-back gravity wall with inside or outside curves, you can really only cut as the wall is built, so your wall construction rate will dictate the cutting/shaping. With the vertical beveled edges/corners, sawing is preferential, while with the rustic/tumbled units spliiting can be acceptible.

For cap units a saw is best, especially with a set back wall since any curved corners have a radius that changes every course and you woulf end up cutting the units to exact width for the front and back because the top is exposed.

For those County units, I would suggest sawing and not splitting even for the rustic type units, although splitting the concrete units is more predictable than clay.

Dick

Clutchcargo 05-07-2012 11:35 AM

I cut standard 8x8x16 blocks with my circular saw. It worked out fine and I got a clean cut. it took two passes, one on each side. I do have a separate saw that I don't really like and use that one when making these types of cuts.
Rentals usually don't work for me either because of the time constraint.

itsnotrequired 05-07-2012 12:04 PM

Quote:

Originally Posted by concretemasonry (Post 916481)
From the site posted, it is difficult to determine which products you are using and there may also be some smaller units that were not shown on the site.

Most of the 4 major brands of retaining wall units can be sawed or split. The County units apparently use pins, which require the problems associated with the exact location of the pins in a set-back system. - That is reason the 4 major systems have gotten away from pinned systems and gone to shear lugs that provide the same strength without the "zipper" problems associated with pins (especially with geo-grid). I think I have seen some County units that also are not pinned but the world of "knock-off" products has many options.

If you have a set-back gravity wall with inside or outside curves, you can really only cut as the wall is built, so your wall construction rate will dictate the cutting/shaping. With the vertical beveled edges/corners, sawing is preferential, while with the rustic/tumbled units spliiting can be acceptible.

For cap units a saw is best, especially with a set back wall since any curved corners have a radius that changes every course and you woulf end up cutting the units to exact width for the front and back because the top is exposed.

For those County units, I would suggest sawing and not splitting even for the rustic type units, although splitting the concrete units is more predictable than clay.

Dick

i am using the County 'standard' 12" wide block. i chose them because it matches what is already installed at my place.

interesting comment on the pins. can you elaborate who the 'four majors' are? i am curious how they compare. the county system uses pins that are set in the straight grooves at the top of a given block, with the pins in holes on the bottom of the tier above. seems like corners won't be a problem but please link to some stuff on these shear lugs used by other manufacturers.

you hit the nail on the head with cutting as the wall is built. this is a window well configuration and the idea is that the wall face which is parallel to the window will be built such that the blocks alternate joints evenly as the wall as built up. where it curves around to the foundation wall, the blocks will simply be cut wherever they need to be to match. seems the simplest way to get a nicely patterned parallel face without having to deal with radius changes as the wall is built due to the setback on each tier. so if i can't finish the wall by the end of the day, i have to pay for another rental day.

any opinion on how a concrete saw compares to a masonry blade on a circular saw? does it cut easier/faster with one or the other?

concretemasonry 05-07-2012 12:54 PM

The 4 major systems are Allan Block, Anchor Wall Systems, Keystone and Versalok. Most make some block in local plants, but generally they license the production of their products domestically and internationally in addition to providing technical support, design code approvals and some advertising. County is just a local WI/IL produder.

As long as you have set-back, a radius for a curve will change with every course and it can be a problem for cap units that where the tops are seen.

jomama45 05-07-2012 10:27 PM

I've done a lot of Versa-Lok walls through the years, which are non-cavity, completely solid block, and the only way to realistically alter them is with a handheld concrete saw or a large wall unit splitter. As for the one's in our link, they may saw easier with a smaller circular saw, as long as you only need to take small amounts off of the edges. Not sure how strong those block would be if you ended up cutting off one of the end webs either..........

As for the rate of cut, I'd put a 14" gas cut-off saw with the correct diamond blade at 10-15 times faster than a circular saw with 7" diamond blade, although it could be an even farther spread than that.......

itsnotrequired 05-07-2012 11:11 PM

thanks for all the feedback. i was always leaning toward the saw rental and your comments have reinforced the idea. just need to have some good weather and a good plan in place.

TRUEPRO 05-08-2012 09:05 AM

Quote:

Originally Posted by jomama45 (Post 916851)
I've done a lot of Versa-Lok walls through the years, which are non-cavity, completely solid block, and the only way to realistically alter them is with a handheld concrete saw or a large wall unit splitter. As for the one's in our link, they may saw easier with a smaller circular saw, as long as you only need to take small amounts off of the edges. Not sure how strong those block would be if you ended up cutting off one of the end webs either..........

As for the rate of cut, I'd put a 14" gas cut-off saw with the correct diamond blade at 10-15 times faster than a circular saw with 7" diamond blade, although it could be an even farther spread than that.......

This is the only way to go. Please dont waste your time with a circular saw.


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