Concrete Saw Cutting: Wet or Dry?
If
using concrete saws is one of the daily tasks for your company, this
decision is an important one. How you cut will have an impact on employee
health as well as project quality, and the aesthetics of the materials
you’re cutting. I’ll present the pros and cons of each cutting
method as I see them, and you can decide which is right for you.
Wet Cutting
Most concrete saws, handheld or otherwise, come stock
with a water option. Tub saws include a water pump, handhelds include
the plumbing for a household hose connection. And wet cutting has benefits:
reduced concrete dust can mean a healthier environment for you and your
employees, and less to clean on the structures around you, where airborne
dust would normally settle. Diamond blades that run wet also tend to last
longer because they stay cooler (even blades designed to run dry can be
run wet, and you’ll see a reduction in wear rate). You also won't
have to change the air filters on your
concrete saw as often, because the water will keep more of the dust
from reaching the air intake.
However, I’ve found that wet cutting can also
be very messy. With water flow on a handheld concrete saw adjusted too
high, you can end up spraying concrete dust-impregnated water all over
your jobsite, creating a much more difficult cleaning job later. Even
at lower water flow you can still end up having to take scrub brushes
and pressure washers to clean nearby structures that have been coated
(and I tell you this from personal experience - the photo above is a project where we spent the better part of a day pressure washing and scrubbing the walls of part the client's home to get the wetted concrete dust off). With that also comes
dumping lots of lubricated dust over the pores of the brick you may
be cutting. The water really helps this dust settle deep into the brick,
making it nearly impossible to remove (I say “nearly impossible”;
someone might be able to do it, but I haven’t figured out how).
The result is cut brick that are two shades lighter than uncut brick,
and the result of that is usually a long discussion with the client.
Dry Cutting
Dry cutting seems to be less popular in recent years.
At a recent jobsite we even had a neighbor call the local health department,
claiming we were creating too much dust. The guy from the health department
was much more reasonable than the client’s neighbor, but we did
end up having to cut wet. Dry cutting can also be messy, dispersing
dust far and wide, covering people and structures. However, I’ve
found that a few seconds with a leaf blower solves that issue. Dry cutting
also presents a hazard for your employees; sucking concrete saw dust
into their lungs for years is sure to cause problems down the road.
However,
cutting dry preserves the look of the material you’re cutting.
Most all of the dust is sent into the air, leaving only a small bit
of dust on the cut material, which again can be cleaned quickly and
effectively with a leaf blower. To address the employee hazard, we like
to use safety gear that includes eye and hearing protection, but more
important for long-term health issues, we use respirators. A simple
half-mask respirator with dual filters provide good airflow and a tight
seal around the mouth and face, preventing ‘blow by’ of
dust around the sides of the mask (this will happen with the cheap paper
dust masks you can find at hardware stores). It keeps the lungs of my
employees pink, and allows us to provide our clients with a better finished
project.
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