I am about to do the epoxy finish on my garage floor, and I have a
question about the acid used during the etching process. Basically, my
dilemma is this: About 15-20 feet from the bottom of my driveway, there is
a 8-12ft diameter perpetual puddle that is consistenly fed by rain and all
of my neighbors' sprinkler runoff. This puddle is used by the local
wildlife (birds, etc) all the time. This puddle is also where my runoff
will go when I rinse the acid from the floor after etching. Now, I'm not
interested in killing/harming/whatever all of the animals that use this
puddle, so my question is this: is the acid nuetralized or anything after
the use on the garage floor, or would it still be toxic? My thought would
be to use a push broom/squeegee to get this puddle moving and the area
rinsed after acid exposure if I have to.
Any input would be appreciated (particularly if you are a chemist! ;p)
It's only a guess (an intelligent one, I hope; I wouldn't call myself a
chemist, although I've studied a fair bit of chemistry in my time and
have worked in laboratories), but I would say that by the time the acid
is done with the garage floor it's no longer going to be acidic -- but
that's no guarantee that the products of the chemical reaction won't
harm the wildlife.
By far the safest would be to get the stuff out of that local watering
hole as soon as possible.
On 09/17/04 12:31 pm Bill Lewis put fingers to keyboard and launched the
following message into cyberspace:
That's what I would do as well Bill. Throw a box or two of Baking Soda on
the area after you sweep the puddle out to neutralize the acid if you want.
Baking Soda is a base and it will neutralize the acid. Water is neutral
itself (neither acid nor base) and it can be used to neutralize the acid but
it will take more of a flush with just water than if you throw a little
baking soda to it. I'd sprinkle a box or two on the swept out puddle, sweep
it around a bit and then flush it well with water. Should be fine after
The acid you use for etching cement is probably HCl, which ought to react with
cement to produce mostly calcium cloride (a salt) and free hydrogen.
Nuetralizing the excess using backing soda, (sodium bicarbonate) should
produce sodium cloride, (table salt) more calcium cloride, and some free gasses.
The runoff will be salty water.
You might get high enough concentrations so to make it unpalatable
to wildlife, but you're unlikely to actually harm anything that doesn't
LIVE in the puddle. If you've got frogs in there, you might get high
enough concentrations to croak them.
On Fri, 17 Sep 2004 13:12:31 -0400, someone wrote:
first, and let the acid wash run into it (far away from where on is
standing)? I'd generally not want to stand there and pour a base into
an acid without a protective suit, but OK maybe its so dilute that
its just a theory, but as a general principal....
Muriatic acid is basically concentrated "stomach digestive acid". Its
toxicity and acidity is a strong function of dilution. Basically, wash
things down with water and you'll dilute it very quickly to the point
that it's no danger to anything. When you dilute it to the point that
you're satisfied, it will be weaker than vinegar.
My opinion is that if it's strong enough to be dangerous, the fumes
will keep any critters away. If it's weak it will taste as extremely
And concrete is a base, right? Eventually the base should neutralize
the acid if it just sits there anyway.
On Fri, 17 Sep 2004 12:31:02 -0400, "Bill Lewis"
A little off topic, but kind of similar...
If your garage floor has some old oil stains (from the previous owner's
car), will this epoxy treatment still work? I've been wanting to do this as
well, but I fear the oil will cause a big mess by not allowing the epoxy to
You'll need to clean up the old oil before you epoxy the floor. Try some
lacquer thinner, paint thinner or like solvent and wipe it up. Don't just
pour some on and let it evaporate. You might have to hit it a couple or a
few times, but you should get it clean that way. Use an old toothbrush to
get it good and clean. After that you should be able to hit it with the
acid and paint to your heart's content. You might see residual stains after
you clean it up but if you washed the area well with solvents, the stains
(discoloration) should not pose a problem.
Isn't it muriatic acid that is typically used to prep the floor? I believe
Rustoleum uses a bit milder acid by using a citric solution. What does the
manufacturer suggest to clean the acid from the floor prior to painting? The
acid has to be gone for the paint to stick. Seems like the same procedure
would work in the puddle.
Hi Bill, I used muratic acid, which is also what's used in swimming
pools. Diluted, it wouldn't be a problem. When I did mine, I just
cleaned the concrete well and mopped on the muratic acid after it was
dry. I only put on enough to wet it and let it dry. I never rinsed it.
The paint has held up about as good as the job I did painting it. I'm
just wondering if you need to put on enough to produce enough to have
to squeegee it. Sorry to attempt to answer your question with another
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