Pool Shock is a very strong oxidizer. If it comes in contact with petrolium
based product it will spontaneously combust. I know someone who was severely
burned by mixing granulated pool chlorine and gasoline. She was trying to
clean oil stains from a driveway. Also #1 son mixed it with used motor oil.
Not fire but a lot of smoke in the garage. Neighbors called Fire Department.



"David Combs" wrote in message
...
mold on outdoor concrete-stairs: chlorox vs "shock"(???)

(plus aluminum siding, too)

Thanks for the suggestions for getting the mold off the
aluminum siding.

Just this afternoon, I finally got around to doing a
use-laundry-bleach test:

The Chlorox (100%) [as advised to me in
a respose to a prior post here, re mold and aluminum
siding] did indeed "pretty-much" work on that
siding, in that it lightened the mold as well as made
it fairly easily to rub-off.

The color that remained underneath looked like a mix of maybe 2/3
original-white and 1/3 ugly-grey.

(I suppose that's as good as it will get?)

----- outdoor concrete-stairs: mold stuck-HARD to them:

I also squirted that 100% laundry-bleach on some nearby shaded
outdoor-stairs made of
somewhat-rough-surfaced concrete, the result being a *total
failure* -- it wasn't the least bit easier to
scrape off the mold -- in fact I still couldn't get
*any* off.

(The roughness really gives it a grip, huh?)

----- "Pool Shock"(?) (swimming-pool chlorine):

Now, here's something interesting that I recently found
searching back to a much-earlier repair-thread, about someone needing
to clean mold from his concrete driveway.

The final suggestions he got were between using plain laundry-bleach,
vs using a special for-swimming-pools chlorine,
something they referred to as "pool shock", that came in a
powder form (to mix with water, I suppose).

("Pool Shock" -- why that name? Trademark or something?
What does it mean? And, is it called that everywhere
in the U.S., or just in some local areas?)

---- Here it is:

Mix household bleach (one gallon) with one pound of swimming
pool chlorine and 3 gallons of very hot water in a 5
gal. bucket. Stir well - use broom to coat driveway. Do this
on a hot day and let it dry. 3 hours later hose off. You'll be
very pleased with the results.
#
While I'm sure this will work, what is the purpose of mixing weak
bleach aka Clorox with strong bleach aka pool shock? Just mix
the shock in water. A 1 lb bag of shock is enough to give you
10ppm in 10-15,000 gallons so it will make a hell of a strong
brew in a 5 gallon bucket.

So, what opinion on *this* approach? Pros and cons?



----- Hey -- what about using it for the siding, too?

And -- supposing that someone here will suggest that I
use this stronger stuff on those stairs (to "shock"
away the mold?), what advice about using it on the aluminum
siding too? What chance that the result there would be
any better than what I got with the chlorox? (or any worse?)

Likewise, since I assume I'll be using a (rented)
"pressure washer"
to remove the (hopefully by-then-weakened) mold

Now, would that "shock" stuff make it any easier for a "pressure washer"
to wash off the (weakened) mold?

---- Also, what *kind* of pressure-washer to rent?

(Note: due to that large slope
(at the front of house, the yard is level with of
first-floor, but at the rear, it's an entire floor
lower, at basement level, making the 2nd floor
*three* floors up)
I'll have pressure-shoot the water up as much as 30 feet.)


(1) Gasoline, I suppose (assuming they rent out the things).

(2) What level of "psi", and what horsepower, would I need?

(and what would be the bare minimum?)


Thanks!

David