On Wed, 13 Nov 2013 13:10:19 -0500, Ed Pawlowski wrote:
For some reason, unbeknownst to me, all my refrigerators
that are turned off, develop a funky black mold.
What the mold is eating, is beyond me, as they are on
the white plastic.
I do not know how to PREVENT that black mold, since,
the only way I know to prevent it is to run the frig.
Anyone have advice on that?
Funny you mention those two preventive measures, since
I *do* usually keep the door open (which vastly reduces
the black-on-white spots) ...
And, when it's time to use the frig, I do use bleach.
It would just be nice if I could figure out what the
heck that black mold is eating since I didn't think
mold eats plastic.
I don't see any problem leaving a fridge in cold storage.
Let it warm up for a day or two before running it because the oil in the
compressor needs to be at room temperature before it will properly
Mold will try to grow wherever there is moisture and a source of food.
In the corner of a building my father owned, there would often be mold
growing on the inside walls, and it was because the lousy architect that
designed that building put closets in the 4 corners of the building.
So, with the closet door closed, there wasn't as much heat getting into
the closet, and those corners could lose heat in two directions at once,
so the walls there were always cold in the winter and mildew grew on
Mildew needs food to GROW. However, it can remain dormant for years if
there's a lack of food or water. The food available in the subject
closet is simply airborne dust particles.
A lot of dust consists of cellulose. The reason why it's always dusty
under a bed is because cotton and linen are both almost pure cellulose.
Wood is mostly cellulose, and so paper fibers are also mostly cellulose.
That's why it's always dusty around and under your toilet paper
dispenser, too. Cellulose is a form of sugar, just like starch. Water
from the roots, CO2 from the air and light from the Sun all combine in a
plant's leaves to form sugar molecules, or "glucose". Mmost people are
unaware of the fact that there are two kinds of glucose molecules. They
both have exactly the same number and kinds of atoms, it's just that
those atoms are arranged slightly differently. Chemists call molecules
like that "isomers". For simplicity, we'll call them Sugar A and Sugar
If you stack up Sugar A molecules like bricks in a wall, you get starch,
which is what potatoes and rice and pasta are made of. If you stack up
Sugar B molecules like bricks in a wall, you get cellulose, which is
what wood, paper, cotton and good quality cleaning sponges are made of.
The enzymes in people's stomach have the ability to break down starch
into it's constituent sugar molecules, but not cellulose. That's why
our blood sugar level goes up a lot faster if we eat a plate of
spaghetti than it does if we eat a plate of broccoli. However, the wood
rot fungus, all grazing animals like cows, and some other organisms have
the ability to break down cellulose into it's constituant sugar
The mildew growing in your fridge and on the cold walls of your house
(like unfinished concrete basement walls) are feeding on the cellulose
dust that's floating in the air and sticking to the damp walls. (See PS
When walls get dirty lines over the wall studs or ceiling joists, people
often attribute that to airborne dust and soot particles sticking to
tiny droplets of moisture that form over the studs or joists because
wood's R value is only 1, whereas fiberglass insulation is 3.5 per inch.
So, the wall surface over a stud is going to be colder that that
between studs. However, what's actually happening is that that
accumulation of dust and soot in straight lines on the wall or ceilings
is quantum mechanics in action.
If we bounce a ball against a wall, the ball behaves entirely due to
Newtonian mechanics, and Newtonian mechanics doesn't consider whether
the wall is hot or cold. Neither does relativity. As your particle
size becomes progressively smaller, the physics of every day objects
starts to follow more and more the laws of quantum mechanics rather than
Newtonian mechanics. In quantum mechanics, the colder the wall, the
more energy the ball will lose when it comes into contact with the wall,
and the slower the ball will be moving as it bounces off the wall. And,
given repeated impacts with a cold wall, a speck of dust or a particle
of soot, like a Buckyball, will loose enough energy to stop moving
altogether. In that case, the speck of dust or particle of soot will
simply remain in contact with the wall. As those specks of dust and
particles of soot accumulate, we start to see dark lines forming over
the studs and ceiling joists, and even darker circles forming over the
drywall screws in the studs and joists. People often mistakenly
conclude that the dust or soot is simply sticking to tiny droplets of
water that have condensed on the cooler surfaces of the drywall, but
this can't be true. You can float a razor blade on the surface of a
glass of water because water molecules attract one another. That
attraction gives rise to surface tension in the water, and that surface
tension would prevent the speck of dust or particle of soot from
actually penetrating into the water. Beach sand sticks to wet feet
because both the sand is wet and the skin is wet and the water molecules
on both attract each other. The water wouldn't actually wet the surface
of the tiny particles coming in contact with the wall that have
virtually no energy. If anything, those particles would bounce off any
water surface they come into contact with. What you see on the dirty
walls of a smoker's house is proof that quantum mechanics isn't just
something that happens in particle accelerators, but is active in our
every day lives as well.
On Wed, 13 Nov 2013 22:19:19 +0100, nestork wrote:
Must be that which makes the black mold on a frig then!
I guess the OP might be in a quandary though, since opening the door
will keep the frig dry, but will probably add dust.
Closing the door will keep the dust out but it will probably be
Dunno how to get the frig to be *both* dry and free of dust in
Very interesting and likely valid dissertation by Nestork on dust and what
he calls quantum mechanics. However, I beleive it falls short on his
dismissal of moisture and wet surfaces as a contributor to incresing the
attraction of dust to surfaces. Consider for instance confetti or small
shreds or pieces of tissue paper. It's easily observable that they will
more readily stick to a damp surface than a dry one.
There are no stupid questions, but there are lots of stupid answers.
Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar. org
In my last post, I presumed that cellulostic dust would be affected by
quantum effects, but I think that was a mistake. Dust particles are big
enough that you can see light reflect off them in a sunbeam. That's far
too big for quantum effects to be significant. Also, in my building
I've only seen vertical lines form on exterior walls when suites were
occupied by smokers or people that liked to burn candles or incense.
I've been living in my own apartment for over 25 years without once
having cleaned the walls, and yet there are not dark lines over the
studs in my exterior walls, just as there aren't in any of my apartments
since I adopted a no smoking, candles or incense policy.
Cellulostic dust is what provides the food source for mildew that grows
on wet, cold and damp surfaces in your house, but I think dust particles
would be far too large to be affected by quantum mechanical effects that
I talked about. Dust particles are so large that you can almost see
them. When you see a beam of sunlight coming in through a window, you
can identify individual dust particles floating in the air by the
sunlight that reflects off of those dust particles. To get the
particles to "stick to" cold spots on walls, you need vastly smaller
particles before quantum mechanics comes into play.
The dark lines that form over wall studs and ceiling joists and the dark
spots that form over the heads of drywall screws aren't caused by dust.
Those are caused by soot particles in the air, like buckyballs, that are
the size of large molecules, and therefore vastly smaller than dust
particles. Soot particles are produced by smoking cigarettes, burning
candles or incense or perhaps burning toast in the toaster. Soot
particles are affected by quantum mechanical effects very much more than
dust particles because of their size.
Soot particles are clumps of carbon atoms. They are not polar like
water is. That is, they would not be attracted to water, and H2O
molecules would not be attracted to them.
By contrast, cellulose consists of polar sugar molecules. Water
molecules are also polar, and so there is an attraction between water
molecules and cellulose (or sugar). This is what makes sugar so soluble
in water, and it's why water will be absorbe into a cotton shirt, a
piece of paper or a piece of wood rather than bead up like it would if
you put a drop of water on wax paper.
So, I could see that there would be an attraction between cellulostic
dust and tiny droplets of condensation over the colder parts of a wall
However, the dark lines that form over wall studs and ceiling joists are
not from dust accumulation, but from soot accumulation. And soot
particles aren't polar. They're not attracted to water in the
Here's a picture of a miniature robot resting on the surface tension of
Here are two paperclips and a pin doing the same:
Now, all of these objects are made of metals which aren't polar either.
Here, there is negligible attraction of the water to the metal, so the
surface tension created by attraction between water molecules is
sufficiently strong to prevent the metal object from breaking the
surface of the water and sinking. You couldn't do the same thing with a
piece of paper because the water would be absorbed into the paper
because of the attraction between polar molecules. You'd end up with a
wet piece of paper inside the water, perhaps sinking or perhaps floating
just under the water's surface.
Why would a soot particle, which is just a clump of nonpolar carbon
atoms, coming into contact with the surface of a droplet of condensation
behave any differently than the metal objects? The surface tension on
the surface of a microscopic droplet of condensation is just as strong
as it is in a glass of water. If a steel paper clip weighing a billion
times more than a soot particle doesn't break the surface tension of the
water, how could a soot particle do it?
It would seem to me that a non-polar soot particle would either bounce
off the surface of the water, or come to rest on it's surface if the
water absorbed all the kinetic energy of the soot particle. But, that
means you don't need the presence of water for the soot to accumulate.
A cold DRY wall will absorb kinetic energy from the soot particle as
readily as cold water will. You just need cold temperatures at the
surface of the wall or ceiling for soot to accumulate on those cold
surfaces. And, the fact that the soot accumulates on cold dry surfaces
instead of warm dry surfaces proves the existance of quantum effects,
not the existance of microscopically small droplets of condensation.
Check this out
If you clean it and dry it thoroughly on a hot day,
when the inside gets below the dew point, moisture
settles on the surface.
With the calculator, set up the temperature and relative
humidity on hot day. Vary the dials to change the inside
temperature and relative humidity to keep the dew point the
same. The charts on the right will tell you if you're
likely to grow mold.
Solution is to use dehumidifier stuff like they sell
for RV's and leave the door shut.
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