I have several cans of paint that I used to paint the rooms (interior latex
paint). I turned them upside down and stored them in the garage. It has
been I think 20 months ago. Today I opened them so I can do some light
touch up work on a few patched up screw holes, I noticed the paint has
turned into hardened cottage cheese. How long are they supposed to last? a
few months? On the other hand, I have the same brand (Benjamin Moore) latex
primer Fresh Start which I bought around the same time, and that was fine.
Am I not storing them right or do these paint have a shorted life span? Yes
I made sure I close the lid tight, and tapped with a mullet and turned them
upside down when I store them.
If I just need to make some light touch up, what is the smallest size they
will sell (if I have to add colorant)?
Depends on the paint type, the temperature in garage, quality of seal, etc
etc. Latex will not tolerate freezing, and turns to a cheesy mess. My
exterior latex paints last about 5-7 years, but garage does not get near
freezing here. Towards the end of the paint's life it may get sour smelling,
but still sets properly. When I have less than 1/2 gallon unused, I pour
into quart or pint glass jars w/ paper or rubber gaskets, so that there is
almost no air. Be sure to clean threads well - paint is a wonderful
adhesive...The newer plastic paint cans will also preserve paint, as there
is no rust - a real prob. for acrylics.
Nomally they will mix a quart as a minimum, but some lines of paint are now
selling premixed sample bags that hold just a thimbleful of custom color.
<<I close the lid tight, and tapped with a mullet >> No wonder you have
probs - try a mallet.
That's your problem you tapped with a mullet. Too soft, should have
used a mallet.
Seriously, primer seems to harden slower than regular paint. I've had
paint 3/4 of a gallon last for 5 or 6 years and only 1 year with a
quart remaining in the 1 gallon can. Part of that is air space but
part is just the changes in paint formulation. You can usually buy 1
quart, but it will cost nearly 1/2 of a gallon. Turning the can
upside down probably did nothing. Adding a 1/8 -1/4 inch layer of
water on the surface of the paint or breathing CO2 into the can before
putting the lid on can help sometimes.
Store at any temperature you're comfortable at. Your garage may not offer
those conditions, especially in winter. And, there's a cheap little tool
made for opening paint cans - it hooks under the rim and opens the lid
without deforming it, as a screwdriver might. Some paint/hardware stores
will give you one for free if you ask. When closing, put a piece of 2x4 on
top and tap on THAT with a mullet, squid, smallmouth bass, or a hammer. The
hammer works fastest, but the first three are quieter.
I once asked my Benjamin Moore dealer that very same question. He said that
it would last a long time at room temperature with no air in the can. As I
was carrying several cans of paint out the door he made a point of telling
me to always keep the cans right side up. I assumed it was to avoid
I don't know what the reasoning is for storing cans of paint upside down.
The reason comes from the same school of thought which says that an unopened
container of cottage cheese will last longer if placed upside down in the
refrigerator. This idea, in turn, is perpetuated by the same people who
think you should hold your breath when you pass by a cemetery.
Storing paint upside down has some pretty credible adherents, including lots
of self help sites, university extensions, and painters. It also works for
me. Turns out paint is a much better seal, when in contact with the lid,
than an ill-fitting metal-to-metal can lid exposed to the air.. Just check
on google under phrase :
paint lasts longer "upside down"
I've stored paint "upside down" and found when I opened it that
the paint was suspended from the bottom of the can by a thin
layer of dried paint. If it's rightside up, you can remove the
extra layer and get to good paint. Stored upside down, when the
dried layer breaks, you've got paint with broken dried paint
I think paint lasts longer than the container - can gets rusty and
crumbles into the paint when opened. I have transferred paint to jars,
but that runs rish of it breaking. Have heard DIY tips to lay plastic
wrap over the surface of the paint before closing the can to prevent
drying of surface.
With a microscopic gap in the rim seal there is air exchange with internal
expansion and contraction due to temperature changes. This will permit
continued oxidation of an oil based paint forming that familiar skin on the
top of the contents. In an upside-down position, the viscous paint
prohibits the expulsion of air, stopping the air exchange.
Latex paints don't oxidize to set up. There would seem to be little
advantage to inverted storage. My experience is that they store better
unless the can starts to rust because of the water
I have used both latex and oil that was more
than 20 years old with no problem. I had several
cans of latex go bad when it got too cold when
we went about a week without power in a winter
storm a few years ago. I have also had both oil
and latex go bad in a few cases when it sat for
a year or so in a can that was way less than half
Bob <valen (at) trust-me (dot) com>
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