Reusable Heat Packs - Neat.

I have had several of the hand sized packs for maybe 10 years. Still work.
Keep them in the snow ski bag. Once in a while one is hard (triggered on
it's own) so just boil or microwave (I boil mine normally as easy to over
microwave) and it is good as new.
Bill

"Gary Warner" <jabadoodle DeleteThis @yahoo.com> wrote in message
news:boat5b$1c3d49$1@ID-149710.news.uni-berlin.de...
 > Ok, after a quick search on the web I find I'm probably *way* behind on
 > knowing
 > about these. but anyway....
 >
 > Was in a mall the other day and being sold at a kiosk was a reusable heat
 > pack. Permanently sealed, when you "snap" a metal disk in the pack's
liquid,
 > the liquid crystallizes and releases heat. The sales-kid (and web
reports)
 > say the
 > heat will last for 45 minutes or more. The part that's really great is
you
 > can
 > reverse the process by boiling the bags in hot water - ready to be reused.
 >
 > Seems to me this could be very handy for those cold boating days or
 > possibly even in a ditch bag.
 >
 > Anyone use these and have comments and/or creative uses?
 >
 >
 > Hmmm, maybe someone could market little *cold* ones shaped like ice
 > cubes - never know when occasion for a cocktail might arise.
 >
 > Gary
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Reusable Heat Packs - Neat. 

Gary,

I used to use one for diving in cold waters. More than likely *much*
larger than what you're referring to. And yes, they really do work
well. I don't know about creative uses, but they certainly work well
when inserted in a wetsuit. You do 'recharge' these in boiling water,
but if I remember correctly, it took at least 20 minutes of boiling to
convert all the crystals back to a liquid. This is probably more
dependent on size. I got mine probably 10 years ago so they have been
out a while.

One thing I do remember is that you do NOT want to leave these
directly against the skin for a prolonged period of time. Mine came in
a neoprene pouch. They do produce a lot of heat and some divers have
been known to get burned by attempting to dive with the bare pack.
However, when you're diving in cold water ( 40 degress +/-), with a
wetsuit instead of a drysuit, you tend to want as much heat as possible.
As a result, some divers would remove them from the neoprene pouch and
place directly against their skin. Not more than once though. :^)

-JimL




Gary Warner wrote:
 > Ok, after a quick search on the web I find I'm probably *way* behind on
 > knowing
 > about these. but anyway....
 >
 > Was in a mall the other day and being sold at a kiosk was a reusable heat
 > pack. Permanently sealed, when you "snap" a metal disk in the pack's liquid,
 > the liquid crystallizes and releases heat. The sales-kid (and web reports)
 > say the
 > heat will last for 45 minutes or more. The part that's really great is you
 > can
 > reverse the process by boiling the bags in hot water - ready to be reused.
 >
 > Seems to me this could be very handy for those cold boating days or
 > possibly even in a ditch bag.
 >
 > Anyone use these and have comments and/or creative uses?
 >
 >
 > Hmmm, maybe someone could market little *cold* ones shaped like ice
 > cubes - never know when occasion for a cocktail might arise.
 >
 > Gary
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Reusable Heat Packs - Neat. 

Don ßailey wrote:

 > Seriously, I wish someone could explain how snapping a little metal disk
 > causes the liquid to crystallize like that.

The sodium acetate contained in the bag is a "supercooled" liquid. That
is, at room temperatures it is below the temperature it would normally
change state back to a solid.

The click of that little metal disk provides just enough energy to
trigger "freezing" by raising the temperature of a molecule or two back
up to the freezing point and those first few crystals of frozen material
release their heat of fusion to a few more molecules and the process
continues until all of the contents are frozen. The heat that is
released is the heat that was put into the solid to melt it.

The melting point of sodium acetate is around 130 degrees F and that is
about the temperature you can expect the bag to reach.

Rick<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Reusable Heat Packs - Neat. 

Jim,

Diving with them is a great idea. I didnt' go at all this year...
too busy and too broke working on the boat...but maybe
next year. I can imagine those getting hot next to your skin,
escially as you dive down the the pressure increases - pushing
it into you. But with a pouch or hand-towel or something



"JimL" <lukowski_NOSPAM_.DeleteThis@carolina.rr.com> wrote in message
news:3FA92BE1.3070703@carolina.rr.com...
 > Gary,
 >
 > I used to use one for diving in cold waters. More than likely *much*
 > larger than what you're referring to. And yes, they really do work
 > well. I don't know about creative uses, but they certainly work well
 > when inserted in a wetsuit. You do 'recharge' these in boiling water,
 > but if I remember correctly, it took at least 20 minutes of boiling to
 > convert all the crystals back to a liquid. This is probably more
 > dependent on size. I got mine probably 10 years ago so they have been
 > out a while.
 >
 > One thing I do remember is that you do NOT want to leave these
 > directly against the skin for a prolonged period of time. Mine came in
 > a neoprene pouch. They do produce a lot of heat and some divers have
 > been known to get burned by attempting to dive with the bare pack.
 > However, when you're diving in cold water ( 40 degress +/-), with a
 > wetsuit instead of a drysuit, you tend to want as much heat as possible.
 > As a result, some divers would remove them from the neoprene pouch and
 > place directly against their skin. Not more than once though. :^)
 >
 > -JimL
 >
 >
 >
 >
 > Gary Warner wrote:
  > > Ok, after a quick search on the web I find I'm probably *way* behind on
  > > knowing
  > > about these. but anyway....
  > >
  > > Was in a mall the other day and being sold at a kiosk was a reusable
heat
  > > pack. Permanently sealed, when you "snap" a metal disk in the pack's
liquid,
  > > the liquid crystallizes and releases heat. The sales-kid (and web
reports)
  > > say the
  > > heat will last for 45 minutes or more. The part that's really great is
you
  > > can
  > > reverse the process by boiling the bags in hot water - ready to be
reused.
  > >
  > > Seems to me this could be very handy for those cold boating days or
  > > possibly even in a ditch bag.
  > >
  > > Anyone use these and have comments and/or creative uses?
  > >
  > >
  > > Hmmm, maybe someone could market little *cold* ones shaped like ice
  > > cubes - never know when occasion for a cocktail might arise.
  > >
  > > Gary
  > >
  > >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Reusable Heat Packs - Neat. 

Sure. You're way-way behind.
JR

Gary Warner wrote:
 >
 > Ok, after a quick search on the web I find I'm probably *way* behind on
 > knowing
 > about these. but anyway....
 >
 > Was in a mall the other day and being sold at a kiosk was a reusable heat
 > pack. Permanently sealed, when you "snap" a metal disk in the pack's liquid,
 > the liquid crystallizes and releases heat. The sales-kid (and web reports)
 > say the
 > heat will last for 45 minutes or more. The part that's really great is you
 > can
 > reverse the process by boiling the bags in hot water - ready to be reused.
 >
 > Seems to me this could be very handy for those cold boating days or
 > possibly even in a ditch bag.
 >
 > Anyone use these and have comments and/or creative uses?
 >
 > Hmmm, maybe someone could market little *cold* ones shaped like ice
 > cubes - never know when occasion for a cocktail might arise.
 >
 > Gary

--
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--------------------------------------------------------------
Home Page: <a style='text-decoration: underline;' href="http://www.seanet.com/~jasonrnorth" target="_blank">http://www.seanet.com/~jasonrnorth</a><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Reusable Heat Packs - Neat. 

Hi Gary,
I was at "The Coleman Store" a year or so ago, and noticed warmer packs
that you simply tear open and they heat up. On impulse, I bought a
dozen, and boy do they work good. One .99 pack will heat like heck for
6-7 hours. The store also has propane powered catalytic "golf cart"
heaters. This worked well for my bridge as they are designed to mount to
a cup holder. (I have reverse cycle H&AC in the cabin) Last winter, the
few cold days we had were made quite comfortable by the little unit.

I would not consider its use in an unvented cabin or near fuel system
components.

Regards,

Capt. Frank Hopkins
<a style='text-decoration: underline;' href="http://www.home.earthlink.net/~aartworks" target="_blank">http://www.home.earthlink.net/~aartworks</a>

Gary Warner wrote:

 > Ok, after a quick search on the web I find I'm probably *way* behind on
 > knowing
 > about these. but anyway....
 >
 > Was in a mall the other day and being sold at a kiosk was a reusable heat
 > pack. Permanently sealed, when you "snap" a metal disk in the pack's liquid,
 > the liquid crystallizes and releases heat. The sales-kid (and web reports)
 > say the
 > heat will last for 45 minutes or more. The part that's really great is you
 > can
 > reverse the process by boiling the bags in hot water - ready to be reused.
 >
 > Seems to me this could be very handy for those cold boating days or
 > possibly even in a ditch bag.
 >
 > Anyone use these and have comments and/or creative uses?
 >
 >
 > Hmmm, maybe someone could market little *cold* ones shaped like ice
 > cubes - never know when occasion for a cocktail might arise.
 >
 > Gary
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Reusable Heat Packs - Neat. 

 > The store also has propane powered catalytic "golf cart"
 > heaters.

This was a Coleman product? They're small enough to fit in a cupholder? This
would be good for my cockpit.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Reusable Heat Packs - Neat.