Long-Lasting Reusable Ice Pack for Low Back?
August 4, 2015 4:04 AM Subscribe
I can't find any good ice packs anymore and this seems to be a problem for a lot of other gimpy people. Gels--freeze too cold and don't last long. Clay--not cold and don't last. Is there anything else that works?
The best therapeutic ice packs I ever used had little packets of saline suspended in a gel--the saline would freeze hard but were small enough that overall ice pack was flexible. As saline "unfroze" they'd keep the gel just at perfect temperature and the ice packs lasted a long time. Can anyone recommend either something similar to that or another technology that works?
The best therapeutic ice packs I ever used had little packets of saline suspended in a gel--the saline would freeze hard but were small enough that overall ice pack was flexible. As saline "unfroze" they'd keep the gel just at perfect temperature and the ice packs lasted a long time. Can anyone recommend either something similar to that or another technology that works?
Those recirculating ones are legit. My grandma had one for her back a few years ago and it was awesome. Cons: you have to lug a cooler around with you (but great for home use) and they're probably expensive if you can't get a doctor to write you a Rx for one.
posted by phunniemee at 6:17 AM on August 4, 2015
posted by phunniemee at 6:17 AM on August 4, 2015
Best answer: i hadn't heard of what you describe, so went looking. is this what you are looking for?
if so, this seems to be a good google search and they are available from amazon.
(i did wonder if they were no longer available because prolonged cold is not so good for you - the "usual" 3m gel packs i use carry warnings) (otoh i guess it's kind of obvious so sorry if you've already considered this).
posted by andrewcooke at 6:23 AM on August 4, 2015 [1 favorite]
if so, this seems to be a good google search and they are available from amazon.
(i did wonder if they were no longer available because prolonged cold is not so good for you - the "usual" 3m gel packs i use carry warnings) (otoh i guess it's kind of obvious so sorry if you've already considered this).
posted by andrewcooke at 6:23 AM on August 4, 2015 [1 favorite]
Sounds like andrewcooke may have found it, but, if not, in my travels I frequently am surprised by the sharp difference in consumer products in different countries (we're not completely cookie-cuttered yet!). I'd start with shopping sites from English speaking countries, but then move on to using google translate for foreign ones. Lots of stuff that's fallen out of popularity here is still being made, sold, and used elsewhere. Also lots of stuff we haven't thought of yet!
posted by Quisp Lover at 6:58 AM on August 4, 2015
posted by Quisp Lover at 6:58 AM on August 4, 2015
I don't know much about ice packs, but I did stay at a Holiday Inn last night am a physicist.
Gel and clay are equally "cold" in the sense that, if you leave them long enough in the same freezer, they will reach both read same temperature--the freezer's temperature.
What makes gel feel colder / too cold for you is that heat will flow from your body into the gel faster, that is, it has high thermal conductivity. Clay has lower thermal conductivity, so that heat flows more slowly from your body into the clay.
The other issue is how long it lasts—and I assume you mean how long the ice pack stays cold, rather than the durability of the materials. Part of that is determined by the heat capacity. A material with higher heat capacity can absorb more heat from your body for each degree that its temperature increases. So you want a material with high heat capacity to maximize the heat it absorbs before your body before it no longer feels cool.
But the other thing that determines how long it stays cold is, once again, the thermal conductivity. If heat flows quickly from your body to the pack, the pack's temperature will increase more quickly.
So you want to have high heat capacity, and the correct thermal conductivity—too fast and it'll feel too cold, too slow and it won't feel cold enough.
As troytroy suggests, I think the answer here might be to insulate the pack with a material with low thermal conductivity, like fleece. This will slow the rate of heat flow from your body so that the pack doesn't feel too cold, and will also make the cold last longer. If you insulate it all around, that will also reduce the flow of heat from the environment to the ice pack, so that will stay cold longer.
I hope this helps, and good luck with your quest!
posted by BrashTech at 7:49 AM on August 4, 2015 [3 favorites]
Gel and clay are equally "cold" in the sense that, if you leave them long enough in the same freezer, they will reach both read same temperature--the freezer's temperature.
What makes gel feel colder / too cold for you is that heat will flow from your body into the gel faster, that is, it has high thermal conductivity. Clay has lower thermal conductivity, so that heat flows more slowly from your body into the clay.
The other issue is how long it lasts—and I assume you mean how long the ice pack stays cold, rather than the durability of the materials. Part of that is determined by the heat capacity. A material with higher heat capacity can absorb more heat from your body for each degree that its temperature increases. So you want a material with high heat capacity to maximize the heat it absorbs before your body before it no longer feels cool.
But the other thing that determines how long it stays cold is, once again, the thermal conductivity. If heat flows quickly from your body to the pack, the pack's temperature will increase more quickly.
So you want to have high heat capacity, and the correct thermal conductivity—too fast and it'll feel too cold, too slow and it won't feel cold enough.
As troytroy suggests, I think the answer here might be to insulate the pack with a material with low thermal conductivity, like fleece. This will slow the rate of heat flow from your body so that the pack doesn't feel too cold, and will also make the cold last longer. If you insulate it all around, that will also reduce the flow of heat from the environment to the ice pack, so that will stay cold longer.
I hope this helps, and good luck with your quest!
posted by BrashTech at 7:49 AM on August 4, 2015 [3 favorites]
I had the same issues. Ended up using a large fairly generic CVS gel-pack, with a square piece of an old t-shirt as an insulation layer (flat or folded depending on location pack is applied to), and a piece of elastic with velcro on both ends to bind it. I'm fairly happy with it.
I searched a fair bit in the US, online and in various drug-stores. Purchased a few, this was the winner. If I recall correctly, you can buy the packs alone, or in a sorta "deluxe" box with a piece of crap itchy stupid fabric holder thing. The elastic/velcro band came with one of them though, and it is useful, basically like an ace bandage, but easier to re-use.
posted by Jack Karaoke at 9:10 AM on August 4, 2015
I searched a fair bit in the US, online and in various drug-stores. Purchased a few, this was the winner. If I recall correctly, you can buy the packs alone, or in a sorta "deluxe" box with a piece of crap itchy stupid fabric holder thing. The elastic/velcro band came with one of them though, and it is useful, basically like an ace bandage, but easier to re-use.
posted by Jack Karaoke at 9:10 AM on August 4, 2015
Horse leg wraps. I used something similar (at a physical therapist's recommendation*) many years ago. You never put a pack on skin, so it went in a pillowcase.
*A human is only supposed to ice for max 20 minutes at a time in most cases, with a minimum 20 minute rest between, so they actually shouldn't stay cold very long. 3-4 packs, rotating every 40 minutes, should be sufficient. You can use something like this oversized gel pack to get better coverage and still have some flexibility.
posted by Lyn Never at 9:32 AM on August 4, 2015
*A human is only supposed to ice for max 20 minutes at a time in most cases, with a minimum 20 minute rest between, so they actually shouldn't stay cold very long. 3-4 packs, rotating every 40 minutes, should be sufficient. You can use something like this oversized gel pack to get better coverage and still have some flexibility.
posted by Lyn Never at 9:32 AM on August 4, 2015
Response by poster: Thanks for the responses.
On the Physics front, the key advantage of the saline nugget design is that the saline goes through a phase change, which is why it offers dramatically better heat capacity than the gels.
posted by Jon44 at 4:57 PM on August 7, 2015 [1 favorite]
On the Physics front, the key advantage of the saline nugget design is that the saline goes through a phase change, which is why it offers dramatically better heat capacity than the gels.
posted by Jon44 at 4:57 PM on August 7, 2015 [1 favorite]
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posted by troytroy at 6:12 AM on August 4, 2015