Camping hacks - A discussion

[Galakanokis]

Best camping hack I have learned? Rent a damn RV.

[ken0042]

From what I can see, the ice packs you buy still have a melting point around 0. So at the point where it is half frozen, the ice pack is at 0 degrees. In theory my salt water pack at half frozen should be at -15 still.

[Canadianman]

Originally Posted by ken0042

A hack that I thought I read here but now I cannot find it- water bottles filled with salt water for ice. I grabbed a 4L bottle and filled it with salt water. I made the mixture as saturated as possible and froze it in the deep freeze. This past weekend I used it in my food cooler and packed as much food frozen as possible. Sunday morning I had to put the back pack in the sun to be able to thaw it enough to cook.

I guess the science of it is with the melting point being -15 or so instead of 0 degrees; even when the jug is partly thawed it sits at that temperature instead of zero. 48 hours later we still had everything frozen. Now it wasn't that warm this weekend, but this could end up being a bit of a game changer.

I use water bottles refilled with water for freezer packs. I don't think using salt water would offer any advantage. The salt water won't have a significantly different heat capacity over unsalted water, so it won't stay cold longer.



I suppose if you find it to be an advantage to have it be liquid instead of solid, then there might be a reason to use salt water, since that will thaw at a lower temperature than unsalted water.

[bizaro86]

Originally Posted by Canadianman

I use water bottles refilled with water for freezer packs. I don't think using salt water would offer any advantage. The salt water won't have a significantly different heat capacity over unsalted water, so it won't stay cold longer.



I suppose if you find it to be an advantage to have it be liquid instead of solid, then there might be a reason to use salt water, since that will thaw at a lower temperature than unsalted water.

If he gets the salt concentration to the Eutectic Point the melting point could be as low as -21 degrees C. Salt water actually has a lower heat capacity than fresh water, so you're right it won't absorb more heat. It will stay at a much colder temperature initially though, because of the lower melting point. Although as the highest concentration part melts the melting point of the remaining solid actually increases.

The phase behaviour of salt water is quite interesting - the ice will form as "pure ice" and then the remaining salt water actually increases in concentration over time.

See: https://www.tf.uni-kiel.de/matwis/am...tr/i6_2_2.html

[GGG]

With salt water I’m going to go with thaws faster but keeps your cooler colder. With regular ice your melting point is 0 C so heat exchange occurs between air in the cooler and the ice between 0C and Say 5C air temp. With a -17 melting point you now have a say -17C source and the 5C air temp so the rate of heat transfer between the ice and the air will be higher. This means the equilibrium point between heat loss to the environment and heat absorption from the ice will be lower.

[DoubleF]

Maybe using salt water bottles to pre-chill a cooler before replacing them with ice water bottles seems to make more sense to me than replacing the frozen water bottles with salt water bottles. Water bottles you can still drink and use. Salt water, not so much.

[Hot_Flatus]

Originally Posted by Derek Sutton

Ultimate camping hack, backyard fireplace. That way you can stay home.

I'm so anti camping right now, no desire to ever go again. At home we have full sized, fully functioning bathrooms, big screen tvs, two full sized fridges and deep freeze, Air Conditioning, Endy king sized mattress, Power. Camping you have dirt, stink, food in a cooler (SHUT THE COOLER!!!) sleeping on an air mattress, out houses, dirty kids.

Conclusion: Campers spend a lot of money to go live like a homeless person for a week end.

Then why comment on something you are not even into? There are plenty of positives that most people who enjoy camping savor like outdoor time with your family that isn't interrupted with TV, internet and other tech.

Allowing your kids to be outside, doing their own thing for a couple of days is incredibly valuable. To each their own, but kids (and parents) today don't get enough time away from tech and a scheduled lifestyle. Camping is a pretty easy way to be sure they are exposed to letting some of that stuff go for a few days and is hardly a slog like you suggest for anyone who has half decent equipment and some ability to plan and choose locations that fit with what they are hoping to do like biking, hiking, fishing, lazing around etc.

[Flames0910]

Campers spend a lot of money to go live like a homeless person for a week end.

Maybe. Some camp setups are pretty lux though. Think $100k camping van with $30k in custom modifications and yeti cooler, patagonia down jackets, etc... many of the homeless would be grateful to just have a tent that doesn't leak.

But going without these things also keeps us grounded. Two days without air conditioning or the deep freeze is not the end of the world and if you think it is, then perhaps you need to think a little about the privilege in your life. There are more important things in this life than air conditioning and king-sized mattresses. And time spent in nature is scientifically proven to be good for people's mental health.

[Burninator]

Camping hacks? I thought Bear Grylls was a hack. Les Stroud is the man.

[PepsiFree]

Originally Posted by DoubleF

Maybe using salt water bottles to pre-chill a cooler before replacing them with ice water bottles seems to make more sense to me than replacing the frozen water bottles with salt water bottles. Water bottles you can still drink and use. Salt water, not so much.

I’ve been trying to wrap my head around why salt water bottles would make much of a difference.

They can get colder without freezing, but whether or not the water inside freezes should make no difference to someone considering it’s being held within the bottle anyway (have a bath of salted water in your colour would make sense, because they the below freezing water is surrounding your food/drinks completely instead of the air gaps left by ice and bottles).

I’ve heard of salt water making things colder faster, but not colder for longer, since wouldn’t salt water lose heat (melt/get warmer) at a faster rate than regular water?

[edslunch]

Originally Posted by Hot_Flatus

Then why comment on something you are not even into? There are plenty of positives that most people who enjoy camping savor like outdoor time with your family that isn't interrupted with TV, internet and other tech.

Allowing your kids to be outside, doing their own thing for a couple of days is incredibly valuable. To each their own, but kids (and parents) today don't get enough time away from tech and a scheduled lifestyle. Camping is a pretty easy way to be sure they are exposed to letting some of that stuff go for a few days and is hardly a slog like you suggest for anyone who has half decent equipment and some ability to plan and choose locations that fit with what they are hoping to do like biking, hiking, fishing, lazing around etc.

The biggest plus of camping is that you are away from everything else that needs to be done or stresses you out and there's not a single thing you can do about it. Bonus points if you're out of cell coverage.

[edslunch]

This past weekend i used purchased freezer packs and some freezer packs left over from when we have a food delivery service for a while. They stayed pretty much frozen for the whole weekend. I'm never going back to water, salted or not.

Find a friend who gets Good Food or similar deliveries and they will have an endless supply of freezer packs, and a ship-ton of small plastic jars that are great for screws, nails, and other small stuff. Really good boxes too. We finally gave up on the service mostly because of the left-over packaging.

[DoubleF]

Originally Posted by PepsiFree

I’ve been trying to wrap my head around why salt water bottles would make much of a difference.

They can get colder without freezing, but whether or not the water inside freezes should make no difference to someone considering it’s being held within the bottle anyway (have a bath of salted water in your colour would make sense, because they the below freezing water is surrounding your food/drinks completely instead of the air gaps left by ice and bottles).

I’ve heard of salt water making things colder faster, but not colder for longer, since wouldn’t salt water lose heat (melt/get warmer) at a faster rate than regular water?

That's my understanding too that salt water makes things colder faster.

the only way that maybe I could see it working is maybe if it helps to keep a frozen object solid for longer?

[ken0042]

Originally Posted by DoubleF

the only way that maybe I could see it working is maybe if it helps to keep a frozen object solid for longer?

Yes, that is exactly the point, it keeps things frozen longer.

Ok, let's see if I can share my understanding of the science. Grabbed some numbers from here:
https://weather.cod.edu/sirvatka/watertype.html

It takes 1 calorie of energy to increase the temperature of 1 gram of water by one degree. That is the same of any state of water; solid or liquid.

It takes 80 calories of energy to melt water from solid to liquid. That happens with tap water at 0 degrees, and with the salt water at -18 degrees.
Bringing a 4 litre bottle of tap water up from -18 to -1 takes 68,000 calories. And at -1 it isn't doing much to keep anything frozen, just "cold."
Bringing that 4 litre bottle of salt water up from -18 to -15 takes 332,000 calories. So almost 5 times the amount of external heat applied to the cooler. (Keeping in mind that in physics there is no such thing as "cold"- just adding or removing heat.)

That being said, bringing either bottle from -18 to +2 degrees will take the exact same amount of energy eventually. (400,000 calories.) However the peak absorbtion of that energy will be at a lower temperature with the salt water. Meaning that over a long weekend the cooler gets 150,000 calories of energy applied to it, the salt ice will still be around -16 but the tap water ice will be at 0. And assuming that was 50,000 calories per day, part way through day 2 the tap water will be at 0.

At the end of the day, I can confirm that I was thawing bacon before I could cook it on the final day, and at the end of the trip I returned the extra burger patties to my freezer while still completely frozen. I also ran into an issue of my coffee cream being partially frozen the first morning.

[PepsiFree]

What was your salt/water ratio?

If you say it works as it does, then it’s worth trying. I have a trip coming up where restocking ice is difficult, but I need to keep stuff frozen on day five.

Do you think if I bought a bag of ice, poured it into a ziploc, and added salt, that I would be able to keep the mix at a lower temp for longer?

[Fuzz]

Block ice is going to last a lot longer than cube. If you have space, you can also wrap whatever it is you want to keep frozen in tea towels, it really helps insulate them.

[DoubleF]

Originally Posted by PepsiFree

What was your salt/water ratio?

If you say it works as it does, then it’s worth trying. I have a trip coming up where restocking ice is difficult, but I need to keep stuff frozen on day five.

Do you think if I bought a bag of ice, poured it into a ziploc, and added salt, that I would be able to keep the mix at a lower temp for longer?

What is ideal on day 3 or 4 IMO is more like figuring out a way to refreeze the frozen item (ie: Fresh saline from a freezer/dry ice/add more ice) or ensure that you've continued to maintain a frozen climate inside that portable frozen environment (ie: a separate cooler that you don't constantly introduce higher ambient temperature air by opening and closing).

Adding salted ice around a juice is a kiddie science experiment method that can be used to make slushies, so in theory it can help to refreeze something by dropping the temperature when creating saline, in exchange of making the ice melt faster. This can potentially be problematic if you're saying ice is hard to restock, but this is a potential solution if your frozen thing is thawing even with the ice around it and you still have plenty of ice.


I'd also be curious about a single cooler situation where if having the saline cooler packs or salt water bottles at the bottom and regular ice on top is more advantageous over just one or the other (saline or ice packs).

[ken0042]

Originally Posted by PepsiFree

What was your salt/water ratio?

It was not very scientific. I started to weigh it but then dumped a bunch of salt on the counter. I took a 4L vinegar jug, filled it half full of water. Added salt until it wouldn't dissolve any more, and then added a bit more salt. Tested freezing the 1/2 full jug to make sure it would freeze. (I didn't know the freezing point.) Then took the jug out and repeated the same process for the top half.

My rough guess would be about 150 grams of salt in 2 L of water.

[DoubleF]

Originally Posted by ken0042

It was not very scientific. I started to weigh it but then dumped a bunch of salt on the counter. I took a 4L vinegar jug, filled it half full of water. Added salt until it wouldn't dissolve any more, and then added a bit more salt. Tested freezing the 1/2 full jug to make sure it would freeze. (I didn't know the freezing point.) Then took the jug out and repeated the same process for the top half.

My rough guess would be about 150 grams of salt in 2 L of water.

Are you sure you saturated the mix? (kept going until it wouldn't dissolve more)

https://en.wikipedia.org/wiki/Saline...20(%25%20w%2Fw).

According to this, to saturate, room temp water can dissolve around 357g of salt per litre. Are you sure you got it until you couldn't dissolve any more? I just want to clarify the almost a 4x difference in salt according to the link above based on my napkin math.

I mean, salt is pretty cheap, so to saturate a 4L bottle, I think it'd only cost like 3-4 bucks for a big bag of the cheap ionized salt that is required.

This salt water discussion is making me feel like making slushies with the kids this weekend.

[PepsiFree]

Originally Posted by ken0042

It was not very scientific. I started to weigh it but then dumped a bunch of salt on the counter. I took a 4L vinegar jug, filled it half full of water. Added salt until it wouldn't dissolve any more, and then added a bit more salt. Tested freezing the 1/2 full jug to make sure it would freeze. (I didn't know the freezing point.) Then took the jug out and repeated the same process for the top half.

My rough guess would be about 150 grams of salt in 2 L of water.

Thanks, I’ll give it a shot next time and see how it goes.

Can’t be worse than the bucket of water and melted ice cream I ended up with last time.