A Serious Question.... about ice, yep...ice.

[Jeepers Creepers]

Mate, i had one off them big table salt containers and just up ended it with the big hole open. (the salt thing, not mine)

I just poured it in until the colour of the water is the same as lemon cordial.

Now, after i'd done it all and wacked ém in freezer, i thought i should have used a measured amount so i could repeat it.

I did remove the bottles every 12 hours from the freezer and shake the bejesus out of ém to keep the salt mixed up etc.

Next time i will measure the amount, but i'm guessing, maybe 5 or 6 tablespoons of it in each.

[jclures]

I could be wrong as usual, but I am a believer the bigger the block the better the ice will keep. My reasoning for this is small blocks, i.e. milk bottles have a grater surface area so the ice melts quicker than a large solid block.
My block mould has around 10 litres of water, I know it is a little larger than the commercial blocks I see up here anyhow.

[Alan Loy]

So to sum up for the OP

Saline water has a lower freezing point but no additional ability to store thermal energy, as such, 2kg of non saline ice and 2kg of saline ice both at the same starting temperature (ie frozen in the same freezer for the same amount of time) should take the same amount of warm beer and time to bring the entire mix up to say 5 degrees.

If Burnsy is right I have just wasted my time adding salt to the water to make blocks.  Does everyone agree that fresh water works just as good as salt water for the esky ice?

[Bird]

Just use dry ice much easier and cleaner. We used to use it prior to the Waeco.

Would get a shovel full from BOC and make an inch or so layer on the bottom of the esky. Then a layer of newspaper and a tea towel on top then all the pre chilled food.

thats interesting, when I went to buy some Dry Ice from joint in Dande befor our Flinders trip (using techni-ice boxesw), the bloke told me not to bother as it would freeze everything solid being -75c and all
He had had plenty of people come back complaining of their steaks being titanium hard days later. He gave me a cup full and said go try it and see what you think...
Didnt bother.. used Techni-ice sheets, and they were Shit too

[Jeepers Creepers]

I tried some techni ice sheets a few years ago when we did the house boat thing up the straits.

The bloke in Gympie wouldn't or couldn't sell me dry ice 2 years ago, as he reckoned folks were burning themselves with the dry ice.

I've never been a fan of the techni ice, but it did keep $50.00 of Cold Rock Ice Cream ok until we got it in the freezer on the house boat.

Thats a good holiday too, get a house boat out of Tin Can Bay.....

We had 6 of us on a 54 foot house boat, 3 tenders off the back, the works.......
It's funny ya know, it was standing on the upper deck of the house boat on that trip when i said to Mrs. Jeepers, ya wanna sell up and move to Tin Can?

[Hefty]

Appologies if someone has already answered this. How much salt do you add?

Plus we used to freeze 2 ltr bottle but found that 2 ltr ice cream containers took longer to melt (have come home from a 5 day camp and still had ice in our tropical Ice box). We put a freezer bag in the ice cream container then the water. Every couple of days leading up to a camp we take the freezer bags out put it back in the freezer then do it all again. Before putting them in the esky we triple freezer bag so they don't leak.

LB

I researched this at the end of last year and have been using them ever since.
I think I used this site http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/meltpt.html to figure it out and went with 15% by weight to get approx -10 degrees C. I use 3L juice bottle and kitchen scales. My freezer can just handle the 20% -16 but it takes a lot longer to get a good hard block.
In my researching I came to pretty much the same conclusion as Burnsy but I still use them along with pure water ones to give me a rough idea of temp. Eg, Ice in salt bottles and pure water bottles approx -10. Water in salt bottles, ice in pure water bottles between -10 and zero (I approximate by how much salt ice is melted). Water in both, above zero degrees.
Then you just have to make sure the salt ice bottles are clearly marked so you don't try to use them for drinking water once they melt!!
I've started to avoid the salt ice on weekend trips because all it does in that space of time is refreeze stuff.

Cheers!
Jono.

[ozbogwam]

thats interesting, when I went to buy some Dry Ice from joint in Dande befor our Flinders trip (using techni-ice boxesw), the bloke told me not to bother as it would freeze everything solid being -75c and all
He had had plenty of people come back complaining of their steaks being titanium hard days later. He gave me a cup full and said go try it and see what you think...
Didnt bother.. used Techni-ice sheets, and they were **** too

Yeah you need to be careful not to use too much and make sure your food isn't in direct contact with it hence the newspaper/tea towel barrier.

We used it for a week trip in summer in hot weather and it worked really well

[Jeepers Creepers]

well, the iced salty stuff did work better than normal ice, IMHO.

I threw some party ice in with it before leaving home and for the first few days, the beers were that really nice, icey cold.

By day three, i was throwing one bag of party stuff in each day, but think it went better than normal ice.
The beer was still nice and icey cold....
But lets face, when you've dicked around to try something new, you always think it works better, its human nature.

I will do it again, but next time, i'll measure the salt amount and try for a more confirmed idea if its worth the rooting around.