Large Ice Mold (taming the beast)

[jeffulot42]

Hello all!

It has been some time since I've posted, but I have enjoyed several of the threads I've been following...

Anyway, I have a situation with ice, and I'm a comp-sci graduate from way back, not a physics person (wish I was), so I'm looking for help from someone more knowledgeable about ice and its behavior...

What we've got is an ice mold... When full it contains about a gallon of water with various contours...

When we freeze it, it bulges in the middle and causes undesired results to the "bottom" of the mold. I would not care if the open end (the top) was uneven, it's just that the bottom pushes out at the middle, and that's part of a design.

We've considered reinforcing the middle of the mold at the area is having its way with, but if there was another way to handle it it would be great...

I'm doing tests to see if I filled the mold only 1/3 of the way and freeze that first, then go back and add the rest and finish freezing that, would that prevent the push in that direction.

I'm also trying it with distilled vs. tap...

Any input is welcomed...

Thanks in advance.

S. Jeff

 

[sophiecentaur]

You could try stirring it to make sure the temperature is uniform (obviously the stirring won't work once it's actually going solid).
Otherwise, your idea of doing a bit at a time sounds good.

 

[jeffulot42]

Thank you for responding.

I will try both those ideas for sure... Sadly, each test takes 24 hours, hehe...

Do you think the partial-filled approach would create a barrier for the dreaded "push" from the rest of the water being filled?

Also, do you think tap water and distilled will bulge in different amounts?

Thanks again.

SJ

 

[jeffulot42]

I tried the two phase approach.

One time it seemed to help, where it did not bulge out of the bottom of the mold.

Another time, even with distilled water, it did bulge a little.

I'm trying to determine if I put too much down the first pass, if that's what causes the bulge. I believe I had about two inches down, and this polypropylene container is quite thin... maybe 1mm.

I'm trying another test today with only about an inch for my starter layer. Once that freezes, I'll add the rest.

My hope is that the initial layer freezes without bulging, and creates a barrier for any bulging that direction when the rest of the water is added.

Does this make sense?

Can anyone suggest anything addition to what I'm trying?

J

 

[sophiecentaur]

Why not put a largish tapered plug of plastic - (or even a bottle of water with antifreeze in it - easy to empty and later to remove) in the centre of the mould for an initial freezing. This will produce a strong case of ice around an empty central core , which you can then fill with water. The outside should support the inside bit as it expands and the expansion will be upwards. Even better: you could bring the temperature of the water you will add to the central region to almost freezing before pouring it in.

 

[Andy Resnick]

I like the idea of partially filling the mold. Plus, is the mold made from a conductive (metal) or insulative (rubber) material?