An easy commercial ice-lantern mold
The commercially-available Arctic Ice Lantern mold offers several advantages and one significant drawback -- a tendency to crack if the ice freezes too hard inside. The mold is extremely easy to use, produces a versatile and decorative luminary, and nests together for storage. It has a list price near $20 and is often on sale for less than $10.
I love these molds and have a lot of them. They look great even without ornamentation, and they accept a wide variety of added decorations, fit well together to build bases for other ice luminaries, and can be stacked to make ice castles. In the spring, they make great frost protectors for tender plants. Really, if they were a bit sturdier, they would be perfect.
Just be aware that these molds really do need to be watched to keep them from cracking while they freeze. If you can't be compulsive enough to do that, you will be much happier with the ice globes. (Although both the Arctic Ice Lantern and the Wintercraft Globe are local products in Minnesota and are often sold from adjacent displays, they are marketed by two different companies.)
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| An Arctic Ice Lantern decorated with stars on its faces and around its rim, and stacked on another Arctic Ice Lantern for extra height. |
How to use the Arctic Ice Lantern mold
To use the Arctic Ice Lantern, you fill it with water up to about an inch from the top, then leave it to freeze for several hours, even more than 24 hours if the temperature isn't very cold. At low temperatures, however, it may take just a few hours, and there is a risk that it will freeze all the way through and crack the mold.It takes some practice to gauge the right time to unmold the luminary. The thickness of the walls can be estimated by looking down into the mold and seeing whether they appear to be about an inch (2.54 cm) thick. They can be a little thinner or thicker, but if they are too thin, a proper upper edge won't develop, and if they are too thick the center well may freeze over so that it has to be melted to release the water from the core.
When the ice lantern has frozen enough, the mold can be turned over in a warm place and either left for a few minutes to unmold by itself or hurried along by pouring hot water over it. Here's where not filling the mold all the way to the top is useful; the ice lantern will drop down when it is ready, and the mold can be lifted off easily.
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| The Arctic Ice Lantern mold is hexagonal, with an indentation in its base that becomes the opening in the top of the luminary. Here, the mold has been turned over and left in a bathtub to unmold itself, which takes five or ten minutes. The process can be accelerated by pouring hot water over the mold. |
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| The mold has been lifted off, showing the ice lantern with the open center and the liquid water in the core. If it has frozen too hard, there may be a crust of ice across the center. I use a metal bowl with a flat bottom and fill it with hot water, then spin it over the frozen center to melt a hole into the core if it has frozen too far to simply drain the water. Save the water from the core to freeze the next ice lantern, or use it to weld the luminary to the ground or to attach its decorations. |
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| Molds for ice shot glasses and star-shaped muffins decorate this Arctic Ice Lantern. With a bit of cold water, the additional elements quickly weld in place on the luminary. Further ice decorations can be added to the six faces of the ice lantern. |
The hexagonal ice lanterns are especially well-suited to decorating.
See the separate blog post for making decorations for detail.
When making ice appliques,
it is best to fill the molds only part way, so that the surface isn't
convex. A slightly concave surface improves the adhesion. For
the large stars on the upper rim, it's fine if their mold is filled
to the top. To make the appliques stick, dip them in very cold
water before touching them or pressing them in place. The water
from the core of the mold can be saved for this purpose.
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| Stacking the Arctic Ice Lanterns brings the decorated uppermost luminary closer to eye level for people passing by on the sidewalk. The smaller stars are from a tray for ice "cubes," while the larger ones were made in a silicone muffin tray. Pink hearts decorate the lower levels of this tower. |
Science saves the ice lantern
Two problems with "bucket" style ice lanterns can be solved with some understanding of the science of water freezing.Preventing lumpy bottoms: Water expands as it freezes, so the ice forming on the walls of the mold presses inward against the core of liquid water and outward against the walls of the mold. Pressure builds up inside. If there is a tiny crack in the ice (often where there's an impurity), the water from the core will flow up and freeze into a raised area on the surface, making the top lumpy. When the ice lantern is turned over, this becomes an uneven bottom that doesn't sit nicely on a flat place. One way to keep the surface smooth is to use purer water, so there aren't weak spots. This might just allow higher pressures to build up inside, however.
Avoiding mold cracking: If the pressure isn't relieved by water escaping through the ice, the mold may crack when the ice lantern continues to expand inside it.
The solution: Relieve the pressure inside in a controlled way. During the freezing process, I take a cordless drill with a quarter-inch bit and drill a little hole into the center of the lantern. The high-pressure water inside can spray several inches up when I do this. With the pressure relieved, the water won't find its own way up and make a lumpy surface, and it won't stay inside, pushing outward to crack the mold. I still monitor the freezing process to avoid letting the walls get too thick, but -- you might say -- the pressure is off.
Visit a Flickr Album of Arctic Ice Lantern ideas.
Sadly, I found out the hard way that these lanterns do Crack and fail when they freeze too quickly. I will follow your advice to reduce the likelihood of that occurring with the replacement.
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