The Ice Mages of a world I'm crafting can create constructs made from ice. Now, a master Ice Mage might be able to do fun things with his construct like project them in showers of ice shards, but learning to do that takes time, effort, and skill. It's unlikely a small village would have someone who can do that. On the flip side, just learning to create a construct made of ice is very easy - anyone can pick it up in a few months of minimal training, and thus everyone in a small village could feasibly be taught it. Here are the rules of the constructs:
Water cannot be created by ice magic. When creating the construct from water, you can shape it into whatever shape you want, but the water must come from somewhere. Typically ice mages will have a canteen of water (or several) on them at all times.
The ice weapon will not melt in the slightest until it is exposed to temperatures exceeding 212 degrees Farenheit (100 degrees Celsius). This is because of magic. If you create an edge from the ice, you will not need to worry about it being blunted by melting under most normal circumstances.
Exotic types of ice (basically, Ice-2 and above) are not allowed. These are typically created using pressure and thus are outside the range of the Ice Mage's ability. Ice-1 is the only type of ice allowed. (Though you are allowed to assume 100% purity of water.)
You must be in physical contact with the water to turn it into ice. You can also add more water onto a broken ice weapon to repair it / reforge it / add to it, but you cannot melt the ice at will and reform it. If the Ice Mage withdraws the magic, it functions like normal ice.
Assume that water is plentiful, but not unlimited. Also, obviously, carrying too much water would be a problem as that would weigh the Ice Mage down.
Now, the Ice Mages of this world have a problem - they're constantly attacked by the barbarian tribes. And, the barbarian tribes being true and proper barbarians, they go into battle with no armor on, and using crude stone weapons. Now, the Ice Mages may be more advanced in terms of intelligence, but they don't really have weapons either, and the best armor they have is cloth armor. They do have their Ice Mage magic, though. So the question is, given these rules for constructing ice weapons, what's the best way to establish an army to fight against armorless barbarians wielding stone weapons?
If you try traditional weapons (i.e. swords), you run into weight distribution issues. If you try massed lances, then you run into structural issues (as lances can run on the long side). And should you opt to just create giant spike walls of ice, that requires a gargantuan amount of water, which the barbarians could just run around. Thoughts?