Iron Bars are - as shown on the images to the right - building-elements very similar to fences that will change their shape according on their neighbouring blocks.
They can be crafted in your Crafting Menu (default key "Q") or at Crafting Tables (that still exist in worlds created before R22 on September 16th 2015), but only after the crafting-recipe has been unlocked upon taking/crafting an Iron Bar for the first time, that can be smelted from Iron Ore in a Forge.
To craft 8 Iron Bars at a time, you'll need (as of R29 in February 2016):
- 1 Iron Bar made in a Forge from Iron Ore
- 4 Iron Rods made of Iron Bars in a Processor or found in Iron Treasure Chests or in Diamond Treasure Chests
- 1 Obsidian Rod made of Obsidian (bars) in a Processor or found in Iron Treasure Chests or Diamond Treasure Chests
- 2 Globs of Goo made from Mold in a Processor or looted/harvested from many creatures including Pigsies
Currently no further crafting-recipes will be unlocked by crafting (or taking) Iron Bars any longer, which has been the case in earlier versions of Creativerse.
If you just place one of these "bars" on the ground with no surrounding blocks nor things that the "bar" can combine with, it will only be and stay a single iron pole with 4 protruding jointlike parts.
If you place two or more of these bars next to each other, they will merge into a grating that can be of course extended upwards as well. As the "bars" will merge with neighbouring blocks on all sides they will turn into mullion and transom like the cross of a window if you place a bar into a hole, no matter if vertically or horizontally.
While fences usually prevent Pets as well as wild Creatures from climbing over the low fence, you should make sure to place three or more Iron Bars on top of each other to form a cage to fence in your Pets properly.