More like 6 months.
"Despite the fairly simple system (mostly because the regulations do not allow many other variations), the carbon fibre elements make the brakes a highly expensive part of a Formula One car. Both the pads and the discs are manufactures from the best carbon fibre available (long chain carbon, as in carbon fibre). In fact it can take up to 5 months to produce a single brake disk. The first stage in making a disc is to heat white polyacrylo nitrile (PAN) fibres until they turn black. This makes them pre-oxidised, and are arranged in layers similar to felt. They are then cut into shape and carbonised to obtain very pure carbon fibres. Next, they undergo two densification heat cycles at around 1000°C. These stages last hundreds of hours, during which a hydrocarbon-rich gas in injected into the oven or furnace. This helps the layers of felt-like material to fuse together and form a solid material. The finished disc is then machined to size ready to install onto the car."
I believe Racecar Engineering has had a couple of good articles.