Help creating a Yosemite bootable drive

Hi guys as yosemite is no longer on the apple store would I be able to download a .dmg file of yosemite from the net and create a bootable usb drive that way? [► source]

Back in the day when we bought OS X on discs, as long as you kept that disc, you always had a bootable installer just in case. Modern, downloadable versions of OS X create arecovery partition on your drive, but it's always a smart idea to make your own bootable installer drive too.

I recommend making one for Yosemite, on an external hard drive or USB thumb drive, for many of the same reasons I recommend making a bootable Mavericks installer drive: If you want to install Yosemite on multiple Macs, using a bootable installer drive can be more convenient than downloading or copying the entire installer to each computer. If you want to erase the drive on a Mac before installing Yosemite, or start over at any time, you can use a dedicated installer drive to boot that Mac, erase its drive, and then install the OS clean and restore whatever data you need from a backup. And if your Mac is experiencing problems, a bootable installer drive makes a handy emergency disk.

Macworld also has bootable-install-drive instructions for Mavericks (OS X 10.9), Mountain Lion (OS X 10.8), and Lion (OS X 10.7).