How do you transport you MIG Cylinder in your ute?

[aussiblue]

Last time I put my Argon bottle in the boot of the Fairlane where, with everything else I had there that day, it wasn't moving. I I am concerned in the flat floor of my ute tub it will roll around and damage something. I have seen plastic chock/racks somewhere meant for this purpose but haven't been able to locate any; perhaps they don't sell them anymore because of the risk that people will use them for gas bottles (acetylene) that must be kept upright.

BTW: The thread title was meant to be "How do you transport you MIG Cylinder in your ute"; I must have got my fingers tangled somewhere.