An oak cape rack flatpack can be made at a workbench (Steel framed bench or better) in the workshop of a player-owned house. Like when making the normal Oak cape rack, this requires 54 Construction, uses 4 oak planks and gives 240 experience. The flatpack can then be used on a cape rack hotspot in a Costume room, either in building mode or not. This requires no Construction level and gives no experience.
The cost of making and selling an oak cape rack flatpack from scratch gives a profit of: -1,867
After completing the hard Fremennik achievements, they can also be traded to Advisor Ghrim in exchange for 112 coins being added to your kingdom's coffers in Miscellania. See Flatpack: Miscellania reselling for details.
See Cape rack for a list of capes that can be stored.