ShopBot with a 4'x8' bed or larger and associated tooling
Cordless drill and wood screws (for hold downs)
4'x8' sheet of 3/4" melamine board (as of writing this, sold at Home Depot but not Lowes (its actually 49'x97'))
The melamine board is usually pressed chipboard with a hard and flat plastic surface, usually comes in white and sometimes black. Its the same stuff that is used to make the sort of cheap furniture that falls apart if you ever try to move it (and yes, you could use that falling apart shelf or entertainment stand to make platens!)
A platen is a hard waterproof and flat surface that is slid into or behind the object to be printed. It is usually coated with a spray on tacky repositionable adhesive. When fabric is positioned on the platen it becomes hard, immobile, and rigid. This allows the printing to have even pressure across the surface (and thus result in good ink transfer) and keeps the shirt immobile for multicolor printing.
Step 1: Make or Acquire ShopBot File
General sizes of platens:
You can stretch out platens to make them longer and add necks.
Also included are single and double sleeves and some small squares for printing cards and game pieces.
Step 2: Acquire Melamine Board and Shopbot!
As of publication 49" x 97" x 3/4" melamine board can be purchased from Home Depot, but not Lowes. Cost is approximately $38.
In my pictures I am using a 15" wide shelf, this is because I was in a hurry and there is no Home Depot locally to me. It all cuts the same.
Throw it up on the ShopBot, download my attached file and create your toolpaths and cut! Simple as that. A tip with the chip board - its sawdust is very fine and loose, using a compression bit to create a sawdust hold down doesn't work. Use extra large tabs and sand them off!
Step 3: Finish!
You can use your platens as is or mount them to holders for use in a press. Each press is different and when I make my "Make a press" instructable I will detail how to do this.
BTW, I made it at TechShop (techshop.ws)