While doing some research on creating plastisol heat transfers, I came across this article written by the fine folks at union ink company. It is lengthy, but pretty much tells you everything you could ever want to know about making transfers.
“The basic process for producing heat-applied plastisol transfers is uncomplicated. You print a design with plastisol ink, but instead of printing it directly on the garment, you print the design on special paper. The paper is then passed through a conveyer dryer where the ink is heated until it has gelled just enough to be dry to the touch. It’s important not to cure the ink too much.