Didn't want to hijack a thread but the topic came up a few days ago. I haven't done this in a while but when I used to decorate merch for metal bands we played with this. Basically two ways though I'm sure there are others. The easier way involves the useful but oft forgot technique of puff underbasing. I take a HD clear and add app 10% puff additive. This will be the foil adhesive. Surrounding colors may be waterbase or plastisol with foil resist (I'm not big on the foil resist properties but that's another thread) The image to be foiled is printed and flashed very quickly so that the puff adhesive is dry to the touch but not yet "blown". Rather than run through the oven the garment is taken to a heat transfer machine and finished off there. You'll need to play with time and temp to get the results you're looking for but simply place the foil on top of the garment and press away.
Now, the transfer machine will usually cure the other printed, non foiled areas but make sure you washtest. A pass through the dryer is one sure fix but be prepared for the foil to tarnish a bit. I find this treatment works best as an accent. Distressed patterns as well as clean textures and patterns are well suited for this. Thin fonts as well.
The raised foil areas will be slight rounded. For higher, cleaner "metal" looks there is another method that requires a bit more skill and practice
More on that later.tp
