I don’t think a 12 v element will get hot enough. We change out the elements on the credit card stamps to get hotter ones. These are the ones I bought but have not tried them yet. The guy that came up with the idea of the credit card press did a bunch of experiments and says they have to be at least 300 watt.
https://www.ebay.com/itm/US-Stock-2x-NEW-AC110V-300W-Mold-Heating-Element-Cartridge-Heater-Tube-Rosin-DIY/352483764452?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Heres the silicone pad
https://www.ebay.com/itm/SILICONE-SPONGE-RUBBER-1-2-THK-X-12-X-12-SHEET-HIGH-TEMP/223161425660?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649