Hot melt adheshive sheet for carpet backing

You can use 6" wide carpet tape, and using a 6"wide seaming iron, you can melt the tape from the backside. It might be easier if you try it out on a sample piece before you go and risk a $2000 or $3000 rug hand-tufted piece of artwork. I've been doing custom inlays for 20 years, cutting all the pieces to fit, then flipping over the main body, and adding all the pieces from the back. Then I'll lay a length of carpet tape over the added piece, and heat it up by putting the seaming iron on the back. Be sure to get it good and hot, to allow for perfect adhesion.

Waterman

Good advice below, also try Morton Adheasives, out of Rockford Il. If memory serves me they could what you need. They have a thermomelt vinyl weave for tile parque that may also work.