Work with something easy.
Does heat transfer vinyl work on leather.
Here are the basic steps.
Any siser htv can be adjusted to the method outlined in this blog post on heat sensitive items.
Applying heat transfer vinyl to leather is simple and honestly very similar to applying heat transfer material to any other surface.
Mirror image and cut.
The first step is to mirror your design in your cutting software.
Siser heat transfer vinyl can be applied to rayon polyester and poly blends modal and more heat sensitive fabrics if you use a lower temperature and a longer pressing time.
These can then be transferred onto fabrics like clothing bags and pillow covers to name a few.
Siser easy weed extra is specially made for heat pressing onto leather garments should work just fine on a leather gun bag.
Heat transfer vinyl is cut on the back side of the material so your design has to be flipped in.
Cotton and cotton blends are always safe for siser htv as.
However since it is a chemical and faux leather can be made of many things i recommend spot testing a small area with the remover to see if there will be any discoloration before moving forward and removing the htv.