This is very heavy weight leather, probably about 8 oz (just under a quarter inch thick). I cut two squares that would cover the pistol. When I had the two pieces cut, I soaked them thoroughly with isopropyl alcohol.

(LESSON LEARNED: If I were to do it again, I would use water. The alcohol REALLY dried the leather out, which forced me to put a lot of Neatsfoot oil on it at the end)

When the leather was soaked, I put the gun in a plastic bag, and sandwiched it in between the two pieces. I then put the whole package into a vacuum bag and removed the air. This caused the leather to form right around the pistol. Then I used a deer antler to bring out the detail around the edges. With the bag sealed I taped the bag around a coffee can. This provided the form/curvature so the holster fit on my hip.

When everything was secure, I cut the bag open and this allowed the leather to dry, which allowed the forming to become set.