Leather quality will vary considerably. Be careful of your sources. Two of the best US tanneries are Hermann Oak and Wickett & Craig. Neither of these generally sell direct to individuals, and minimum orders are usually in the 200-400 sq. ft. range (or about 300-500 holsters!). Contact Springfield Leather Company (google search for the website), a very good supplier usually having Hermann Oak vegetable-tanned cowhide in stock, and they will sell by the square foot for small orders. You will want either shoulders or sides, and you should avoid bellies. For small and lightweight handguns leather as light as 6-7 oz. can be used. For large and heavy handguns 9/10 oz. is a good choice. For most common holster work 7/8 oz. can be used with good results. Needless to say, the heavier the leather the more difficult it can be to cut, stitch, form, etc.

Leathers provided by hobby shops and many distributors is usually imported. There is no way to know what tanning processes were used, but the use of excrement and urine (animal and human) remains common in many countries. We want good vegetable-tanned leather produced with tannins from tree bark, reduced to a fine powder so that it dissolves easily in water; an expensive and time-consuming process, but the best for our purposes.

Leather is a fibrous material produced from the skins of animals. The fibers are bound together by a substance known as collagen. When veg-tanned leather is wet-formed the fibers will be stretched considerably as the leather is forced into and around the contours of the handgun. As the leather dries the stretched fibers will tend to contract and shrink. One of the challenges for the holster maker is to use these qualities to advantage. In large production facilities the degrees of stretching and shrinkage are calculated into the patterning, cutting, assembly, stitching and other operations, and holsters are formed on dummy gun under high pressure in a press. In small shops and for hobbyists the forming work is generally done by hand and with the aid of a few tools (a process known as "boning" because the tools were traditionally made of bone, antler, or ivory in varying forms and shapes), and I will concentrate my further comments on that approach.

The pattern used must allow for the handgun to be forced into the dampened leather after assembly and stitching have been completed. This means that there are practical limits to how closely the holster "pocket" can be fitted to the contours of the handgun. Too close and it will be impossible to fit the handgun into the holster. Too loose and it will be impossible for the holster to function without repeated flexing in use resulting in a sloppy fit. A simple rule of thumb (not entirely precise, but sufficient for most applications) is to use the dimensions of the handgun plus 1/2 the thickness of the handgun, then add the thickness of the leather in use (leather is gauged by thickness, referred to as weight in ounces, with each 1 oz. of leather weight equaling approx. 1/64" thickness; hence leather of 8 oz. weight is approx. 1/8" in thickness). This will vary depending on the handgun, but will usually get you into the ball park. (By the way, the first holster produced from a new pattern will seldom be perfect, and some adjustment of the pattern will usually be required, and this process may need repeating more than once before the end product meets all expectations).

After assembly and stitching the holster may be wet-formed. I recommend using water at room temperature to luke warm. A couple of drops of dishwashing soap can be added to a gallon of clean water, and this can ease the forming process a bit. I like to dip the leather into the water, allowing one second per ounce of leather weight (7-8 seconds for 7/8 oz. leather). The leather will then be quite supple and easily worked. Force the handgun (or dummy gun) into the holster pocket, carefully aligning edges all around. Basic contours of the handgun can then be formed by impressing the leather with fingers and/or a smooth rounded forming tool (polished wood, plastic, bone, antler, etc, and no steel or other metal). The piece is then ready to begin the drying process and continue forming and boning.

I like to use a small convection oven with a piece of smooth wood over the metal rack, set on the lowest setting and having the door propped open about an inch (keeping the interior temperature at about 120-130 degrees, use an oven thermometer). The wet holster goes in (no gun or dummy) for 8 to 10 minutes (use a timer). The leather will then be taking its shape and damp to the touch. The gun or dummy can be reinserted and forming can be continued, again using fingers and/or smooth rounded tool, and any needed contouring (belt loops, etc) can be started. Then the holster goes back into the oven for a second 8-10 minutes. The leather will then be moderately damp to the touch and final shape will be starting to set up. Time for close fitting and boning to final form. Then the holster goes back into the oven for a third 8-10 minutes. The leather will then be nearly dry to the touch, with little remaining moisture in the fibers. Final boning can be done at that point. Then the holster goes into the drying cabinet (constant 105-108F interior temperature) where two to four hours are required for complete drying.

What has been accomplished so far is to bring the holster to final form while also releasing the hold of the collagen to the stretched and formed leather fibers and allowing the collagen to reset everything to the desired forms. This manipulation of the collagen has been accomplished by holding the leather at a temperature in the range of 120-130F as the initial drying takes place.

The holster can then be sealed and finished. These processes usually involve applying moisture to the leather, and this can result in some shrinkage. So, after the sealants and finishes have completely set up (12 to 24 hours) you may find that the holster's fit to the handgun is tighter than desired. A good fix for that is to place your handgun into a plastic bag (shopping bag, sandwich bag, etc), then force it into the holster and leave it for several hours (or overnight), which will usually stretch the leather sufficiently for break-in use to proceed.

I recommend against drying the newly formed holster with the handgun in place. Why? As the holster dries the water is evaporating into the air, and that moisture-laden air will penetrate into every nook and cranny of the handgun's internal parts. This could result in corrosion to springs, pins, and other critical parts over time, and could only be corrected by a complete detail-stripping down to the smallest part for cleaning and removal of all moisture. Some folks think that stainless steel won't rust, which is not correct; it is more corrosion resistant than carbon steel, but not corrosion proof. Some folks think that aluminum won't oxidize, which is also incorrect. Why take unnecessary chances?

Also, drying the leather completely with the handgun in place could result in the handgun being impossible to remove without cutting the leather off, which is not quite the end result you are seeking.