Generally, cowhide is used in making outwear, handbags, wallets, shoes and boots. It's heavy and durable, able to withstand some abuse. But leather worn against the skin needs to be lighter, thinner and more flexible so it moves with the body and can be contoured with the curves and bumps of the human figure. Lambskin, deerskin, and elkskin have all been used for this purpose. Dying skins and texturizing them adds interest and versatility making them even more suitable to the ever-changing whims of the fashion conscious consumer and the creative minds of the fashion designer.
There is a unique process employed for measuring leather because leather is unique from any other 'cloth' put together by man.
More recently, chrome (mineral) tanning has taken the place of vegetable tanning for applications of handbag and garment leather. This process is faster and allows the leather to stretch so it can be made thinner and more pliable.
Sold by the square foot, it is measured by special machines at the tanneries. The number of square feet is usually marked on the underside of the hide and fractions of a foot are always to the nearest fourth. Pieces are measured in the square so square foot calculations are fairly accurate. If you're buying a full skin, your edges will always be irregular but your square foot calulation is taken in the square.
The thickness (or weight) of leather is measured in ounces. One ounce equals approximately 1/64" thickness. So a weight of 8 ounces means the leather is 8/64" or 1/8" thick. There will always be slight variations in the thickness of leather because hides are split when wet and are not a uniform thickness to begin with.
The thickness of the leather is important to know because if you are layering two pieces of 'fabric' together, you will need to calculate your stitch length.
Tools for Leather Fashion Construction
It should go without saying that you need to use leather needles when sewing leather. But I don't like leaving anything to chance so I'm saying it. Invest in leather needles if you're going to sew on leather. You'll end up breaking your universal needles if you don't. You can't use denim needles either. Their tips are designed to go through heavy wovens by moving through the spaces between the threads that make up the fabric. Leather needles are heavy duty needles that have very sharply honed points to literally cut through the leather. Silk needles have fine sharp points, too. No, you can't use silk needles.
Let me repeat this: Invest in leather needles. You will make your life easier and your sewn leather projects will be infinitely more enjoyable to work on.
Heavy Duty Thread
Use heavy duty all purpose thread in both the needle and the bobbin. Adjust your stitch length. The stitch needs to go through both layers of leather, come back up and still give you the stitch look you want. I use a stitch length of 4-6 depending on the thickness of the leather and how many layers I'm going through. My machine will only allow me to go through 3/8" thickness. That's 4 layers of thin, fashion grade leather or 3 layers of 1/16" bag weight skin. If you sew a lot, you have your favorite brand thread. I like Gutermann brand.
Don't forget to adjust the tension on your bobbin and your pressure foot. If you have a computerized machine, it should tell you where to set the tensions. I use a Viking-Husquvarna Lily and it suggests a pressure foot tension of 3 and a bobbin tension of between 4-6 so I set it at 5. (This is only coincidental with the stitch length I use. One has nothing to do with the other).
A teflon foot allows the leather to feed evenly over the feed teeth. Machine feet are expensive but if you plan to do a large amount of work, they're worth the money and can be used for other 'sticky' fabrics as well. You can get by with your metal foot but you will need to help the feed by pulling or pushing the leather along. This takes a bit of experience. I recommend investing in a teflon foot.
Eco-Flo Leather Cement
Eco-Flo Leather Cement is put out by Tandy. It's water soluble, very easy to work with, and inexpensive. You'll need this to keep your seams from stretching. (See Preventing Leather From Stretching below).
Thread wax will aid your needle when going through the leather cement and will make it easier to remove any gunk that may build up on the needle. Typically, thread wax is applied to the thread when hand sewing. I've found it to be a great help when sewing across leather with glue on it.
If you sew, you may already have several pairs of cutting shears (scissors). If you sew a lot, you know that you should never use your best fabric shears for cutting anything but fabric. Not paper, cardboard, wire, or chicken. Leather will dull your good fabric shears fast so you'll need to invest in another good pair just for your leather.
Rotary Hole Punch
If your project requires lacing, studs, rivets, snaps or grommets, you'll need a rotary hole punch. A punch with tube sizes 0-7 is for use on lighter weight leathers where the holes are going to be punched close to the edge. You can purchase one of these for about $10. at most craft supply stores.
(You can purchase a set of individual punches but they are more costly. The benefit of individual punches is that they allow you to punch anywhere on the leather. The rotary punch is limited to about two inches from the edge of the leather because of it's design.)
Grommets & Grommet Setter, Rivets & Rivet Setter, Eyelets, Studs
Usually decorative features on clothing, they add a lot to the look of a garment. Prices vary but it's always wiser to purchase from a reliable manufacturer, especially for the setters. Tandy puts these out, too. You can purchase them at craft supply stores, Tandy Leather shops, or online.
Eco-Flo Cova Leather Paint & Brushes
Painting on leather is one of the more exciting painting experiences for crafters and fine artists. Leather surfaces allow the brush to glide and make painting enjoyable. Most leather is somewhat absorbent however and Eco-Flo is water based so test your leather first. Be sure you have the correct water to paint ratio for the type of leather you're working on. The last thing you want is for a finished product to be ruined because your paint bled out.
Note: Be careful when purchasing your paints. Be sure they are paints and not dyes.
You cannot use Spirit Solvent dye or Cova dye for this application. They are dyes designed for natural (undyed) leather. The majority of fashion grade leather is already dyed.
Eco-Flo comes in many colors including metalics, black and white. Colors are true but may require two thin coats to cover dark dyed leathers. Using any good paint brushes designed for water based paints, work in small batches so your paint doesn't dry out. I like the Taklon brushes with the soft ergonomic grips made by Loew-Cornell.