One advantage of water hardening is that when the piece comes out of the water it is stretchy--more so than leather that has been soaked for a much longer time in cold water, as described in my earlier article. This makes it possible to form pieces. You must work quickly, since the stretchiness goes away in a minute or two.
Elbow cops are easy. Start with a roughly oval shape, about 10" by 7.5", as shown in the figure. Find two bowls, diameter about 6.5", that will nest together. When the piece comes out of the hot water, put it into one of the bowls, forcing it down with your fingers to stretch the leather into the bowl, then put in the other bowl, so that the leather is being stretched between the two.
Finally, take out the inside bowl and make sure that the leather is fitting into the other with no folds, crinkles, etc.--if necessary smooth those out with your fingers. Let the leather dry. Sew or rivet on straps and you have an elbow cop. For a knee cop, do the same thing, making the piece about 14" x 7.5" and using about 7.5" diameter bowls. Details will vary according to the size of your elbow and knee and how thick your padding is going to be.
A bazuband--the Islamic forearm and elbow piece described in the previous article and shown here--is a more complicated shape. There are four ways to try to make it.
1. Use your arm, wrapped in a towel, as the mold. This will probably work better with two people, giving you three hands to stretch leather. I have not yet tried doing the initial stretching that way, although I usually put the piece over my arm for the final adjustments.
2. A positive form. Get something roughly the shape of the inside of the bazuband. A steel bazuband is ideal if you happen to have one lying around, but lots of other things will do. For a less precisely designed form, but one somewhat easier to obtain, use a wine bottle with relatively steep shoulders.
With a positive form, you take the leather out of the hot water and stretch it over the form. I find that it helps to tie the wrist end of the leather around the form with strips of cloth, then do the stretching at the elbow end, which is where it is most needed. then tie that down to the form with strips of cloth. This is like making an elbow cop with only one bowl, by stretching the leather over the bowl--but harder. You may find it useful to do some preliminary stretching over a rounded corner of the kitchen table, or something similar.
3. A negative form. Get something that is roughly the shape of the outside of the bazuband and stretch the leather into it--like forming your elbow cop in the inside of a bowl.
4. Nested forms. This is the best way--once you have the forms. I've done it using a pair of steel bazubands. They don't have to be steel--once you have made a cuirboulli bazuband you are happy with, you can use it as your negative form for the next one, nested onto whatever form you used to make it.
Alternatively, you could make both positive and negative forms out of wood--by the next version of this article, I may have finished that project, using lengths of 2x4 sandwiched together and pegged. In theory, you end up with forms that can be made narrower, for thin people's arms, by removing the central piece, or wider, for big people's legs, by adding another piece.