There are several different methods you can use to slice a block of soap into bars, depending upon the type of mold used and the variety of soap. Some soapmakers like to pour into a towerlike rectangular mass, and then use a cheesewire to slice this block into layers and bars. Others, like myself, prefer to pour the soap into a one layer thick rectangle. Once the soap is firm enough, this mass needs only to be sliced lengthwise and crosswise, brownie-style. In my opinion, this method allows the soapmaker more control and precision, as it requires less dexterity than the three-dimensional tower. I figure that the fewer cuts I have to make, the greater the odds of my winding up with fairly even bars of soap. I have more control over a knife than I do a piece of cheesewire or fishing line.
Though each batch of soap is unique, most of the recipes in this book will produce soap which will harden enough to slice within one to seven days. Once moderately firm pressure (using your fingertip) meets with resistance, your soap is ready to be sliced. For a vegetable soap made with a high percentage of coconut and palm oils, this is usually soon after the twenty-four-hour insulation period, or within a few days.
Deep inside, the soap will still be somewhat soft, but the bars will harden fully as more surfaces are exposed. Soaps or shampoo bars which incorporate a large quantity of citrus oils can take longer to harden. Also, formulas which include a high percentage of unsaturated oils can take a few extra days.
First, I slice the bars lengthwise and crosswise. Mark each side of the tray with permanent marker at the correct measure, every three inches on the ends and every 2 
inches on the sides. Then lay a ruler on top of the soap, and connect the opposite sides by cutting a slight impression along the length of the ruler using a paring knife. Once all of these lighter cuts are made, check for precision, and then use the paring knife to completely cut all the way through the soap along the lines drawn.
After the soap is cut into bars, lift the entire mass out of the tray, holding on to the waxed paper for leverage. Pull the waxed paper away from the sides of bars and flatten it against the work surface. Gently peel each bar off the paper, taking care not to press too hard — remember that the bars are not completely firm. Using the paring knife, slice about 
inch off the top of each bar to remove the thin layer of soda ash which forms on the surface of the soap mass. This is one of my favorite steps, for as this dull, matted finish is sliced away, the rich, uniform piece of soap below is finally unveiled.
The soaps are not yet finished, however. Stacking the soaps to complete their cure-time is as important as all of the other parts of the process. The bars still are slightly alkaline at this point and they must be handled carefully to avoid discoloration and rancidity. I do not stack the soaps, brick-style, as other manuals have suggested, for they ideally need complete exposure, with no contact with other bars.
Sometimes I lay the bars on wicker or rattan placemats. Plain brown paper grocery bags are wonderful for single layer drying. Do not use the printed side, as the alkaline bars will pick up the dye. Each bag will hold 20 four-ounce bars, and the dry, porous paper allows even the bottoms of the bars to breathe. Set these bags in a somewhat cool, dust-free environment on a shelf or a table. (Closets and drawers do not allow for enough circulation for maximum protection against rancidity.) Wait three to four weeks before wrapping the bars.
This book is about bar soaps, but I encourage you to make soap balls occasionally for fun — especially if you’ve got children who want to try their hand at soapmaking. After about a week of curing inside of the frame, the soap should be firm enough to shape by hand. If not, wait a few days longer. Without painstaking attention to symmetry, slice the batch into 40 bars, slice off the thin layer of soda ash, then, wearing flexible gloves, hand-form each bar into a large soapball. Cure for the remaining few weeks, as described above for bar soaps.
All-vegetable soap does not lend itself particularly well to decorative molding. Though it eventually hardens nicely, it is not rock hard within a day, as the best soaps for molding are. Tallow/vegetable combinations harden quickly and release from the mold with all of their edges and fine detail intact. An all-palm oil soap, or even a soap made with other vegetable oils, but primarily of palm and coconut oils, could be molded. But the skin-care quality of the soap would be inferior to a carefully designed blend.
