Boiled leather is vegetable-tanned leather that has been boiled in water. This yields a leather that is very stiff and hard. In the past, boiled leather was used to make armour. While not as protective as metal armour, it is much cheaper and easier to make. Many people find boiled leather useful for making their own armour for costumes or entertainment.
Cut out the piece you want to boil with a knife. Boiled leather will shrink somewhat, so make the piece slightly larger than you actually want. Only use vegetable-tanned leather, which is tan-coloured and has no grey edge.
Soak the leather in a pot of warm water for at least 10 minutes. The longer it soaks, the more water will enter the leather, which makes it more pliable. You can soak the leather for several hours if desired. Leather that will be shaped into sharp curves requires more soaking.
Take out the leather and pour out the water from the pot, refilling it with fresh water. Boil the fresh water.
Put the leather into the pot, boiling it for between 20 seconds and a minute. This results in a tough leather, but the quick process may result in uneven material. You can heat the leather in the pot with the water temperature between 77 to 87 degrees C (170-190 degrees F) or a more controlled result.
Remove the leather from the water using a flat instrument. Tongs are suitable, but may leave marks on the leather.
Drape the leather over your form. Boiled leather takes the shape of the item on which it is formed. You may require protection for your hands depending upon the intricacy of the item you are making, especially if the leather needs stretching. Gently tie the piece in place with strips of cloth. Tying too tightly can result in marks on the leather.
Wait for the piece to dry. You can also bake it in the oven at a temperature no higher than 93.3 degrees C (200 degrees F).
You may want to wear gloves. The chemicals from tanning leather can leach into the water, and these chemicals can be toxic. Many people treat the leather with wax for additional hardness and waterproofing. There are many methods for this. Use wax that is soft, but not so hot to be liquid, and only treat leather that is completely dry.