Rabbit skin glue (rsg) comes in a granular form. Because of its organic nature, it needs to be stored somewhere dry where it can be safely kept for many years. To use it however, it needs to be made into a liquid solution. Rsg is used in gilding, among other things as a size or surfaces to be gilded, as a constituent of gesso and of bole. It is also used in ‘gilders water’ used in the final application of leaf. Each of these areas uses rsg at a different strength. This section is used to create a ‘10-1’ solution, from which all other recipes can be obtained from.
So, to begin with, soak 1 part of rabbit skin glue granules into 5 parts of cold water and leave for at least two hours, but preferably overnight. It is easy to make too much rsg at first, as it is hard to determine how much you will use. Due to its nature, RSG will eventually break down and rot, especially in warm weather. However, RSG glue can be kept quite safely in a refrigerator, for up to 10 days. I usually use an empty film canister for smaller gilding jobs.
The following morning (or after if you can leave it up to then) you will have found that the rsg has absorbed all the water and turned into a thick gelatinous lump. Add a further 5 parts cold water to the mix, and stir. Leave for another hour or so. Now transfer the mixture into a double boiler. One can very easily be fashioned using a clean tin can or a small bowl, and a saucepan. Just ensure the can or bowl is not in contact with the bottom of the pan. I use a couple of spoons on the bottom
Slowly heat the mixture in a double boiler until all the particles are dissolved. Although the mixture should become quite hot, it is very important that it MUST NOT BOIL. Boiling the glue, will introduce air bubbles to the mix and affect its overall properties. It does not take long for it to dissolve with gentle stirring. Eventually, you will be left with alight creamy coloured mixture. Using an old pair of tights to eliminate contaminants and lumps, drain the liquid into a clean storage container. Allow to set naturally on the side.
Once set you will be left with a jelly like substance. If you lightly pull on the top, it should split easily. When it is needed to be used, just reheat in a double boiler. It melts at quite a low temperature. Store in the fridge! Or else it will go mouldy quite quickly. Which my wife has nagged me about several times... it can throw of quite a stink!