Some bits of info on latex. Being accustomed to liquid latex as used to create effects in the performing arts, this information may be helpful. Liquid latex consists of around 33% latex and 66% water. To this mixture, ammonia is added around 0.3%, for cosmetic latex whereas craft and mould making can contain twice the amount of ammonia, which is generally the cause of the odour. Ammonia acts as a preservative, helps the product to remain white and to control the pH. The shelf life is approximately 12 months dependent on the amount of additives included. Like many leatherwork chemicals, like contact glue, it should be applied in a space with good ventilation or a fan to direct air to an open window/door. Latex can cause an allergic reaction to certain people, which in some cases is sudden and severe; this is going to be a risk factor for the user. The high water content means there will be shrinkage as the latex dries – around 2 % to 3%. When buying liquid latex, unscrew the cap and look for yellowing and dried latex in the neck of the bottle an indication that the stock is getting on in shelf life.