Polyvinyl Alcohol (PVA, sometimes referred to as PVOH) is a water soluble polymer used widely as universal millinery stiffener. This should not be confused with Polyvinyl Acetate, also known as PVA ( a popular wood glue) which is insoluble in water. http://en.wikipedia.org/wiki/Polyvinyl_alcoholFrom 100g of Polyvinyl Alcohol powder you can make 1.5l of stiffener solution (non poison!) which
can be kept in glass container with an air-tight lid for months.
Ideal stiffener for making silk, leather, fabric and felt flowers. It's water resistant.
Using PVA in hat making, treat it like your usual millinery stiffener. You paint one coat on, let dry to just damp and then block as you normally would. One of the advantages is that it doesn’t darken the straw. Whilst on the block, use a sponge dipped in PVA and squeezed out to apply the second coat, if required. Apply enough that it is not drenched, just damp and then let dry. The block must be covered with a good waterproof cover like glad wrap etc.
When you purchase this PVA powder you will have clear instruction how to apply the stiffener to different type of fabric, including silk, cotton, leather and felt.