PVA (Poly Vinyl Alcohol, not be confused with Poly Vinyl Acetate wood glue) mould release agent can be wiped, sponged or sprayed on to a wide range of pattern and mould surfaces to provide a very compatible and reliable release barrier for polyester, vinyl ester and epoxy composites.
PVA is often the first-choice release agent whenever there is increased risk of a mould sticking to a pattern or a part sticking to a mould such as when using patterns or moulds for the first few releases or when using potentially incompatible resin systems for the mould and the part (using polyester moulds to make epoxy parts for example.
Further Informations
Application Instructions
If applied properly PVA is very unlikely to fail as a release agent although whether applied by rag or sprayed onto a mould surface it will always leave a slight texture to the finished part which will need to be polished away. For this reason, PVA is often only used for the first few releases or when release problems are more likely. A mould that has done a few releases and is made out of a suitable material for the parts you will be making can then be changed over to mould release wax which can be polished to leave a mirror finish on released parts (which PVA cannot).
First, ensure the mould surface is suitably sealed (porous surfaces such as wood or plaster must be sealed before they can be used as a pattern or mould), clean and free from any contaminants.
Using a clean lint-free cloth apply a reasonable amount of PVA Mould Release Agent to an area of the rag. The cloth should be well wetted by the PVA in this area.
Wipe the rag over the surface of the mould in a smooth deliberate motion. The PVA has a dark blue die to help you to see where you have been. Ensure you coat the whole surface of the mould with a thin blue film, paying particularly attention to tight corners.
PVA is only ever applied in a single coat. Do not attempt to apply a second coat as this will simply remove the first coat as you try to apply the second coat and result in a more uneven surface.
Allow the PVA to dry fully (around 15mins) before you begin laminating.
When re-using a mould you should remove any traces of the PVA using water and clean thoroughly before re-applying PVA.Release of a mould can be assisted using water which will dissolve the PVA and help the mould or part to be released.
PVA is a traditional mould release agent (not the same as PVA glue!) and can be wiped on or sprayed onto a wide range of pattern and mould surfaces to provide a very compatible and reliable release barrier for polyester, vinyl ester and epoxy composites. PVA does, however, leave visible 'swirls' in mouldings and needs to be cleaned off and re-applied every time and so it is usually only used in situations where a mould release wax or chemical release agent would be unsuitable.
