Local solutions, corners

Poly(vinyl alcohol) is also frequently used. It is available in coloured solutions, and can be sprayed or brushed. One problem with poly (vinyl alcohol) is the low viscosity of the solution. This means that it drains down slopes and collects in recesses or sharp corners. It may then take a long time to dry, and will not offer protection in these local areas. The use of water/methanol solvent mixtures gives a faster evaporation of solvent after application than water alone. A slow rate of evaporation can result in a long delay before it is safe to proceed to the next step, e.g. the application of a gelcoat which must be applied to a dry surface for satisfactory cure. 

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