Air-drying
Epoxy and Polyurethane coatings are normally two components systems, consisting
of a base and a hardener. The two components have to be mixed in the ration
recommended to ensure proper and complete curing of the coatings. Improper
ratio leads to problems like soft/non-dried film poor performance, etc.
The
base and hardener are to be separately mixed first to obtain a homogeneous
mixture. The hardener is to be added to the base slowly, with continuous
mixing/agitation and not the reverse. After complete addition, mixing/agitation
is to be continues to achieve a homogeneous mixture. Power agitation in
preferred over hand mixing.
Any
addition of thinner to achieve the application viscosity should be made
only after the components are thoroughly mixed and not to the base/hardener
or while mixing of the two components are in progress.
After
thorough mixing of the product, the maturation time as indicated in the
product data sheet is to be allowed before applying the product. The mixture
thickens as the time progress and at the end of the pot life period, the
mixture become highly viscous and unusable. It is the best to consume
mixed paint at least one hour before the end of the pot life.
Avoid
using excess solvent than the recommended volumes, since this leads to
lower the recommended DFT buildup, sagging, longer curing time, etc.
|