Factors for Gloss Control of 2-Part Semi-Gloss paints.
Two-part epoxy and urethane mil-spec finishes with
semi-gloss levels of gloss are especially tricky to get correct and consistent gloss
readings from because the gloss range for this class of paint is relatively
wide, 15 to 45 degrees of gloss for urethanes like Mil-PRF-85285, and 15 to 30
degrees of gloss for epoxies like Mil-PRF-22750. Any slight variation of key
variables can change the gloss dramatically.
Here are two of the most important variables to control to get
consistent and correct gloss readings:
Homogeneous Part A.
Shake Base Thoroughly.Shake base for at least 5 minutes on a paint shaker
A paint shaker should be used for
preparing the Part A of the paint for mixing and use. Some of these 2-Part paints are heavily
pigmented and the pigment and the flattening paste tend to soft settle. By agitating the Part A’s for at least 5
minutes all soft settling and large paint particles will go back into solution
and assure a smoother paint job and a homogeneous mix resulting in consistent
paint properties including gloss. The
flattening paste must be consistently dispersed throughout the gallon, otherwise
you can get high gloss from the top of the gallon and then low gloss from the
bottom.
Check bottom of
Part A can with stir stick for settling.
After shaking for at least 5
minutes and
before mixing the two parts together check the bottom of the Part A container
with your stir stick to make sure there is no sediment on the bottom or in the
corners of the can. If you find sediment
this means that the can must be shaken or stirred for a longer period of time.
Mix Ratio. Very Important.
Check for the proper
mix ratios (See the Product Information Sheet & the Product Label)
Mix ratios are always stated as
parts per volume. So, for example, a 3
to 1 mix ratio means 3 parts of Part A to 1 part of Part B by volume and the
measurements must be accurate. Most Part
B’s of 2-part paints are full gloss materials so that even a slight mistake in
the mix ratio will quickly change the gloss reading of your final paint
job.
For mixing less than full
containers a mixing cup with gradations and/or a mixing stick come in handy to
get the ratios correct and accurate.
Accuracy in measuring is important and will insure that the paint dries
properly, and has the stated gloss, and will insure that the coating develops
full performance properties.
To view AeroCoat's complete line of epoxy and urethane mil-spec topcoats click on AeroCoat's Stocked Products List.
Dick Creek
AeroCoat Source, LLC
609.636.5858
www.aerocoat.com
