by Ron Joseph
March, 2005
Making Different Colors of Polyurethane
Q. I am in the midst of painting a sailboat and the color selections I am seeking
I cannot find with the various marine paint companies. Can I mix two different
color marine poly urethanes together for a top coat that I am looking for? I
am looking for a ruby red or wine red, can I attain this color by mixing black
with bright red? Thank you for your advice.
A. I don't have a definitive answer for you since I don't know the formulations
of the black and red polyurethanes. It is possible that you can mix the two
colors, but you will need to do some experimentation first.
Suppose the mixing ratio of the black with the curing agent is 2:1 and the
mixing ratio for the red is also 2:1, then first mix the red and black components
to give you the desired color, then mix the new mixture in the same ratio 2:1
with the curing agent.
To insure that you have not compromised (lowered the performance of) the coating,
apply the new formulation (A) to a substrate similar to what is on your sailboat.
Do the same for the red only (B), and for the black only (C). Watch the drying
and curing time of A, B and C to confirm that they are all approximately the
same. Insure that you achieve the same hardness for all three mixtures. Immerse
the coating in water for several days and check their adhesion to the substrate,
their hardnesses, etc. If all three mixtures perform essentially the same, then
you can be reasonably
sure that (A) will work .. but there are no guarantees.
Good luck,
Best wishes,
Ron Joseph
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