Properties. Urethane is flexible and malleable, making it ideal for objects that have different shapes and forms, and it is used in liquid form. Polyurethane, on the other hand, is stiff and rigid and is ideal for firmer items, with many advantages over natural rubber.
One may also ask, is spar urethane durable? A ships spars get exposed to an unusual amount of wind, sun and moisture, so spar varnish has to be more durable than regular varnish to last for any length of time. Spar urethane, of which Minwax Helmsman is a leading brand, is spar varnish that includes urethane plastic as one of its resins.
Similarly, what is spar urethane used for?
Minwax Helmsman Spar Urethane is specially formulated as a protective clear finish for exterior or interior wood exposed to sunlight, water, or temperature changes. Contains UV blockers to reduce the suns graying and fading effects. Forms a protective barrier against rain and moisture.
Can I apply polyurethane over spar urethane?
Spars have a greater oil ratio than an interior varnish or oil base polyurethane. Coating over it with either of those would maintain that softness/flexibility as a base coat. High End spar varnishes ( I wouldnt use these indoors) tend to take much longer to dry and stay much more flexible than spar urethane.