UV is the enemy of both hatches and interior fabrics. Acrylic can resist UV for 15 years or more, but polycarbonate generally begins to haze and even craze within 5-10 years. Most hatches are tinted to keep heat and UV out of the boat, but the UV streaming through a clear hatch can fade fabrics and damage plastics.
Historically, tinted films could only be applied to the inside of windows. Improvements in adhesives and films made exterior application practical, which makes them more efficient in rejecting heat and UV. It also allows them to protect surface of the glazing.
Historically, tinted films could only be applied to glass, never plastics. The plastic glazing outgases for many years, and the gas forms bubbles, no matter how carefully applied.
POLYESTER VS. POLYURETHANE
Soft vinyl windows will outgas for years. The protective surface coating of these vinyl windows is polyurethane, which allows gasses to pass out into the air. Tinted films, mirror coatings in particular, are not as permeable as polyurethane, so they will trap these gasses, much the way a Mylar balloon can hold helium for long periods.
What about thermal expansion? Tinted films will expand more than acrylic hatches or in polyurethane in soft vinyl windows. However, since tinted film works fine with glass, which has less thermal expansion than both acrylic or polyurethane, tinting should work fine with acrylic.
WHAT WE TESTED
We tested Vvivid Smoke Black Headlight Film and BDF EX 15 Exterior Mirror film. We can’t comprehend why anyone would want to tint their headlights, but what mattered was that the Vvivid film is clearly rated for plastics. The BDF film made no specific claims. Both are exterior films.
HOW WE TESTED
We covered a polycarbonate hatch and a scrap of 1/8-inch polycarbonate (both more than 10 years old) with window films and left them exposed to the sun for a year. Why polycarbonate instead of acrylic? Acrylic hatches do well in the sun and extra protection is less critical. Polycarbonate, however, succumbs to UV much more quickly.
OBSERVATIONS
Long-term reliability starts with careful installation. You can’t get the windows clean enough, and it’s really hard to keep them clean while you apply the film. The smallest spec of grit will make a bubble. Wash the boat first, and avoid windy days. You’re probably better off working at the dock than in a dusty boat yard. Cutting to shape is best done on a cutting board, to avoid cutting the glazing, seal, or frame. On glass, the instructions typically call for installing an oversized piece and then trimming against the glass with razor, but with plastic, that won’t work.
Although cutting to fit is easy for most boat hatches, larger windows will take time and care. Cut the film with a 1/16- to 1/8-inch margin to allow for stretch, and accept that there will be a small gaps around the edges that won’t be tinted. Cutting too big will result the film wrinkling or buckling.
Use lots of soap solution when fitting into place. You can’t use too much. On the glazing side, the solution floats the adhesive apart from the glazing, allowing you to reposition the film and work the bubbles out (don’t worry about trapping bubbles when you lay it down; they are easy to remove). Soap on the top of the film prevents you from scratching it while squeegeeing the excess solution and bubbles out. Reapply soap as you work. Expect to spend about 5 minutes working out the bubbles.
The BDF film came with a razor knife and mini-squeegee. They worked well, but we found a box cutter with a pristine blade was better and didn’t use the supplied blade. A good shower squeegee works just as well, and we alternated.
LONG TERM RESULTS
Both products looked sharp to start, with no imperfections or bubbles.
At the 5-month mark a micro-hex pattern appeared on the Vvivid hatch, but it got no worse and there was no damage to the plastic hatch glazing when we peeled up a corner at the 1-year mark.
The BDF film has a harder surface and does not stretch at all. It also resists scratches. Both of our tinted samples flipped over in a thunderstorm, and neither bore any marks.
For 6 months the BDF looked perfect, but then bubbles and wrinkles started to appear, becoming severe at the 1-year mark. The failure was probably caused by outgassing from the polycarbonate glazing.
insulation are hatch covers. Outland (top) supplies custom-covers (see “Outland Hatch Covers Impress,” PS March 2016).
Neither product damaged the plastic glazing.
In terms of UV blocking, both products are rated to block more than 95 percent of rays.
CONCLUSIONS
We’re impressed with the polyurethane Vviv id Headl ight film. The stuff is designed to survive on plastic on the front end of a speeding car, which is a tough test. A similar product, polyurethane tape that we applied to prevent chafe on our mast, is still going strong after two years (see PS December 2020, “Chafe Tape Plan”).
We would stay away from polyester films and only consider films that are rated both for exterior use and plastic glazing. We’re not sure how long the film will last, but we’re comfortable projecting at least 3 years. If we had any clear hatches on our boat, we’d give it a go, in hope of improving lens longevity and keeping UV and heat out of the cabin.
VALUE GUIDE: PORTLIGHT AND HATCH TINTING OPTIONS
| BRAND | VVIVID | BDF |
|---|---|---|
| MODEL | Smoke Black Adhesive Headlight Film | Ex 15 Exterior Film Silver Dark |
| MATERIAL | Polyurethane | Polyester |
| MIRROR | No | Yes |
| PRICE | $19.99 | $29.00 |
| WIDTH | 16 in. | 12 in. |
| LENGTH | 96 in. | 50 in. |
| PRICE PER SQUARE FOOT | $1.87 | $6.96 |
Mirror vs. Gray? Both looked sharp to start, with no imperfections or bubbles. Personal preference, but the Vvivid smoke looks just like a factorytinted hatch. Additionally, the mirror coating reduces permeability and may lead to bubbling.
Vvivid film is noticeably thicker. Polyurethane films, like the ICS Race Tape we tested for abrasion and ding protection (see “Chafe Tape Plan,” December 2020) are able to self-heal rock dings, and the Vvivid film did well with sticks and acorns. The Vvivid- coated hatch flipped over in a July thunderstorm, but the abrasive asphalt shingles did not scratch it noticeably. Polyurethane films have better flexibility around compound curves and thermal expansion.
1. The Vvivid smoke black film applied easily and has so far lasted. From six feet it looks factory finished and after two years in the sun, no bubbling, scratches or cracks are evident.
2. The BDF film offered more privacy but the quality of the film itself fell short of our expectations.
