This automotive windshield goop is cheap, effective, and durable
Issue 22 : Jan/Feb 2002
Do you have a leaky Lewmar hatch? Is it one of those intermittent drips that you can’t find? Has it reached the level of Chinese water torture? Does someone on your crew open the hatch by pushing on the glazing instead of the handles? Ah ha! You may have a capillary leak.
That’s what happens when the adhesive bond between the glazing and the rubber gasket has been broken, but the glazing stays in place. It seems to hold water when you hit it with a bucket, but over time capillary action pulls water molecules through the almost nonexistent gap. They collect on the inside until a drop forms, and the torture begins.
The obvious fix is to remove the glazing and reinstall it with 3M Weather-strip Adhesive. In spite of its name, it’s the right product for the job. It is made for installing windshields. Of course, if you’re like me, you will tear the old gasket when you remove the glazing, leaving a bigger hole in the boat while you wait for a new gasket to arrive. Another small job turns into a major project. That’s why we put up with so much water torture on boats.
There is another option: Re-glue the glazing in place. Permatex Flowable Silicone Windshield Glass Sealer (81730-65AR) is designed for this application. It’s thinner than what you would expect of a silicone product so it is able to flow into nooks and crannies. It is also the only weather-strip adhesive sold with a tip that lets you squirt it into small places. And it dries clear. At $1.99 for 1.5 ounces, it’s a cheap fix even if you use a whole tube on one job.
Tools: The glazing is a tight fit even if the adhesive bond has failed. It butts against the side of the L-shaped gasket on the outside of the hatch. You could use a bread knife to insert adhesive from the top. But it’s a different story from the bottom. You’re approaching the joint from the side with the glazing on top of it. You need something thin enough to slip into the gap and flexible enough to bend so the handle doesn’t press up on the glazing. Yet it has to be rigid enough to not distort when you slide the tool along the gasket. The tool of choice is an artist’s pallet knife. A short one is best. It’s worth it to buy one if you don’t have one left over from your student days on the Left Bank.
Technique: You’re trying to smear adhesive into the gap between the glazing and the gasket. Work from the deck with the hatch open. This allows you to look from the top while you work from the bottom. Probe with the blade to learn the extent of the gap you are going to fill. Once you have an idea of what you are working with, squirt a bead on the edge of the gap and smear it in with the pallet knife. The sides of the blade won’t carry much. This is an exercise in patience. Repeated strokes will push adhesive into the gap.
The filled areas will appear wet. You will feel the difference when the pallet knife needs more adhesive. It will move smoothly when it is wet and drag when it is dry. When the entire gasket area is smooth to the touch, repeat the drill from the top. With the hatch edges buttered on the sides and bottom, the leak will stop. The silicone will dry in an hour and cure in a day. It cleans up with paint thinner when wet and a razor blade when dry.
Is it a marine product? No. Then again, unless you’re a Vendée Globe competitor, your hatch isn’t going to see anything like the beating a car windshield takes from road salt, car washes, and highway wind speed. Car windshields don’t fall out on the coast, do they? This stuff was designed for the environment. It just doesn’t say “marine” on the label. It can be found in the adhesive section at Pep Boys.
Peter raced Lightnings during his formative years and spent a portion of the 1980s as a member of the Hudson River Sloop Clearwater Foundation. These days he spends more time in a sea kayak, an Old Town sailing dinghy, and a Newport 27s MkII. Along with the boat, Peter is nurturing a 1987 Avanti coupe and a 1967 Land Rover 109.
Thank you to Sailrite Enterprises, Inc., for providing free access to back issues of Good Old Boat through intellectual property rights. Sailrite.com
