Teak Caulk

Its time to check in on our teak caulk test after eight months. The seven test products, all marketed for use as teak deck caulks, held up well after load tests and being doused with chemicals.

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Teak decks can last a century, if theyre properly cared for, and a major factor in successful teak deck maintenance is choosing the right caulk-and applying it correctly. In June 2006, testers applied seven caulks used for teak deck seams to test panels. The products: Simson MSR (Marine Special Range) Deck Caulk Plus, Maritime Teak Deck Caulking, Teakdecking Systems SIS 440 Teak Deck Caulking, West Marines Multi Caulk Sealant, and three from BoatLIFE (Life-Caulk, Teak Deck Sealant, and Life-Calk Type P). We rated each for ease of application in the September 2006 issue, so after eight months, its time to take a look at their durability, adhesiveness, and resistance to chemicals.

 

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In June of 2006, we began our evaluation of seven caulks advertised for use in teak deck seams: Simson MSR (Marine Special Range) Deck Caulk Plus, Maritime Teak Deck Caulking, Teakdecking Systems SIS 440 Teak Deck Caulking, West Marines Multi Caulk Sealant, and three from BoatLIFE (Life-Caulk, Teak Deck Sealant, and Life-Calk Type P). The test group was a mix of polysulfide-, polyether-, Silyl Modified Polymer- (SMP), and silicone-based products, as well as both one- and two-part products.

Testing

Tests were designed to comparatively evaluate each caulks ease of application,

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durability, adhesiveness, and resistance to chemicals. We discussed the products ease of application in the September 2006 issue, so this and future updates will deal with durability, chemical resistance, and adhesion test results.

Durability

To compare durability, we applied the products, following manufacturers instructions, to seven 9-inch-long, 2-inch-wide, half-inch-thick teak planks that each contained a single square seam -inch-wide and -inch-deep running the length of the plank. After 14 days cure time, the panels were placed outdoors and fully exposed to the weather. We inspected them in January, eight months after placing them outside, to see how well each product was holding up.

Results

: Each of the seven products appears to be holding its own with no signs of deterioration or seam failure.

While all of the products have held up equally well so far, we did notice some differences. Some of the caulks seem more pliable than the others. Our softest caulk, the West Marine Multi-Caulk, had the resilience of a neoprene wetsuit, while

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our hardest caulk, the BoatLIFE Life Caulk, was slightly firmer than a pencil eraser. However, all had more than enough flex to handle joint expansion, so this observation may have little bearing on our results.

Chemical resistance

The goal here is to see how well each caulk holds up to chemicals one could reasonably expect a teak deck to be exposed to during its lifetime gasoline, diesel, motor oil, ammonia, household bleach, Cetol marine oil, acetone, Starbrite teak brightener (containing Oxalic acid), WD-40, brush cleaner, Fantastic, Murphys Oil soap, MEK, and a heavy-duty bilge cleaner from West Marine.

We used 16 teak panels (8 inches x 4 inches), each containing a 4-inch-long bead of each caulk tested. Of these, 14 were exposed to a single chemical, while the 15th was alternately exposed to all chemicals used in the test. The 16th panel was exposed to no chemicals. After a two-week curing period, all panels were located outside (fully exposed to the weather) and given the initial dose of their respective chemicals, after which the chemicals were applied bi-monthly and in such quantity as to thoroughly saturate each caulk bead and the test panel surface.

Results

: So far, so good. There are no signs of damage or deterioration on any of the panels at this stage.

Adhesion

To test adhesion strength, we mounted seven 2-inch-x-2-inch squares of teak on a 2-foot-long teak plank with walnut sized gobs of each caulk tested, once again following each manufacturers recommendations for surface preparation on new teak. The plank was then set aside for three months to ensure each caulk had plenty of time to fully cure.

Prior to being attached to the plank, each square had an eyebolt fastened through its center and secured via nut and bolt. After the three-month curing period, we braced the plank and suspended 35 pounds from each of the squares for five minutes and observed the results.

Results

: Each caulk-attached square held the suspended weight with no sign of failure.

Whats next

Well continue to monitor each plank and report the results in future updates. For chemical resistance testing, we plan to drench the panels in their respective chemicals. Then well embark on some destructive adhesiveness testing applying pressure to each caulked square until the point of failure. Stay tuned.

Darrell Nicholson
Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him by email at practicalsailor@belvoir.com.