Caulking the Deck Seams

After the varnish is laid on, but before the final coat, it’s time to caulk the deck seams.  Most of them (2 out of 3) are false seams–only there for show.  But every third one is live.  It is essential to get a good seal with the seam caulking to prevent leaks and rot.  

I use Sikaflex 291 LOT (long open time) which is a medium strength adhesive caulk.  It remains flexible throughout its long life, and is easily tooled with an extra caulk tube tip to give you the concave surface you’re looking for along the seam.

On old deck seams, it’s not a bad idea to use mahogany colored caulk, and then paint it white with a paint striping tool.  This isn’t as difficult as it sounds.

The Beugler paint striping tool is pretty amazing, and fairly easy to work with just minimal practice.  It’s the tool professional auto-body workers use to add those fancy pin stripes to cars.  You really won’t believe how easy it is to get great results with this tool until you try it.

So I caulked all the straight seams first, letting that set up a day.  Then I went back and finished off the curved outline seams.  It’s easier to correct mistakes if you’re not intersecting with wet caulk.  Same logic applies to the painting.

Then, once the paint is well cured, a final coat of clear urethane over the whole boat will seal the caulk seams and keep them from getting dirty.