Guide to bonding marine windows using Sikaflex

Some people argue against using the expensive stuff like Sikaflex and Awlgrip but whenever possible, I've always thought it wise to stick with industry standard products when building a blue water boat.  Since this boat is being built to provide safety and comfort for my family, I buy the best materials available.

here's the link:



The one thing that seems sketchy about the install directions is the need for an external coating of protective paint around the window edges.  You would think that Sikaflex UV would not require this but I  have been advised by a renowned west coast yacht builder NOT to skip this step.  They did an install without doing this and the boat came back for a complete window rework at the yards expense.

Here's a handy illustration of the best practice install:


Prepping for the window install

All of the windows were CNC cut from hard coated Acrylic.  The forward windows are 3/8 inch thick for added strength.

Here are the steps that I will follow to install the windows:

1  drill holes in edges of windows
2   drill matching holes in boat
3  mark outer UV paint marks around edges with tape
4  remove windows
5  paint outer edges with black"fusion" plastic paint
6   clean openings with Sika cleaner
7  clean back side of window edges with cleaner
8  prime back side of window edges with Sika primer - 209D
9  apply bead of Sika Flex around opening
10  insert spacers and "o" rings around fasteners
11  fix windows in place
12  tighten fasteners  ( all 300 of them )
13 back fill any voids around edges
14  clean residue with mineral spirits
15  stand back and admire the fitted windows