Curing is boring and painting is risky

The fifth and final day of the filling, fairing and moisture barrier coating marathon was last Thursday. This means I am done with epoxy work until it is time to glue the top onto the boat. The finished surfaces need to cure about a week before scrubbing with water and surface preparation for painting.

It is time for paint decisions. The topside and hull of the boat are painted with Interlux Brightside one-part  polyurethane paint over Interlux Pre-Kote primer. I have a good supply of this stuff and I had planned to use it for the new top. However, a friend suggested that I consider a two-part  polyurethane paint. Two-part paints are generally harder and more durable.

Serendipity strikes again

I like hard and durable. So I went to the Interlux website to learn more about two-part paint. I am really glad I did that. I could have made a bad mistake.

 It turns out that the Interlux Pre-Kote primer I had planned to use is not compatible with epoxy surfaces. Interlux says that, over time, my epoxy-encapsulated top will slowly exude a nearly invisible substance called 'amine.' Amine can cause all but special undercoatings to separate from the epoxy surface. The last thing I need to happen is for the paint to peel off shortly after the new top is installed.

A long email exchange with a very helpful person named Jay at Interlux technical support resulted in discovery of a special primer that will work. So I have made a decision to go with Interlux Epoxy Primekote for the undercoat and Interlux Perfection, a two-part polyurethane, for the top coat. Special surface preparation will be required, before multiple applications of primer and finish coats. I will be ordering the paint and starting this work next week.


From the Sage Advice Department

If you are going to make a top this way be sure to make registration marks on the underside. When it comes time to put the top on the boat you can use these markings to line it up before you fasten it down.

The big cross mark in the foreground of this picture is to register the forward end of the top on the very front edge of the framework on the boat. The faint line running upwards is a chalk line I snapped down the center on the underside of the top after I finished the plywood glue-up, but before I applied the edging material. There is another cross mark at the other end of this center line, providing a line-up mark for the aft end of the top.

The five black dots mark where I will bore holes for the light mast brackets and the water tight 12-volt cable connector for the light mast. Locating these holes would have been risky guess work without the end marks and the center line.

And, meanwhile...

I will be applying the first of six Cetol finish coats to the light mast and the grab rails today -- right after I double-check the measurements on the template I made to locate those five black dots in the picture above. The mark on the far right doesn't look quite right.

Again, please share your advice, questions, concerns and suggestions. Use the comments box below.