: After applying the last coat of MAS epoxy on the deck and waiting 3 days. I
: took my Expedition outside in the sun (80 degrees ). After 30 /45 minutes,
: I noticed a small area of raised ridges in the fiberglass 8 to 10 inches
: long. Th ridges can be seen and felt to the touch. They run along the
: seams of western cedar strips glued 8 months ago (Elmers yellow wood
: glue).
: Ideas?
: Corrective Measures?
: Cure?

Rob's explanation of creep is probably correct. I think in the long run a certain amount of creep is almost inevitable. Even if you find a glue that is immune to creep, I suspect that the presence of glue between the wood strips will tend to eventually cause some kind of visible line along the strip edges if only due to different expansion/contraction rates of the wood and the glue.

One thing I have taken to doing which may or may not make a difference with the lines but has other uses is: when I'm done with the fill coats I bring the boat outside and wrap it in black plastic and leave it in the sun all day.

This heats the whole boat up to 100 degrees F or higher. This helps accelerate the cure of all the epoxy in the boat. Even when the epoxy seems fully cured it can still cure more. It also heats up the glue between the strips and it wants to creep a little it provides a good opportunity before I have taken the time to try and sand it smooth. It also seems to help limit the amount of print-through of the cloth texture which also seems to happen after the finished boat has been out in the sun a while. And if none of these rationalizations work, it does let me sand a slow curing epoxy sooner.

I think the real solution to avoiding the ripple along the strip edges is to make your joints as tight as possible. This limits the amount of glue in the joint and minimizes the structural impact of that glue. With less glue, there is less stress on the glue itself and less likelihood that the glue will creep. I try to put just enough glue between the strips to hold the boat together until the glass is on, I then squeeze the joint as tight as I can. Too much glue will limit your ability to squeeze the joint tightly.