Chip,

It sure does look like the result of a combination of heat and some kind of physical stress. Maybe the boat was sat on while hot, or stress was built into the area during construction, or glass fibers were sanded into alowing moisture intrusion (through the varnish) which expanded during a heating phase. Notice that most of the problem is along the strip joints. This suggests that the strips are trying to move relative to each other. Only the builder knows which of the possible causes are most likely.

For a cure, I don't know any approach other than sanding the offending areas off. If they are extensive, it might be easier and better looking to remove the glass from all of the boat. If heat is a problem in the builders area, I suggest using a resin that has a high heat deflection temperature. If I remember correctly, MAS is around 132 degrees fahrenheit and System Three Clear Coat around 129. Some are closer to 100. I don't know what Raka's is, which is why I don't use it. It's pretty easy for a boat setting in the sun to get over 100 degrees.

Sorry I don't have a less painful answer.

Ted

: Occaisionally builders contact me offline with questions. Here is one that I
: thought the Group could answer better than I. I thought it looked like
: some type of stress fracture. Here is the original text of the question:
: Hi Chip,
: I am getting ready to start a kayak....I finished a Bob's Special canoe in
: November but just like everyone else I can't wait to start the next
: project. However, I have a problem with the glass on my canoe and don't
: want to have the same problem on my kayak. so I'm hoping that you can give
: me some advice. I had no problems with it in 15 half day trips. The
: weather was on the cooler side (65-75 degrees) when it got hotter (85
: degrees plus) is when I first noticed the problem. It seems that gas
: bubbles or something has appeared under the cloth from pinhole size to
: several inch lines that follow the wood joints. First, I am wondering your
: opinion on sanding off the glass and re-doing it or do you have any other
: thoughts?

: Second, I am wondering what I need to do that is different on the next
: project. Do you think that pre-epoxying would help? I used Raka 1-2 mix. I
: included two pics of the problem.

: http://www.chipsandresky.com/cedarstrip/images/conoeprob.jpeg
: http://www.chipsandresky.com/cedarstrip/images/canoeprob2.jpg