A surprise awaited us a month ago when we hauled the boat after three years in the water. A whole bunch of small blisters were on the hull below the waterline. More appeared as the days passed and even as the light changed while I worked on sanding and "picking" at them to get to epoxy that would stick to the hull. These all started smaller than the diameter of a pencil, many of them much smaller. A little water was present in probably 85% of them, and we could often detect the faint vinegar odor of "spoiled" fiberglass resin.
I may be approaching 'boat pox' with this many blisters, but right this minute I am unwilling to spend the cash to have the epoxy bottom removed and a new one applied - I'll have to pay the pros to do this. The WEST System epoxy job is about 13 years old and is thin in some spots. My thinking is to do a good, and hopefully permanent, repair on these areas using a newer epoxy, and then see what the next haulout shows in a couple years. Meanwhile we'll save for a winter haulout and completely redo the bottom, in case we have a relapse.
The pictures attached show some of them, especially some of the clusters. The moisture meter readings were donated by the yard and were completed when I was about 75% done sanding. I was not present to observe the meter readings. Areas above 7% moisture were marked. The range is 8 to 17%.
I have been doing some reading about blister repairs, and more importantly, trying to determine whether to grind, and how deep and wide to grind when that is indicated. I seldom bring a problem to the board without some thinking being done by reading past threads, and without some plan for you to poke holes in.
Questions:
1. How can I tell where I should be grinding? Is sounding sufficient? Should moisture readings be a major guide and what is a bad moisture reading? I have heard moisture readings done badly can be misleading.
2. When I do grind, how can I tell that I am deep and wide enough? One method I read involves hardness readings and additional moisture measurements as you go. Individually these don't seem too bad, but the clusters bother me.
3. Is the 2000E epoxy among the best for the epoxy or should I go back to WEST System with colloidal silica thickener?
Thanks in advance for your reactions and recommendations.
I may be approaching 'boat pox' with this many blisters, but right this minute I am unwilling to spend the cash to have the epoxy bottom removed and a new one applied - I'll have to pay the pros to do this. The WEST System epoxy job is about 13 years old and is thin in some spots. My thinking is to do a good, and hopefully permanent, repair on these areas using a newer epoxy, and then see what the next haulout shows in a couple years. Meanwhile we'll save for a winter haulout and completely redo the bottom, in case we have a relapse.
The pictures attached show some of them, especially some of the clusters. The moisture meter readings were donated by the yard and were completed when I was about 75% done sanding. I was not present to observe the meter readings. Areas above 7% moisture were marked. The range is 8 to 17%.
I have been doing some reading about blister repairs, and more importantly, trying to determine whether to grind, and how deep and wide to grind when that is indicated. I seldom bring a problem to the board without some thinking being done by reading past threads, and without some plan for you to poke holes in.
- I've completed the initial sanding around each, the results are as you see in the pics. There are some that show white glass fibers at the surface.
- I have sounded most of the areas of the hull with the back of a screwdriver handle and found that almost all of these areas have no change in sound across them, at least not to my ear. I will re-do this as I prepare to address each one. I am encouraged by this, but ...
- Those areas with a perceptible sound change will be investigated by some exploratory grinding. Exploratory grinding into layup will of course result in repairs with glass cloth and epoxy. 12:1 and 20:1 are mentioned as grinding diameters if I have to go deep.
- I have purchased Interlux 2000E epoxy for the repair. I've used this in the past for recoating the bottom in several small areas the last time we were out of the water for paint.
Questions:
1. How can I tell where I should be grinding? Is sounding sufficient? Should moisture readings be a major guide and what is a bad moisture reading? I have heard moisture readings done badly can be misleading.
2. When I do grind, how can I tell that I am deep and wide enough? One method I read involves hardness readings and additional moisture measurements as you go. Individually these don't seem too bad, but the clusters bother me.
3. Is the 2000E epoxy among the best for the epoxy or should I go back to WEST System with colloidal silica thickener?
Thanks in advance for your reactions and recommendations.