[C320-list] Question abouts Blisters on Early Models

[Dave Hupe]

 I have had my C320 (1994 #32) since early 2017 now.  It is in fresh water from usually late April through September.  Based on my early research, I believe my boat does NOT have vinyl ester (which I understand gives superior blister protection).  Instead, our early boats (before April 1995 from my research) used a "gel kote of Blister-Guard" (by Glidden) that was reportedly the "ultimate protection against osmotic blisters".  
Until haulout last year, my hull previously showed no blisters, other than a few rough areas that looked like a "rash" (maybe just in the paint).  However, then I counted about 60 total blisters, but they were all very small (maybe pencil eraser size maximum in diameter and only slightly raised).  The majority were located on the forward starboard side (forward of the boat's cradle pad on the forward, starboard side). I believe this concentration may have been related to water inside from an ongoing leak in a front pulpit leg that was hard to diagnose/pinpoint (but I can't confirm the relationship between this leak that I ultimately resolved, and the blistering). 
At the end of last season (after haulout), per a reference on blister repair, I chipped open and sanded/ground out all the small blisters.  Only 2 of the 60 had any seepage at all (which I understand can be the bad aspect, since this seepage can be acidic and widen the blister).  After sanding them open, I had areas to repair that were very shallow and maximum maybe a penny in diameter. I thoroughly washed these areas with water and a scrubby pad to remove any acidic residue.  I left the sanded opened areas unrepaired until this Spring (this exposure supposedly is fine).  
This Spring I scrubbed the areas again with fresh water, allowed them to thoroughly dry, painted/prepped the blister areas with a coat of unthickend epoxy, then applied thickened epoxy to fill the depressions, sanded smooth, then finished by rolling over with a paint of unthickend epoxy.  Ultimately I applied my bottom paint directly over this repair (after washing with water and using a scrubby pad to remove the epoxy wax amine). 
In retrospect, I wonder if these blisters were what have been referred to as "paint blisters" and may have been largely cosmetic. I will be interested to see what conditions I have after haulout this year. 

Dave Hupe1994 C320 (#32)Holland, MI