Thanks, this is very helpful to me. It sounds like you did the blister repair in the best possible manner by building up glass and vinyl ester followed by the epoxy
. I have since found examples where this same system of repair has lasted 20+ years which is a huge improvement over the epoxy only coatings.
The type of delamination
you described is also somewhat reassuring to me. Once the gelcoat
sprayed into the mold
has cured, a single
layer of 1.5 ounce matt is normally laminated to the gel coat and allowed to cure. It is quite easy to see and to remove air bubbles in this thin layer of glass so that you don't have air bubbles right under the gelcoat
where they can easily break open and this layer protects the gel coat from damage during the heavy layup
. Then the heavy structural laminations are applied, normally in stages to reduce heat build up and shrinkage. In your case, it sounds like the initial skin out layer of glass was either not sanded, or perhaps was too cured to bond well with the succeeding laminations so it was easy for osmosis
to break the bond. Since the
blisters apparently were only in the gelcoat and the initial skin out layer, the structure was fine and now you have glassed over the hull
with a superior resin which mimics the construction method of a number of other high quality builders like Hallberg Rassy
which don't seem to have a blister problem. While I have not used vinyl ester to date for blister repairs
, I have reconstructed a number of decks with core issues using this resin and it really seems to bond well to the original fiberglass
laminate. I made up a number of samples where I scarfed vinyl ester/ glass layup
to the original layup and after a full cure did some destructive testing. The samples never broke on the scarf, it was always in the original layup which told me that the repair was better than the original material.
PS, I am short time right now but I am anxious to read more of your posts on CF about using the Lithium, Iron Phosphate batteries on your boat!
Originally Posted by s/v Thea
As far as I can remember the peel removed all the blisters, there was some poor bonding in the mat layer and they were able to manually peel off large sheets
of mat. They ended up peeling most of the mat then replacing mat using vinylester resin, then epoxy over top. After 4-1/2 years no signs of any more blisters.
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