fiberglass crazing
 

I am looking at two older sailboats, 69 South Coast 23 (daysailor) and
a 79 Oday 23, both have some crazing but none that seems structural.
Is there any easy remedy for sealing crazing and and what are the
ramifications for leaving it unattended? Does anybody have an opinion
about the two boats?

fiberglass crazing
 

There are two kinds of crazing:
1. One type looks like spider cracks due to stress relief of poor
design, impact, etc. Beware of spider cracks that are near bulkheads and
other sturctural members. If the under-structure is sound then is easy
repaired by gouging out the crack and refilling with gelcoat. A good
fiberglass restorer usually will have no difficulty in this repair.
2. Micro-cracks, typically found with a magnifying glass or low power
microscope. This is when the fiberglass gel coat has gone into total
failure due oxidation deeper than just surface oxidation. The stages are
heavy oxidation/dulling (recoverable) of the surface, followed by deep
oxidation that penetrates a now porous gelcoat. Repair is usually by
sanding off most of the gelcoat followed by painting. The cause is
failure to regularly seal the gel coat with WAX.

nortyler wrote:
I am looking at two older sailboats, 69 South Coast 23 (daysailor) and
a 79 Oday 23, both have some crazing but none that seems structural.
Is there any easy remedy for sealing crazing and and what are the
ramifications for leaving it unattended? Does anybody have an opinion
about the two boats?

fiberglass crazing
 

On Wed, 30 Jul 2003 00:53:28 GMT, RichH wrote:

There are two kinds of crazing:
1. One type looks like spider cracks due to stress relief of poor
design, impact, etc. Beware of spider cracks that are near bulkheads and
other sturctural members. If the under-structure is sound then is easy
repaired by gouging out the crack and refilling with gelcoat. A good
fiberglass restorer usually will have no difficulty in this repair.
2. Micro-cracks, typically found with a magnifying glass or low power
microscope. This is when the fiberglass gel coat has gone into total
failure due oxidation deeper than just surface oxidation. The stages are
heavy oxidation/dulling (recoverable) of the surface, followed by deep
oxidation that penetrates a now porous gelcoat. Repair is usually by
sanding off most of the gelcoat followed by painting. The cause is
failure to regularly seal the gel coat with WAX.

Gel coat is un reinforced polyester resin, and over time, especially if a too
thick layer was applied (early sixties boats tended to suffer from this as
fiberglass technology was still somewhat experimental then) it can craze due to
age (UV damage) and thermal stress from normal daily temperature variations.
Poor quality gel coat can also be susceptible to crazing. Wax has little to due
with preventing crazing due to these factors. It will keep it looking good
longer (i.e. glossy) , but not forever.

JJ


nortyler wrote:
I am looking at two older sailboats, 69 South Coast 23 (daysailor) and
a 79 Oday 23, both have some crazing but none that seems structural.
Is there any easy remedy for sealing crazing and and what are the
ramifications for leaving it unattended? Does anybody have an opinion
about the two boats?

James Johnson
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