Techniques; Gelcoat Touch-Up And Repair - Columbia Coronado 25 Owenrs Manual

TECHNIQUES

3.1 Gel Coat Touch-up and Repair
Minor abrasions and scratches can be removed from gel coat with an
abrasive automobile polish followed by a wax polish such as Johnsons "J
Wax Kit". More serious damage and flashing areas should be ground until
smooth and fair with a disk or belt sander using 60 grit cutting surface.
Any depressions should be filled with polyester body putty. Ample putty
should be applied to allow for some shrinkage. When the putty has hardened
it should be sanded in turn with 220 and 400 wet or dry sandpaper.
The gel coat should be applied next by using a spray gun. The Freon
propellant type guns are satisfactory. Thin the gel coat approximately
40 percent with acetone for spraying. Add one to two percent by volume
of catalyst. More catalyst causes the resin to set faster. Curing is
slower at temperatures below 70° and does not proceed satisfactorily
below about 57°. Temperatures between 700 and 57° may be partially
compensated for by slightly more catalyst. High humidity also interferes
with curing.
After the gel coat is sprayed on, a thin layer of mold release (5006
mold release liquid from Thalco Corp.) should be applied with the spray
gun to shut out the air and permit the gelcoat to cure.
Curing should be complete in about two hours. The release is water
soluble and can be easily washed off. Sand with 400, then 600, wet or dry
sandpaper and finish with a buffer.
For additional information concerning gel coat touch-up and repair,
consult Section 6.
NOTE: Ground fiber glass is an irritant to the respiratory
system and a mask should be worn when machine sanding.
Use separate cups for gel coat and release. Mix small
quantities only of gelcoat. Clean out cup and gun with
acetone at least once an hour. Mask off surfaces
outside the work area to prevent accidental overspray.
SECTION 3
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