Header for print stylesheet
Go

Trouble shooting

For getting the maximum performance out of a gelcoat, good workshop practices are essential. If gelcoat is applied in a wrong way, it will create problems that often only appear after the product has been demoulded. This trouble shooting guide will help you in identifying the problems, what could have been the cause and the remedies to prevent it from happening again.

Alligatoring / Wrinkling

Effect - Wrinkling of gelcoat in contact with the mould. Air or laminating resin may be trapped in ridges on the wrinkles.

Cause Remedy
Insufficient film thickness Apply recomended thickness (400 -600 micron)
High humidity Install dehumidifiers or work in a less humid environment
Low temperature Increase the room temperature
Too low catalyst level Increase catalyst level
Too long gel time Check catalyst level
Insufficient cure time before back up Check catalyst type / level / temperature

Pinholes / Porosity

Effect - Micro-holes in the gelcoat surface caused by very fine entrapped air bubbles.

Cause Remedy
Gel time too rapid for air release Review catalyst type / level
Catalyst overspray Check for alignment on external mix guns
Poor automisation on spray Check and adjust pressures (fine porosity generally due to excess pressure). Coarse porosity insufficient pressure. Film thickness must be reached with at least two passes. Allow more deareation time between passes.
Gun to close the mould Hold the gun 50 - 100 cm from the mould
Gelcoat film too thick Apply recomended thickness (400 -600 micron)
Viscosity too high Check viscosity and temperature

Cracks & Crazing

Effect - Cracks and crazing on the gelcoat surface. Patterns give clues as to cause. Spider cracks: impact from aminate side, concentric cracks: impact from the gelcoat side, parallel cracks: due to excessive flexing.

Cause Remedy
Excessive force used in demoudling Do not hit the mould or moulding with a hammer etc. Demould by using compressed air or water
On demoulding
Too much gelcoat Check film thickness
Gelcoat too rigid use a more flexible grade
Back-up under cured on demould Check barcol hardness. Demould when the laminate is perfectly cured
Release agent problems Check that the release agent and its application are correct
Cracks in the mould Check that the problems are not in the mould surface

Cracks & Crazing

Effect - Cracks and crazing on the gelcoat surface. Patterns give clues as to cause. Spider cracks: impact from aminate side, concentric cracks: impact from the gelcoat side, parallel cracks: due to excessive flexing.

Cause Remedy
Excessive force used in demoudling Do not hit the mould or moulding with a hammer etc. Demould by using compressed air or water
On demoulding
Too much gelcoat Check film thickness
Gelcoat too rigid use a more flexible grade
Back-up under cured on demould Check barcol hardness. Demould when the laminate is perfectly cured
Release agent problems Check that the release agent and its application are correct
Cracks in the mould Check that the problems are not in the mould surface

Cracks & Crazing

Effect - Cracks and crazing on the gelcoat surface. Patterns give clues as to cause. Spider cracks: impact from aminate side, concentric cracks: impact from the gelcoat side, parallel cracks: due to excessive flexing.

Cause Remedy
Excessive force used in demoudling Do not hit the mould or moulding with a hammer etc. Demould by using compressed air or water
On demoulding
Too much gelcoat Check film thickness
Gelcoat too rigid use a more flexible grade
Back-up under cured on demould Check barcol hardness. Demould when the laminate is perfectly cured
Release agent problems Check that the release agent and its application are correct
Cracks in the mould Check that the problems are not in the mould surface

Gelcoats

footer for print stylesheet