Nupol Composites

Nupol Composites
49-61 Stephen Road,
Botany, NSW, 2019
Australia
Phone: +612 9666 0331
Fax: +612 9666 3872

Application

Applications > Troubleshooting > Gelcoats & Flowcoats Moulding Surfaces

Gelcoats and Flowcoats Moulding Surface

OBSERVATION	POSSIBLE CAUSES	REMEDIES
Soft dull gelcoat - triping (wrinkling)	Insufficient coverage Slow gel or cure Low temperature Trapped styrene	Apply a total of 0.7 mm wet film in 3 passes. Increase catalyst to maximum 2%. Gelcoat and mould bust be min. 15^oC. Hold gun at least 50 cm away from mould. Adequately ventilate, or tilt mould to expel styrene vapour, after gelation.
Sticking to mould - fibre pattern	Excess styrene evaporation Uneven gelcoat Wet PVA release agent Water/Oil in air lines. Laminate applied too soon Laminate too slow to cure	Do not use over 30^oC. Apply at uniform distance from mould. Dry thoroughly Flush out and drain traps. Do not laminate for 2 hours. Increase catalyst in laminate if temperature low.
Dull part when pulled	Wax build up on mould Polystyrene build up on mould Dust on mould Rough or wet PVA Raw catalyst	Polish mould. Scrub with stiff bursh or stainless steel wool and strong solvent. Reubff and repolish. Keep mould covered when not in use. Apply smoothly and allow to dry. Atart catalyst flow away from mould.
Pre-release or delamination	Allowing gelcoat to cure too long Use of waxed gelcoat Excessive or soft wax on mould Excessie styrene added Over catalysation at high temp Uneven cure due to uneven thickness Uneven cure due to styrene vapour in low spots	Gelcoats must be laminated same day. Do not used waxed gelcoats on mould Polish mould before use Add maximum 2% styrene Reduce catalyst to 1% minimum Apply gelcoat to uniform 0.5 mm - 0.7 mm thick Avoid heating or fan blowing before gelatoin. Ventilate mould properly.
'Fish eyes'/ pin holes	Sililcone in wax or polishing cloth Contamination on mould Excessive thinning of gelcoat Thin gelcoat Gun pressure too low	Eliminate silicones in contact with mould. Keep mould covered when not in use. Thin with maximum 2% styrene. Rotate stock, contact supplier. Increase pressure to obtain good fan.
Crazing	Too much catalyst in hot weather Applied too thick Bad handling when demoulding Applied unevenly Thinning with acetone or other solvent	Reduce catalyst to minimum 1%. Maximum 0.7 mm wet thickness. Demould carefully. Keep consistent distance from mould when spraying. Thin only with styrene monomer.
Blisters, Bubbles	Air traped between gelcoat and laminate Over catalysation Poor catalyst dispersion in gelcoat and laminate	Remove with roller. Use maximum 2% catalyst. Mix thoroughly.
Scratched gelocat	Removal of finished article from mould	Sand back, buff and polish.
Fading or bleaching	Poorly cured gelcoat Exposure to harsh chemicals	Refer to remedies "Soft Dull Gelcoat". Refer to supplier.

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