Although GRP Fibreglass is relatively easy to use, there are a few indicators of incorrect use. This section is designed to help you troubleshoot your problems. Identify your problem below and rectify with the suggested information following the diagnosis.

Wrinkling, Rippling or Orange Peel Effect
Often caused by under cure of the gelcoat layer. Check your catalyst addition level as well as you mixing efficiency. Avoid operating under damp or cold conditions

Blistering
Air trapped between gelcoat and laminate or contamination with water or solvent. Apply a generous layer of resin on the gelcoat layer and bring it up and through the mat. Make sure the mould, brushes and rollers are not contaminated.

Fish Eyes (Lace Curtain Effect)
The gelcoat is not wetting the mould surface properly. Avoid the use of waxes or polishes containing silicone.

Colour Streaking
Caused by pigment separating from the gelcoat or never properly mixed in the first place. Check pigment addition level, stir very well and consider spray application

Fibre Pattern / Print Through
Gelcoat is too thin or under cured before beginning lamination. Allow it to reach full green cure before laminating, thicken the gelcoat layer and avoid damp cold conditions

Pinholing
Air bubbles are trapped between the mould surface and gel layer. Ensure you don't beat air into your gel when mixing catalyst or pigment. Lay the gel with light even strokes and do not stipple. Consider spray application. This may also be caused by dust on mould surface. Ensure its dust free using a tak rag or similar.

Flaking Gelcoat
There is poor adhesion between the gel and resin/mat laminate. Do not leave the gel too long before beginning lay up and certainly never more than 12 hours. It can also be caused by contamination of the gel layer before layup begins.

Star Cracks Hairline Cracks
Caused either by a sharp object impacting the gelcoat front side of the piece or a heavy blow to the reverse of the laminate structure. Be careful when demoulding and handling. Hairline cracks are caused by over needing the piece on demould. Apply even pressure at several points rather than pulling hard at a corner.

Distortion or Discolouration
Most likely the laminate has been exposed to excessive heat during cure. Adjust your catalyst (lower it!) or reduce the thickness of each layer of glass

Delamination
Caused by either contamination causing resin not to bond to gelcoat, or by a lack of resin. Can also be caused by a lack of wetting out of the mat itself. Ensure even and sufficient wetting out and roll carefully.

Tacky Finish
If the gelcoat is being used as a topcoat it should contain wax to stop cure inhibition by moisture in the air. If the reverse of the laminate is tacky try adding wax to the final resin coat on the back side.

Distortion
If the cast deforms post demould try adding ribs or a resin rich layer to balance off the effect of the gelcoat. Also ensure that its cured sufficiently before demoulding.

Poor Hardness or Rigidity or Failure to Set in Whole or Part
Most likely is either catalyst not mixed fully or not at right ratio or the glass is contaminated by water. Check you catalyst addition level (did you actually add it?), keep your glass dry, ensure the mould is dry and try not to lay up under cold and damp conditions.