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Rosehill Industrial Estate, Ballinacurra, Midleton, Co. Cork, P25DH26.  Call us now on +353214631711 or email info@grs.ie

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working-with-glass-fibre-resin

For Smooth-On Product Technical Information, Please consult their website www.smooth-on.com

Calculating Quantities of Glassfibre , Resin, Flowcoat and Catalyst

To Calculate the quantities of glassfibre, resin, flowcoat and catalyst the following method should be used:

Calculate the total area in m² of glassfibre required for the repair, allowing for overlaps, extra layers etc. 1m²= approx.10ft²

  • From the area required, weight of fibreglass be can calculated, depending on the grade of material to be used: CSM 450= 450g/m² i.e 1m² of fibreglass weighs 450gms, CSM 600=600g/m² i.e. 1m² of fibreglass weighs 600gms
  • The ratio of resin : fibreglass is approximately 2.5 : 1 i.e 1 kg of fibreglass requires approx. 2.5kgs of resin.
  • Flowcoat will give a coverage of approx 0.5-0.75kg/m² i.e. 1 kg of flowcoat will cover approx. 1.5m² to 2m²
  • Catalyst should be added at between 1% and 4% by weight depending on ambient conditions and cure time required. The standard addition rate is 2% (=20gm catalyst per kg of resin)

The ratio applies to all polyester resins, gelcoats, flowcoats etc. unless otherwise specified. Too much or too little catalyst will inhibit cure, while gel time is adversely affected by high humidity and low temperature.

Working with Glassfibre

General Instructions for working with glassfibre

  1. Work in dry, well-drained and warm conditions. Dampness and cold inhibit cure.
  2. Protect yourself and your clothes. Wear gloves. Wear a fume mask if working in enclosed spaces. Protect your eyes from contact with resin, catalyst and acetone.
  3. Thoroughly prepare surface to be worked on, removing all trace oil. dirt, water etc. For repairs to existing GRP ensure a good key is obtained by aggressive sanding with coarse grit sandpaper.
  4. Have everything ready before starting work: cut glass mat to size. Pour the required amount of resin into a container. Have a jar of acetone ready to clean the brushes and rollers after use.
  5. Add hardener to the resin accurately and carefully – too much will prevent a cure, too little will retard it. As a rule of thumb 20cc of hardener to 1 Kilogram of resin should be used, giving a pot life of about 20 minutes at 20 deg C. In warm weather reduce this to no less than 10cc per kilo and in cold weather increase it to no more tha 30cc per kilo. Only catalyze as much resin as can be used within the pot life.
  6. Using a brush or mohair roller, apply the resin evenly over the surface of the fibreglass. Lay down the glass mat and apply more resin, spreading out liberally and evenly over the mat. Using a paddle roller, or stippling with a brush, thoroughly ‘wet-out’ the glassfibre, so that the glass is fully impregnated with resin and all air bubbles removed.
  7. Wash out brushes and rollers thoroughly in acetone after use. To save for reuse follow this by washing in warm soapy water and allow to dry.

Health and Safety

Please refer to the labels on the resin, catalyst and acetone containers and note the hazardous nature of the products and the safety precautions to be taken when using them. For further information refer to the relevant MSDS (Material Safety Data Sheets) – available on request.

Keep all materials out of the reach of Children.

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