Scott Bader 337.
An Isophthalic Gelcoat for brush application. It has been carefully formulated to give excellent brushing properties. The thixotropy has been adjusted to minimise sag on inclined and vertical surfaces.
Approved by Lloyd’s register of shipping for use in construction of reinforced plastic craft under their survey, and is widely used in the marine and construction industry.
Coverage is approximately 600g per Sq Mt, dependant on operating temperature, therefore 1/2 Kg will cover approximately .8 Sq Mt.
If applying Gelcoat into a fibreglass (GRP) mould you must always add 2% catalyst, this will prevent the styrene present attacking the waxed surface which ensures the release of the part.
When the Gelcoat is tacky (approx 2 hours), you can then start placing and laminating your reinforcement. Never leave more than 24 hours between Gelcoating and laminating as the adhesion will be dramatically reduced.
The Difference between Gelcoat and Resin
A gelcoat would normally have about 3 times more thixotrope than a typical laminating resin. This increase in thixotropy means that the gelcoat can be applied to the recommended thickness of 0.4 - 0.6 mm in a single continuous film without drainage on vertical or inclined surfaces. The laminating resin could not do this, and obviously the gel coat would not wet out glass reinforcements as a laminating resin does.
Full drums of gelcoat are available with or without catalyst.