GTS and R&G polyester casting resins are medium reactive unsaturated polyester resins that are pre-accelerated with cobalt. Their most distinguishing features are their transparency and their UV resistance. These polyester resins are crystal clear when cured but can also be coloured (dyes for synthetic resins) quite nicely - which accounts for the fact that they are so often used in model making as well in the decoration sector (e.g. for moulding objects).

As is the case with all polyester resins, the mixing ratios between resin and hardener are dependent on the amount being employed. The most accurate way to add the extremely small amount of hardener required as a percentage of volume is to use a pipette or a disposable syringe. Please take note of the following data when working with these resins:

Mixing ratios for polyester casting resin GTS:

Please note that when more that 2.5% hardener is added to GTS casting resin it will become yellowish. Too much hardener will also lead to very high temperatures which, in turn, will lead to cracking in the material. Amounts of hardener larger than 5% will make the resin soft.

The working time and the de-moulding time are also determined by the amount of hardener used. The following data are based on room temperature.

Data for polyester casting resin GTS (100 g mixture):

GTS can also be used as a laminating resin with addition of a reinforcement process that consists of applying the required fibres by hand.

We only offer the polyester casting resin R&G in large quantities because it is so much less expensive in bulk than the GTS resin. On top of that, the R&G casting resin can be used to make as large as a 5 litre block in a single pour without the risk of cracks developing in the material. If the heat that is thereby produced bothers you, layers of between 2 and 3 cm thickness can be poured one after the other as soon as the reaction heat has subsided for each segment. These casting resins should never be worked with in temperatures under 18 °C.