UP Pre-gel GRT35 white

Typical applications

• Surface coatings for composite components in glider construction
• Surfaces in model aircraft construction
• Gelcoat for compatible epoxy and polyester laminates
• Topcoat on fully cured laminates
• Repair and maintenance work on suitable surfaces

Processing

The gelcoat is already pre-accelerated with cobalt. A suitable hardener matched to the resin system is required for curing. The hardener dosage and working time depend on the product-specific instructions and the respective processing conditions.

Application

The gelcoat is preferably applied by spraying. Alternatively, it can be applied using a brush, roller or spatula. The optimum processing temperature is 20–25 °C. When used as a gelcoat, the mould temperature must be at least 20 °C.

Multiple spray coats should be applied wet-on-wet. Allow approximately 5–10 minutes of flash-off time between coats. Layers that have already started to gel must not be recoated immediately, as the styrene contained in the fresh gelcoat may partially dissolve the underlying surface.

Overlaminating with epoxy resin

Before overlaminating, the gelcoat must have gelled sufficiently. At this stage, the surface has a uniform matt appearance and no colour transfers when touched.

When combining the gelcoat with epoxy resin systems, adhesion and compatibility must be checked by preliminary tests. Incompatible combinations may cause discolouration, cracking, blistering or adhesion problems.

Use as a topcoat

When coating previously cured epoxy or polyester laminates, the substrate must be dry, clean, adequately sanded and fully cured. Epoxy resins that have not fully cured may interfere with the curing of the gelcoat.

Sanding and polishing

After complete curing, the surface can be sanded and polished to a high gloss. Before polishing, the manufacturer recommends wet sanding with 1000 grit, preferably 2000 grit abrasive paper. Avoid localised overheating during machine polishing.

Storage

Store the pre-accelerated gelcoat in a cool place in a tightly closed container. According to the manufacturer, the shelf life is approximately 6 months below 10 °C or approximately 3–4 months at 10–20 °C.

Surface care

To maintain the surface over the long term, regular care with suitable silicone-free paint care products containing UV protection is recommended. Water and mild cleaning agents are suitable for cleaning.

Application limitations

The gelcoat is only conditionally suitable for prolonged outdoor weathering and is not intended for component surfaces exposed to permanent water contact.

Safety information

Observe the processing and safety instructions for the hardener used, as well as the safety data sheet for the gelcoat. Organic peroxide hardeners must never come into direct contact with accelerators. There is a risk of explosion.