UP Pre-gel GRT35 white + MEKP Hardener

UP Gelcoat GRT35

MEKP Hardener

The general standard MEKP dosage must not be regarded as a product-specific, confirmed mixing instruction for GRT35.

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

Mixing and curing

The gelcoat is already pre-accelerated with cobalt. The MEKP hardener is carefully mixed in at the dosage specified for the resin system. Ensure thorough mixing while avoiding unnecessary air entrapment.

The hardener dosage and working time depend on temperature, batch size, layer thickness and other processing conditions. The specific dosage for the supplied system must be determined according to the product-specific instructions.

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.

Gelcoat 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.

Hardener storage

Store the MEKP hardener in a cool, dry place in its sealed original container. The stated minimum shelf life is 3 months in the unopened original container. Observe the hardener manufacturer's storage and safety instructions.

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. The operating conditions and any necessary protective measures must be taken into account for such applications.

Safety information

Organic peroxide hardeners must never come into direct contact with accelerators. There is a risk of explosion. If additional acceleration is required, the accelerator must be thoroughly mixed into the resin before adding the hardener. The relevant safety data sheets must be observed.