SikaBiresin® GC108

Epoxy gelcoat with very good heat resistance and polishable properties

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SikaBiresin® GC108 is a 2-component epoxy gelcoat with very good heat resistance and polishable properties.  

  • Polishable to high gloss (up to gloss value 85)
  • Good grindability
  • Heat resistance up to 130 °C
  • Dense surface and good edge stability
  • Good styrene resistance
 

Overview

PRODUCT BENEFITS

  • Polishable to high gloss (up to gloss value 85)

  • Good grindability

  • Heat resistance up to 130 °C

  • Dense surface and good edge stability

  • Good styrene resistance

 

Areas of Application

SikaBiresin® GC108 is designed for manufacturing of master models, gauges and vacuum forming tools. The Product is also well suited for production of negative molds in composites industry.  This product is suitable for experienced professional users only.
Tests under actual processing conditions and with additional materials such as coatings and release agents must be performed to proof material compatibility.  

Packaging

  

SikaBiresin® GC108 (A)

Pail

8 kg

SikaBiresin® GC08 (B)

Canister

1.6 kg

 

Product Details

Properties

Component A

SikaBiresin® GC108

Component B

SikaBiresin® GC08

Chemical base

Epoxy resin, filled

Amine, unfilled

Color

 

mixed

Black

Amber

Black

Density

  

cured

1.21 kg/l

1.0 kg/l

1.22 kg/l

Mixing ratio

by weight

100 : 20

Viscosity (CQP029-4 / ISO 3219)

 

mixed

Pasty

130 mPa·s

25 000 mPa·s

Pot life (CQP021-4)

200 g at 23 °C

30 minutes

Tack free time (CQP019-3)

at 23 °C

60 minutes

Demolding time

earliest after

16 hours

Shore D hardness (CQP023-1 / ISO 868)

86 A

Flexural modulus (CQP027-2 / ISO 178)

3500 MPa A

Flexural strength (CQP027-2 / ISO 178)

90 MPa A

Impact resistance (CQP038-2 / ISO 179)

9 kJ/m2 A

Compressive strength (CQP028-5 / ISO 604)

120 MPa A

Heat deflection temperature (CQP030-1 / ISO 75B)

130 °C A

Glass transition temperature (CQP301-5 / ISO 11357)

134 °C A

Shelf life

24 months

12 months

CQP = Corporate Quality Procedure

A) curing condition: 120 °C for 4 hours

Application

Surface preparation

The material, processing and mold or master-model temperature shall be between 18 °C and 25 °C.
Make sure the mold or master model is clean, dry, dust and grease free.
If mold or master-model surface is porous, it must be sealed prior applying the release agent. It is recommended to use wax-based release agents. For further information regarding Sika release agent consult the corresponding Product Data Sheet.

Application

Apply the gelcoat to the mold in a uniform thickness using a flat, short-haired brush. The material must be applied in a uniform direction to produce a homogeneous, gap-free surface layer.

 

The product shall be processed immediately after mixing. Direct pouring of the mixed product onto the mold surface may cause surface imperfections and adversely affect the surface quality of the cured material.
A coupling layer or other backfill layer shall be applied as close as possible to the tacky phase to ensure proper adhesion and prevent bonding issues. Tack-free time depends on application thickness, room and mold temperature.
Post-curing of the finished part at 120 °C for 4 hours improves the resistance of the gelcoat in respect of temperature, solvents and water.
Note: The post-curing requires a slow temperature increase and decrease process.
Depending on the geometry and weight of the part, it is recommended to use a counterpart (conformer) during post-curing.

STORAGE CONDITIONS

Both components must be stored at temperature between 15 °C and 25 °C in original unopened containers.