One resin system for bonding, coating and laminating
WEST SYSTEM 105 is a clear, low-viscosity, solvent-free liquid epoxy that cures with WEST SYSTEM hardeners over a broad temperature range. It wets out fibers, penetrates timber and self-levels when roller-applied. Modified with WEST SYSTEM fillers, it becomes a gap-filling adhesive, fairing compound or structural putty; once cured it can be shaped, drilled or sanded.
Applications
- Boat building and repair
- Bonding and coating timber, furniture
- Fiberglass, reinforcing fabric and composite laminates
- Structural bonding to metals and other substrates
- Gap filling and fairing with fillers
Choosing a hardener
- 205 Fast – medium-viscosity general-purpose hardener that cures down to 10°C.
- 206 Slow – low-viscosity hardener for longer working and cure times.
- 207 Special Coating – for clear, moisture-resistant natural wood finishes. Contains a UV inhibitor, but a UV-filtered varnish or polyurethane is still needed.
- 209 Extra Slow – for hot or humid conditions or extended working time. Not for clear coating.
Liquid properties
| 105 Resin | 205 | 206 | 207 | 209 | |
|---|---|---|---|---|---|
| Viscosity, mPa·s @ 25°C | 550 | 500 | 160 | 200 | 130 |
| Specific gravity, g/ml @ 25°C | 1.15 | 1.04 | 1.00 | 1.00 | 0.98 |
Mix ratio and cure (105 + hardener)
| 205 Fast | 206 Slow | 207 Special Coating | 209 Extra Slow | |
|---|---|---|---|---|
| Mix ratio by volume (105 : hardener) | 5 : 1 | 5 : 1 | 3 : 1 | 3 : 1 |
| Mix ratio by weight | 5 : 1 | 5 : 1 | 3.5 : 1 | 3.5 : 1 |
| Pot life – 100 g @ 25°C | 9 min | 20 min | 24 min | 37 min |
| Thin-film cure @ 25°C | 12 h | 17 h | 21 h | 25 h |
| Min. recommended temperature | 10°C | 16°C | 16°C | 21°C |
| Mixed viscosity, mPa·s @ 25°C | 560 | 580 | 560 | 540 |
| Shore D, 1 day | 75 | 77 | 74 | 75 |
| HDT after 2 weeks @ 25°C | 46°C | 47°C | 44°C | 46°C |
Do not change the mix ratio to adjust cure time – choose a different hardener instead.
Cured casting properties
| 205 Fast | 206 Slow | 207 Special Coating | 209 Extra Slow | |
|---|---|---|---|---|
| Tensile strength (ASTM D638) | 54.1 MPa | 50.5 MPa | 51.7 MPa | 50.1 MPa |
| Tensile elongation | 3.4% | 4.5% | 3.4% | 3.6% |
| Tensile modulus | 2,813 MPa | 3,172 MPa | 2,827 MPa | 2,744 MPa |
| Flexural strength (ASTM D790) | 97.3 MPa | 81.4 MPa | 89.7 MPa | 85.9 MPa |
| Flexural modulus | 3,178 MPa | 3,103 MPa | 3,544 MPa | 2,737 MPa |
Storage
Shelf life 2 years in original, tightly sealed containers. Store at 15–32°C away from direct sunlight to limit moisture absorption.
Safety
Moderate skin-sensitizing potential. Avoid skin and eye contact; work with good ventilation, impervious gloves and safety glasses. Refer to the SDS for full information.
Frequently asked questions
What is the WEST SYSTEM 105 mix ratio?
With 205 or 206 hardener: 5 : 1 by volume (5 : 1 by weight). With 207 or 209: 3 : 1 by volume (3.5 : 1 by weight).
Which hardener should I choose?
205 for fast work and low temperatures (down to 10°C); 206 for longer working time; 207 for clear wood coating; 209 for hot, humid conditions or the longest working time.
What is the pot life of 105?
For a 100 g mass at 25°C: 205 about 9 min, 206 about 20 min, 207 about 24 min, 209 about 37 min.
Can 105 be used as an adhesive or fairing compound?
Yes. Modified with WEST SYSTEM fillers, 105 becomes a gap-filling adhesive, fairing compound or structural putty.
Which substrates is 105 for?
Wood, fiberglass, reinforcing fabrics, composites and metals.
How should 105 be stored?
In original, tightly sealed containers at 15–32°C, away from sunlight. Shelf life is 2 years.
Current documents are provided by GKFRP upon request for the correct product grade and application.
Mechanical properties are for neat cast resin; actual results depend on hardener, temperature and cure schedule.