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Sikagard®-831

Interior and exterior intumescent coating for commercial vehicles

Sikagard®-831 is a solvent-free 2-pack modified epoxy-based intumescent fire-protection coating for internally or externally exposed aluminum or steel surfaces. It provides very high durability and combined corrosion and fire protection (EN45545 / NFPA 130). It is easily applied with standard airless spray equipment, requires no reinforcement, cures rapidly to a very tough and resistant finish ready for handling and transportation after 24 hours.  

  • High shock, impact and abrasion resistance
  • Application directly on sand blasted metal without primer
  • Wet film thickness = dry film thickness
  • Can be applied in one layer for up to 4 mm
  • Short coating and curing time (24 hours)
  • Halogen free
  • Meets EN 45545-2 R1/R7
 
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PRODUCT BENEFITS

  • High shock, impact and abrasion resistance
  • Application directly on sand blasted metal without primer
  • Wet film thickness = dry film thickness
  • Can be applied in one layer for up to 4 mm
  • Short coating and curing time (24 hours)
  • Halogen free
  • Meets EN 45545-2 R1/R7
 

Areas of Application

Sikagard®-831 is designed primarily for in-shop applications. It is typically used in the Transportation and Marine industry where it can be applied on internal and external aluminum, steel and GRP surfaces.
Sikagard®-831 is suitable for experienced professional users only. Tests with actual substrates and conditions have to be performed ensuring adhesion and material compatibility.  

Product Details

Typical Product Data
Chemical base

2-component modified epoxy

Color

Light grey

Cure mechanism

Polyaddition

Density

mixed

1.42 kg/l

Solid content (CQP002-2)

100 %

Mixing ratio

by weight

by volume

100 : 12

100 : 18.4

Application temperature

ambient, product and substrate

10 ─ 40 °C

Pot-life

at 20 °C

at 35 °C

30 minutes

15 minutes

Curing time

touch dry

hard dry (ready for handling and transport)

8 hours A

24 hours A

Compressive strength (ISO 604)

45 MPa

Bonding strength (Pull-off) (CQP057-3 / ISO 4624)

10 MPa

Tensile strength (CQP036-1 / 580-5,-6 / ISO 527-2)

10 MPa

Abrasion resistance (ISO 5470)

1000 g; disc: CS 10

65 mg/1000 R

Shelf life (CQP016-1)

24 months B

CQP = Corporate Quality Procedure

A) 23 °C / 50 % r. h.

B) storage below 25 °C

Application

Application Information

METHOD OF APPLICATION

Application by airless spray will give the best results and is recommended to achieve uniform thickness and appearance. In case of application by roller or brush, additional layers may become necessary to achieve the required coating thickness, depending on type of construction, site conditions, color shade etc.

Prior to the application it is recommended to perform a trial on site to ensure the selected application method will provide the requested results.

Sikagard®-831 is commonly applied by airless spray equipment - consisting in a single pump or a plural pump with a flow heater. A suitable setup could typically look as follows:

- Pressure ratio ≥ 66 : 1

- Air flow rate ≥ 24 l/min

- pressure at the spray gun ≥ 200 bar

- nozzle size: 0.019 ─ 0.025" (0.48 ─ 0.64 mm)

- spraying angle: 20 ─ 40°

The material temperature can reach up to 35 °C at the nozzle.

The filter mesh is not required and can be removed. Use direct material feed (without suction hose). At low temperatures it is recommended to use insulated spray hoses of a maximum length of 25 m.

Sikagard®-831 must not be diluted!

Surface preparation

Steel surfaces require a blast cleaning to Sa 2.5 according ISO 8501-1.

Aluminium surfaces require sweep blasting with a pure corundum, grain size e.g., F80, and reduced pressure (approx. 2.5 - 3 bar). To avoid oxidation of blasted surface, no more than 8 hours may elapse between sweep blasting and application of the Product.

Surface roughness after blasting can be assessed using a grit comparator as described in EN ISO 8503-1. For steel grade Sa 2.5, segment 2 to 3, 50 to 100 µm; for aluminium segment 1 to 3, 40 to 100  μm.

Other type of substrate must be tested individually. 

Surfaces must be clean and free from dirt, grease, oil and contaminants prior to application.

Application

Sikagard®-831 can be applied with ambient and surface temperatures between 10 °C and 40 °C. Optimum results are achieved at temperatures above 15 °C. If the product has been stored at lower temperature it is recommended to condition prior the application, for example by storing it close to the production line for up to 48 hours.

Relative humidity must not exceed 80 % and the ambient temperature has to be ≥ 3 °C above dew point.

If a second layer is required, the minimum waiting time is 8 hours at 20 °C. If the application and the storage is in a production facility (protected) the maximum open time is 7 days, in other cases it is reduced to 2 days.

Note: The previously applied layer must be dry and free from any dirt, moisture or contaminants that could compromise adhesion.

If waiting times are longer than indicated, the layer must treated by mechanical means, e.g. grinding, etc.

Temporary storage or transport of coated constructions must be carried out in a suitable manner. It is "good practice" that straps or chains are not brought into direct contact with the coated surface.

For repairs it is required to abrade coating areas to a matt finish and clean off dust. Use masking tape if necessary and then apply Sikagard®-831.

Removal

Clean the pump and tools immediately after use with Sika® Thinner E+B. Cured material can only be removed mechanically.

STORAGE CONDITIONS

Sikagard®-831 has to be kept between 5 °C and 30 °C in a dry place. Do not expose it to direct sunlight or frost. After opening of the packaging, the content has to be protected against humidity.