Elastomeric polysulphide joint sealant

durakol® G HM is a gun grade two-component manganese cured high modulus polysulphide sealant.


durakol® G HM is used for sealing expansion joints, stress relief joints and movement joints in building and other civil engineering structures. These include superstructures, reservoirs and potable water retaining structures, floors, basements and subways.

Note: For sewerage treatment and waste water structures use flexothane G.

  • Suitable for use in potable water applications
  • Forms a tough, elastic, rubber-like seal
  • Accommodates continuous and pronounced cyclic movement in all planes
  • Excellent adhesion to most common construction materials
  • Specific primers ensure excellent adhesion to both porous and non-porous substrates
Joint Geometry

Minimum width of any joint is 6 mm. durakol® G HM may be applied in joints between 6 mm and 50 mm wide. The width of the joint should be four times that of the calculated joint movement. Joints that are expected to experience normal cyclic movements should be designed to an optimum width to depth ratio of 2:1, subject to the overriding recommended minimum sealant depths as follows:

  • 6 mm for metals, glass and other non porous surfaces.
  • 10 mm for all porous surfaces.
  • 20 mm for trafficable joints and those subject to hydrostatic pressures.

Joints expected to withstand hydrostatic or shear forces must have a width to depth ratio of 1:1.

The joint faces must be parallel.


Refer to the “Estimated Coverage Table” for both sealant and primer.

Surface Preparation

Thorough preparation of joints is essential if a satisfactory seal is to be obtained. For concrete surfaces, all traces of dust, laitance, mould oil, any previous sealant and all other foreign material must be removed by mechanical grinding, followed by blowing out with dry oil-free compressed air. All surfaces must be completely dry. Refer to “Preparation Of Surfaces” data sheet for further information.

Typical Physical Properties of Wet Material
Mixing ratio As supplied do not split kit
Density 1,74 g/cm3
Base Colour Off White
Activator Colour Black
Mixed Colour Grey
Dilution Do not dilute
Flash point None
Typical Physical Properties During Application
Application Method Extrusion gun
Pot life 2hrs / 25 °C
Slump resistance No slump in joint of 38 mm x 19 mm
Tack free 72 hours @ 25 °C
Full cure 7 days
Application temperature 5 °C to 35 °C
Fire resistance of wet film Non-flammable
Typical Physical Properties of Cured Material
Modulus@150% Extension 0.42N/mm2
Service temperature -5 °C to +80 °C
M.A.F. 25% of joint width
Shore A hardness 20 – 25
Chemical resistance Dilute acids and alkalis, fats and vegetable oils, petroleum fuels, oils, greases
Water resistance Excellent
Atmospheric oxidation Excellent
Protection of Adjacent Surfaces

Masking tape applied to areas adjacent to joints will protect them from smearing and enable the joints to be finished to a neat line. The masking tape should be applied after the joint has been prepared, prior to any priming or sealing operation and removed after all finishing and tooling operations have been completed, but before the sealant has cured.

Backing Material

Suitable back-up material, duracord, must be used to adjust sealant depth in the joint to comply with the joint geometry cited in the table. duracord is a self-releasing material, but if soft-board or cork is used as the joint filler, a plastic strip bond-breaker must be placed on the filler surface before sealant is applied.

Where hydrostatic pressure is expected, joint former should be minimum of 100kg/m3 density.

Bonding / Priming

Porous surfaces, such as concrete, stone, brickwork, timber and unglazed edges of ceramic tiles must be fully primed with epidermix® 326. Ensure primer is brushed well into the sides of the joint face, to ensure complete coverage. Avoid over-priming, this results in excessive primer in the base of the joint. The primer film should be allowed to lose its solvent (approximately 30 minutes drying) before sealant is applied. Primer open time is 4 hours. If, however, the primer is allowed to dry longer than 6 hours, the surface must be reground and re-primed.

Non-porous surfaces must be primed with epidermix® 391, brushed well into the faces of the joint to ensure complete coverage. The primer film should be allowed to lose its solvent (approximately 30 minutes drying) before sealant is applied.


durakol® G HM is supplied in a single container. The base is covered by a cellophane sheet. On top of the cellophane is a plastic container of activator paste. To prepare the material for use, remove the activator and cellophane sheet. Remove any base adhering to the cellophane and return to the container. Remove all the activator paste from its container and add to the base. Mix the material thoroughly, preferably with a slow-speed drill (not in excess of 250 r/min) fitted with a suitable paddle, until an even colour, free from streaks, is obtained. Periodically scrape the sides and base of the container with a spatula or small trowel to ensure complete blending of components. To obtain a complete mix will take approximately 5-10 minutes of mechanical mixing. If hand mixing is to be carried out, a minimum period of 15 minutes of vigorous mixing is required. Avoid air entrapment.

If the material is not mixed thoroughly, its performances will be impaired.


Application to primed surfaces can be by hand operated or pneumatic gun. It is essential to ensure complete contact between the sealant and the joint surfaces. Tooling of sealant is necessary for complete air-free filling of voids and to assist in making required surface contact by wetting the surfaces to which the sealant is applied. The surfaces of the joint should be smoothed with a clean knife or spatula, which may be moistened with a little clean water or water containing a little liquid soap. durakol® G HM should not be used in direct contact with materials containing pitch or bitumen. Do not use in bridge joints.

Sealant Coverage for Estimating Purposes
6 X 6 0.020 55
6 X 10 0.030 33
10 X 10 0.100 20
15 X 10 0.150 13
20 X 10 0.200 10
20 X 15 0.300 6.6
20 X 20 0.400 5
40 X 20 0.800 2.5
50 X 25 1.250 1.6
No allowance has been made in the above estimates for wastage
± 250 ml tin of epidermix® 326  per 3 tins/6 litres of sealant
± 500 ml tin of epidermix® 326  per 6 tins/12 litres of sealant
No allowance has been made for primer wastage or the varying porosity of the concrete to which it is applied.

All equipment should be cleaned immediately after use, and before the material has set, with abe® super brush cleaner followed by washing with soap and water.

Protection on Completion

The finished sealant should be protected from traffic until the sealant has fully cured. Over-painting of sealant is not recommended because of the inability of paint films to accept movement. However, if definitely required, trials should be carried out to determine compatibility.


durakol® G HM is supplied in 2 litre kits.

Handling & Storage

This product has a shelf life of 12 months if kept in a dry cool place in the original packaging. In more extreme conditions this period might be shortened.

Application Temperature

Surface and ambient temperature must be at least + 5 °C and rising ideally between 20 °C and 30 °C. Lower temperatures will extend the curing period. 

Model Specification

Two-component, gun grade, manganese cured, high modulus polysulphide sealant for use in water retaining structures. The sealant will be durakol® G HM, a two-component, high modulus polysulphide sealant applied in accordance with the recommendations of a.b.e.® including the use of epidermix® 391 and epidermix® 326 primers where required.

Health & Safety

Uncured durakol® G HM is toxic. Always ventilate the working area well during application and drying. Avoid flames in the vicinity of uncured durakol® G HM. Always wear gloves when working with the material and avoid excessive inhalation and skin contact. If material in splashed in the eyes, wash with copious quantities of clean water and seek medical attention.

Cured durakol® G HM is inert and harmless.

Important Note

This data sheet is issued as a guide to the use of the product(s) concerned. Whilst a.b.e.® endeavours to ensure that any advice, recommendation, specification or information is accurate and correct, the company cannot accept any liability for application – because a.b.e.® has no direct or continuous control over where and how a.b.e.® products are applied.

Further Information

Where other products are to be used in conjunction with this material, the relevant technical data sheets should be consulted to determine total requirements.

 a.b.e.®  has a wealth of technical and practical experience built up over the years in the company’s pursuit of excellence in building and construction technology.