Wessex System 325: Mixing, application and storage
Because epoxy systems are exothermic, it is important to appreciate that the temperature of both the environment and the two components before mixing, together with the total mass of the epoxy, determines both the working and gelation of time of the adhesive.
Therefore, we recommend storing Wessex System 310 at temperatures above 15°C. To shorten the period between the application of the adhesive and the subsequent trafficking of the tiled area, the material should be held at higher temperatures up to, say 25°C. Even under these storage conditions both resin and hardener exhibit excellent anti-settling properties.
It is vital that the epoxide resin and hardener are well mixed to produce a homogenous blend – an essential requirement for ultimate bond strength. With heavily filled systems such as the Wessex System 325 epoxy, complete mixing is even more important.
With the Wessex System 325 pack, pour the total contents of the polybucket containing the epoxide resin into the epoxide hardener and mix thoroughly for four minutes.
The larger the pack size, the more difficult and time-consuming the mixing operation becomes. The volume of the pack is blended into a homogenous mass by mixing for a minimum of four minutes with an air-driven mixer, ideally fitted with a large gate paddle.
When mixing is complete the adhesive will form a uniform colour and all signs of streakiness will have disappeared.
Within ten minutes of mixing the epoxy composition, it must be applied to the substrates.
Rough surfaces, such as a concrete floor, must be completely wetted and a thin coating spread onto the floor covering and the concrete floor to which it is to be bonded. In practice, it has been found when working with smooth, new surfaces, i.e. wood and metal, that only the base floors need to be coated.
A screeding tool such as a saw tooth scraper has been found to be the most suitable for applying the adhesive to a thickness of approximately 0.3mm - this will give a coverage of about 0.3kg/m² - and to obtain this thickness of coating, the scraper has a serrated edge having a minimum depth of 0.5mm.
Immediately after application onto the substrates, the mixed epoxy will flow to the required uniform thickness and the floor covering can be positioned onto the floor. To ensure that intimate contact is maintained between the floor covering and the floor throughout the curing cycle, some weight should be placed onto the covering.
Synthetic resins can cause dermatitis if not handled properly, so care should be taken to avoid contact with the skin. Before working with these materials the relevant Material Safety Data Sheets must be read:
Wessex System 310 Epoxide Resin Part A
Wessex System 310 Epoxide Hardener Part B
Application of Wessex Barrier Cream to the hands affords protection against contact with the synthetic resin and hardener.
After finishing work with Wessex System 310, wash your hands with Wessex Resin Removing Cream, followed by soap and water. Solvents must not be used.
Mixing equipment and tools should be cleaned with a suitable solvent before the adhesive has cured, such as WEST SYSTEM 850 Solvent or acetone.
These materials are flammable and must be handled with care, and away from any flames or sources of ignition.
It is important that these solvents are not used for cleaning the skin as this can cause defatting. Solvents are ineffective against cured epoxide resins unless totally immersed for a very long period, when the resin will soften.