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West System 105 RESIN

Epoxy Resin & Hardeners

WEST SYSTEM 105 Epoxy Resin and Hardeners make up a versatile epoxy system that can be used for everything from basic, long-lasting repairs to the construction of high-performance composites.

When blended at the appropriate mix ratio, WEST SYSTEM Epoxy Resin and Hardeners will cure to a high-strength plastic solid at 72°F. The resulting plastic adheres tenaciously to a wide range of materials including woods, fiberglass and other reinforcing materials, and metals. Select from a range of hardeners and additives to tailor your epoxy mixture’s handling characteristics and cured physical properties to suit your working conditions and specific coating or bonding application.

Group Size Packaging

WEST SYSTEM Epoxy resin and hardeners are packaged in three “Group Sizes.” For each container size of resin, there is a corresponding sized container of hardener. When purchasing epoxy resin and hardeners, be sure both containers are labeled with the same group size letter: A, B, C, or E.

Storage and Shelf Life Resin and Hardeners

Store epoxy resin and hardeners at room temperature. Keep containers closed to prevent contamination. With proper storage, epoxy resin and hardeners should remain usable for many years. After a long period of storage, verify the metering accuracy of your epoxy pumps. Mix a small batch of epoxy (3 pumps strokes of resin and 3 pump strokes of hardener), stir thoroughly for one full minute and leave in the mixing cup. The epoxy should cure to a solid within the time frame listed on the hardener can for the temperature of your working environment. This lets you know that your epoxy resin and hardener has not become contaminated and should be suitable for use on your project.

Over time, 105 Epoxy Resin will thicken slightly so will require extra care when mixing. Repeated freeze/thaw cycles during storage may cause crystallization of 105 Resin. If this occurs, simply warm the resin can to 125°F and stir to dissolve the crystals.

Hardeners may darken with age, but cured physical properties are not affected by color. If clear finishing, be aware of a possible color shift if you plan to use very old and new hardeners on the same project.

Dispensing and Mixing Epoxy Resin and Hardener

It is critical that you dispense epoxy resin and hardener at the correct ratio. Altering the amount of hardener does not control cure speed. Instead, it creates an epoxy mixture that can never fully cure and will have greatly reduced physical properties.

Epoxy can be accurately metered by volume or weight. Mix ratio information is on the hardener label and our technical data sheets.

Our 300 Mini Pumps are hard to beat for the price when metering small amounts of epoxy. One full pump stroke resin to one full pump stroke of hardener delivers the correct ratio. One pump stroke of each will total around 1 fluid ounce of epoxy. Depress each pump head fully then allow it to rise to the top before beginning the next stroke.

To measure resin and hardener by volume, pour each component into a straight-sided container like our 805 or 806 Mixing Pot.

Another method for metering by volume in a straight-sided container is to mark a paint stick at 5 parts 105 Resin and 1 part 205 Fast or 206 Slow Hardener. For example, put a mark at 1.25″ for the resin, then another 0.25″ above that, put a mark for the hardener, for a total of 1.5″. Pour the resin into a straight-sided container to the 1.25″ mark, then add hardener to the 1.5″ mark. This can also be done for 207 Special Clear and 209 Extra Slow Hardener but at 3 parts resin to 1 part hardener.

When mixing, stir the epoxy for at least two minutes to ensure it is thoroughly blended. In cooler temperatures, you will need to mix the epoxy longer. Scrape the sides, bottom, and inside corners of the container when mixing to ensure thorough blending.