Advise - Dosing and mixing WEST SYSTEM products

Careful measuring of resin and hardener and thorough mixing of the two components are essential for a proper cure. Whether the resin/hardener mix is applied as a coating or modified with fillers, observing the following procedures will ensure a controlled and torough chemical transition to a high strength epoxy solid.


Dispense the correct proportions of resin and hardener into a clean plastic, metal or wax-free paper container (see picture). Do not use glass or foam containers because of the potential hazard from exothermic heat build-up. Do not attempt to adjust the cure time by altering the mix ratio. An accurate ratio is essential for a proper cure and full development of physical properties.

Dispensing with pump:

Most problems related to the curing of epoxy can be traced to the wrong ratio of resin and hardener. To simplify metering, use calibrated WEST SYSTEM pumps to dispense the correct working ratio of resin and hardener. (for one full pump stroke of resin use one full pump stroke of hardener).

Depress each pump head fully and allow the head to retrun completely before the beginning the next stroke. Partial strokes wil give an incorrect ratio. Read the pump instructions before using the pumps and verify the correct ratio before using the first mix on a project. Recheck the ratio whenever curing problems are experienced. One full depression of each pump will give approximately 24g of mixed epoxy.

One full pump stroke of resin for one full pump stroke of hardener will give the correct ratio
Dispensing without pumps: weight/volume measure:

To measure 105 resin and 205 or 206 hardener by weight, combine five parts resin with one part hardener. Small quantities can be lixed by volume at the same ratio. To measure 105 resin and 207 or 209 hardener by volume, combine three parts resin with one part hardener (by weight: 3.5 parts resin 1 part hardener)

First time users

If using WEST SYSTEM epoxy for the first time, begin with a small test batch to get the feel for the mixing and curing process before applying a mix to the job in hand. This will demonstrate the open time for the resin/hardener mix at the present ambient temperature and  give assurance that the mix ratio is correctly metered. Mix small batches until confident of the handing characteristics of the epoxy.


Thoroughly blend the two ingredients for two minutes - longer in cooler temperatures. Scrape the sides and bottom of the pot when mixing. If using the mix for coating, after mixing quickly pour into a roller pan to extend the open time.

Curing epoxy generates heat. Do not fill or cast layers of epoxy thicker than 10 to 12mm - thinner if enclosed by foam or insulating material. If left to stand for the full pot life in a plastic mixing epoxy begins to exotherm (heat up), quickly move it outdoors. Avoid breathing the fumes. Do not dispose of the mixture until the reaction is complete and the material has cooled.

Adding fillers:

After selecting an appropriate filler for the job in hand, use it to modify the property of epoxy mixing.

Blend in small quantities of the appropriate filler until the desired consistency is reached. Ensure the filler is thoroughly blended before the mix is applied.

Surface preparation:

Before apply the epoxy mixing, clean the surface with acetone, let it dry and sand surface.

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