Wessex System 4401 moisture tolerant epoxy: Mixing, application and filleting


Both Part A and Part B should be stored in a warm, dry environment where a temperature of between 10-30°C can be maintained.

Please note: always keep containers closed and replace the protective polythene sheet when not in use to avoid skinning of the hardener component.

Surface preparation

Although Wessex System 4401 is tolerant of some contamination, best results are obtained on well prepared surfaces.

Ideally, surfaces should be mechanically abraded to provide the maximum mechanical key and be free from grease, moisture and dust particles. A solvent wipe will remove any contamination.

For emergency repairs when there is not time to prepare the surface, the effectiveness and durability of the putty bond may be impaired. Decisions regarding surface preparation must be taken on site dependent upon the individual situation. For advice, please contact us.


Mixing ratio: one part resin to one part hardener.

Mix the yellow filled epoxy resin component (Part A) with the blue hardener component (Part B). Blend thoroughly together. Mixing is complete when the adhesive turns green.

Small quantities of up to 500g can be mixed by rolling and kneading in the hands until a homogenous mix is obtained. For larger quantities we recommend that you use a mechanical mixer. A planetary action works well.

Please note: always wear gloves when handling our epoxies, and, as a further precaution, apply a suitable barrier cream to your hands if possible.


  1. Apply freshly mixed putty and work thoroughly into the surface to be built up.
  2. Spread as required to create the right thickness and shape, trapping as little air as possible.
  3. Do not subject to heavy stress until the final cure time has elapsed.
  4. It is possible to cut back the putty to the required shape or form using hand tools, providing this is done immediately after the material has hardened. If you don't do this straight away the putty will become extremely hard and it will be more difficult.


Filleting is a versatile technique for joining components when the parts are near or at right angles to each other. The continuous bead of putty applied to the angle between the two parts to be joined increases the surface area of the bond and serves as a structural brace.

Usable life

Once mixed, the usable life of a 500g batch is approximately 45 minutes at 20°C which allows ample working time for most purposes. When mixing larger quantities of putty the usable life becomes significantly shorter, so we advise that you break the putty into smaller quantities after mixing.


All synthetic resin materials should be treated with caution. Contact with the Wessex underwater epoxy products may result in dermatitis if care is not taken to avoid skin contact with the resins, the hardeners and the mixed materials.

Always wear gloves when handling our epoxies, and, as a further precaution, apply a suitable barrier cream to your hands if possible.

If any of the resin, hardener or mixed solution touches your skin, remove with a suitable cleansing cream, followed by thorough washing with soap and water.

Equipment care

Clean mixing equipment, tools and brushes with acetone or other ketones, or with a suitably blended solvent cleaner before the resin hardens. Once the resin has hardened, solvents are much less effective (please take suitable precautions for handling inflammable and volatile solvents).

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