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TWA Clear Water Repellant


TWA CLEAR WATER REPELLANT is an oil based penetrating coating for timber. It protects the effects of rain and sun based weathering in exterior applications. Timber protected with TWA CLEAR WATER REPELLANT will have an improved resistance to warping, splitting, cracking, and weathering, therefore maintaining the beauty and serviceability of exterior timber structures such as decks, furniture, cladding, lattice and pergolas. It is specially formulated for use with CCA, Tanalith-E, ACQ and LOSP treated timber. It can also be used with normal untreated timbers such as Merbau, Cypress, and Jarrah in exterior applications. Once dry, timber treated with TWA CLEAR WATER REPELLANT is safe to use in outdoor situations. TWA CLEAR WATER REPELLANT is generally recommended for exterior use only.

This product should not be used as a preservative finish on weather exposed, non durable untreated timbers such as Oregon or Radiata Pine.


TWA CLEAR WATER REPELLANT penetrates deeply to form a water repellant envelope around the timber. This envelope repels water and maintains a lower and more stable moisture content in the timber. Since fluctuation of moisture content is the main cause of dimensional instability it will greatly reduce splitting, warping and checking. Ultra violet light present in sunlight interacts directly with the cellulose and lignin polymers in timber. The polymer chains are broken down and in combination with other forms of weathering will form a rough and powdery surface. The colour of the timber will be degraded. TWA CLEAR WATER REPELLANT will not prevent some bleaching but it will prevent the surface erosion and roughening. The grey stains and spots that occur on timber are mainly due to moulds. Moulds do not do significant physical damage to timber but the stains are unsightly and can be very difficult to remove.


TWA CLEAR WATER REPELLANT may be used as a sealant and foundation for other surface coatings. It is directly compatible with other alkyd or oil based paints and stains. However as it is water repellant, some problems may be encountered when using acrylic or water based products as a top coat. If this type of product is required first coat over the TWA CLEAR WATER REPELLANT with an oil based primer. In all cases where overcoating with another product is required: Use only one coat of TWA CLEAR WATER REPELLANT. Allow to dry for at least three days. Check for adhesion first in an inconspicuous place. When used as directed, it will improve the performance of other surface coatings. As other surface coatings will impede or prevent penetration, it is not recommended to apply TWA CLEAR WATER REPELLANT over other products such as acrylics or estapols.


  • Density: 0.83kg/L at 20oC
  • Flash Point: >64oC
  • Odour: Mild Petroleum
  • Viscosity: 25cp



TWA CLEAR WATER REPELLANT is intended to protect and enhance the beauty of any exterior timber surface. It is suitable for decking, fencing, cladding, furniture, lattice, windows, pergolas and any other similar timber surface. It is the ideal complement for CCA, Tanalith-E, ACQ & LOSP treated timbers.

Many hardwoods particularly when new may be difficult for the TWA CLEAR WATER REPELLANT to penetrate, this may cause drying and surface problems. In these cases it is recommended to allow the timber to season for a period of 3-6 months until satisfactory penetration and drying can occur. An alternative is to apply a diluted solution of TWA CLEAR WATER REPELLANT (50:50% Mineral Turps), wipe off any excess after 24 hours, leave for 3-6 months and then apply another full strength coat of CLEAR WATER REPELLANT . Always test brush in a small area or on off-cuts before doing the full area.

Product Preparation

Mix thoroughly before use to ensure solids and pigments are evenly distributed. Pigment may be settled and compacted after extended shelf storage. Thinning is not normally required. However, if the product does not readily absorb, (to new dressed timber, hardwoods or during cold weather), thinning with mineral turps may assist penetration. Normally 1 or 2 parts of turps to 10 parts of product will be sufficient. The total number of coats may need to be adjusted to achieve the desired properties.

Surface Preparation

New timber should be dry and free from dirt, sawdust etc. Old or weathered timber should be treated with TWA WOODBRITE prior to CLEAR WATER REPELLANT for best results. Even new timber that is watermarked and dirty will benefit from a treatment with TWA WOODBRITE. (Please ensure that the timber has thoroughly dried after this). In order to work properly CLEAR WATER REPELLANT must penetrate, therefore the timber surface should be reasonably dry before application. A drop of water should absorb readily. If not, the timber is not dry enough and should be left for a few more days. (this step is irrelevant for additional coats.)


TWA CLEAR WATER REPELLANT can be applied by brush, roller or dip methods. (Ensure adequate ventilation during use and avoid a proximity to heat sources or open flame.) Dipping application may require back brushing for an even appearance. Do not use the product if rain is expected
within 24 hours of application. Work it into the timber grain with only a moderately full brush. To get maximum penetration and benefit DO NOT apply CLEAR WATER REPELLANT in direct sunlight or onto a hot surface. Similarly do not apply in very cold weather (>15oC) or very hot weather – above 25oC. Decant into small containers for use rather than leave the main container open for long periods. Stir occasionally during use. Coverage will depend greatly on the timber type and its condition but will generally be in the range of 4 to 8 square metres per litre. Coverage will improve with second and third coats. The surface will be touch dry after 2 hours, however leave for 24 hours between coats and before use. If possible with new timber wait for one week before applying additional coats. Clean up with mineral turpentine or paint thinner.

Result of Application

TWA CLEAR WATER REPELLANT will enhance the grain and colour and may darken some timbers (eg Western Red Cedar). On treated pine in particular the effect will be a warmer golden hue that may darken with exposure.

Recommendations and Re-Application

Two coats at least should be applied to exterior timbers. For best protection and results all surfaces (including underside of decks), should be coated before joining and after cutting or machining. Obviously this will not be possible in many cases. However where possible give special attention to endgrain joints and interfaces.


Preschem provides free technical advisory service on all aspects of timber preservation including the use of this product. Call us Toll Free now on 1800 641 711.

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