Cutek Extreme - Penetrating Wood Oil for Decking and Siding by Cutek

Cutek Extreme is a deep-penetrating oil that stabilizes wood from the inside out to prevent warping, cupping, and splitting. It highlights the natural grain without ever peeling or flaking, ensuring your wood stays beautiful longer.

Maintenance is quick and simple with no sanding or stripping required. Apply it clear to let the wood silver naturally, or add a Colourtone to maintain a fresh look or change the wood's appearance to suit your style.

Deep-Penetrating Stability: Penetrates deep into the grain to minimize warping, cupping, and splitting.
No Peeling or Flaking: A high-performance stabilizer that highlights natural beauty without surface failure.
Simple Maintenance: Quick and easy upkeep with no need for sanding or stripping.
Extreme Weather Resistance: Proven to withstand harsh climates and high UV exposure.
Customizable Look: Use it clear for a natural silvering effect or mix with a Colourtone to maintain or alter the color.

Colors shown are for information purposes only: Actual colors may vary from the color on your screen due to monitor differences.

Documents

Technical Data Sheet Safety Data Sheet Brochure

Directions for Use

STEP 1: PREPARATION

To ensure Cutek Extreme performs effectively, it must be able to diffuse deeply into the wood fibers. Any barriers to penetration—such as existing non-Cutek coatings, trapped moisture, or insufficient drying time—must be resolved before application.

Cutek Extreme should only be applied to wood that is clean, dry, and free of grease. The moisture content must be below 17%. Proper preparation is essential for a successful finish.

New Wood

Wood must be bare, clean, and dry. If the surface shows contaminants like water marks, iron stains, tannins, or mill glaze, we recommend using Cutek Wood Reviver before applying Cutek Extreme.

Old, Greyed, or Weathered Uncoated Wood

Aged, dirty, or greyed wood should be restored using Cutek Wood Reviver. This process removes the silvering and restores the wood's original color and grain before you apply Cutek Extreme.

Wood Previously Coated with Non-Cutek Products

Cutek Extreme requires bare wood for proper diffusion. Previous film-forming coatings—such as stains, linseed oil, paint, polyurethane, or water-based oils—will block penetration and must be removed. Use Cutek Wood Stripper followed by Cutek Wood Reviver, or perform a deep mechanical sanding to reach bare wood.

Wood Previously Coated with Cutek Extreme

For routine maintenance, use Cutek Quickclean to remove grease and surface grime. If maintenance has been neglected and the wood has greyed, become heavily stained, or has an excessive build-up of Cutek Colourtone, use Cutek Wood Reviver to refresh the substrate before recoating.

Determining Suitability

To confirm if Cutek Extreme is right for your specific project, we recommend testing a pre-mixed sample available from our retailers or contacting us for professional advice.

STEP 2: PROTECT

Before You Begin

Prior to application, review all hazards and precautions listed on our website and product labeling. Ensure you are using the appropriate safety equipment as specified in the Safety Data Sheet (SDS).

Weather Considerations

Cutek Extreme typically requires 3 to 5 days of warm, dry, and sunny weather after application to allow for full penetration and an even finish. Always check the weather forecast before you start coating.

Cutek Colourtone

Applying Cutek Extreme "Clear" (untinted) will protect the wood while allowing it to naturally lighten or silver when exposed to UV rays. To maintain a "freshly oiled" look or to change the color, you must mix one bottle of Cutek Colourtone per 3.6L (0.95 US gal) of Cutek Extreme. Adding a Colourtone provides critical UV protection and significantly slows the silvering process.

Note: Even without Colourtone, Cutek Extreme diffuses deeply to provide moisture protection and structural stability.

Application Process

Wood must be completely clean, grease-free, and dry, with a moisture content below 17%. The surface must also be free of chemical residues and protected from dust during the drying phase.

Stir Well: Stir the oil thoroughly from the bottom of the can before and during use to ensure active ingredients and pigments are evenly distributed.
Apply Thinly: Use a brush or paint pad to apply thin, even coats. Two or three thin coats are far more effective than one thick coat.
Pre-Installation: For best results, apply one coat to all faces of the wood before installation, followed by a second coat on the top surface once the first has fully diffused.
Post-Installation: Apply two thin coats to all accessible surfaces, ensuring the first coat is completely dry before applying the second.

Drying and Diffusion

Cutek Extreme does not dry like traditional paint; it migrates deep into the wood. This process varies based on wood species, density, porosity, and environmental conditions.

The Tissue Test: To check if the wood is ready for a second coat, press a tissue or rag against the surface. If there is no oil transfer, it is dry. Note that the second coat will take longer to diffuse than the first.

Clean Up and Safety

Clean equipment with Cutek Quickclean, mineral spirits, or soap and water.
WARNING: Oily rags can spontaneously combust. You MUST immediately spread oily materials flat outdoors in an airy spot (above 4°C / 39°F) to dry completely, or wash them thoroughly with detergent and water before disposal.

Coverage Guidelines (Estimates Only)

New hardwoods (dressed/smooth): 10–20 m²/L (400-800 ft²/gal)
Old restored wood (dressed/smooth): 6–8.5 m²/L (250-350 ft²/gal)
New wood (rough sawn): 6–7.5 m²/L (250-300 ft²/gal)
Old restored wood (rough sawn): 3.5–6 m²/L (150-250 ft²/gal)
Shingles and shakes: 2–5 m²/L (84-212 ft²/gal)

MAINTENANCE

Maintenance with Cutek Extreme is simple, fast, and cost-effective. Because Cutek Extreme does not crack, peel, or split, your wood can be easily rejuvenated or restored using our "Prepare and Protect" system without ever needing to sand or strip the surface.

When to Reapply

Cutek Extreme should be reapplied when the wood no longer causes water to bead, or as frequently as desired to maintain the wood's natural beauty and specific color.

The Cumulative Effect

Due to the cumulative nature of Cutek Extreme, each subsequent maintenance coat typically requires less oil than the previous one. As the protective properties build up within the wood fibers, the intervals between required recoats will naturally extend.

Variation by Surface Type

Exposure levels dictate maintenance frequency:
Horizontal surfaces: Decks, pool surrounds, and handrails exposed to full weather usually require more frequent care (initially every 6–12 months).
Vertical surfaces: Cladding or siding, especially if rough-sawn, typically requires maintenance much less often.

Cutek Extreme: Superior Penetration and Self-Healing Protection

Unlike traditional wood stains, acrylics, or natural oils (like linseed or tung oil), Cutek Extreme protects your wood from the inside out. Instead of drying into a hard surface film, Cutek Extreme remains permanently mobile within the wood.

How the "Self-Healing" Effect Works:

Deep Diffusion: Upon application, the oil penetrates deep into the wood core, protecting it from moisture in both liquid and gas forms.
Active Migration: Because it never "dries" to a solid, the oil continues to migrate throughout the wood fibers.
Self-Healing Action: If the wood is cut or perforated by fasteners, the mobile oil moves to the new opening to seal and protect it automatically.

Why Traditional Coatings Fail:

Many "penetrating" oils only reach a few millimeters before drying into a varnish-like shell. Once this surface is punctured or weathered, water can reach the wood core, leading to warping and rot. Furthermore, some natural oils can actually promote the growth of unsightly mould and fungi beneath the surface—a problem that is both difficult and expensive to fix.

NOTE: Any coating that is not permanently mobile and does not offer a self-healing effect is simply not the same as Cutek Extreme, regardless of marketing claims.

Variants

3.6 L · Clear (No tint)	$139.99	In stock
18.9 L · Clear (No tint)	$434.99	Out of stock

Specifications

Classification	Oils & Oil Finishes for Wood
Brand	Cutek
Sizes	3.6 L 18.9 L
Sold Since	April 11, 2026
Composition	Distillates, petroleum, hydrotreated light paraffinic, Naphtha, petroleum, hydrotreated heavy, Oxirane, mono[(C12-14-alkyloxy)methyl] derivatives, Paraffin waxes and Hydrocarbon waxes, 3-Iodo-2-propynyl butylcarbamate
Coverage	Coverage Guidelines (Estimates Only) New hardwoods (dressed/smooth): 10–20 m²/L (400-800 ft²/gal) Old restored wood (dressed/smooth): 6–8.5 m²/L (250-350 ft²/gal) New wood (rough sawn): 6–7.5 m²/L (250-300 ft²/gal) Old restored wood (rough sawn): 3.5–6 m²/L (150-250 ft²/gal) Shingles and shakes: 2–5 m²/L (84-212 ft²/gal)
VOCs	≈215g/L (1.79lb/gal) ASTM 3960
Dilution	Do not thin
Viscosity	≈24cSt

FAQ

Are Cutek oils safe for playgrounds and play equipment?

Yes. Cutek oils are safe and effective for timber playgrounds and play equipment.
As a penetrative oil, once the Cutek has fully penetrated into the timber, it is unlikely to leave residue when touched or brushed against.

How long can I store Cutek Extreme for?

Cutek oils can be stored for one year or more and reused for the next coating season, when stored correctly. To store correctly, store in a cool, dry area out of direct sunlight; lid must be airtight. If the lid has been damaged, the remaining contents may be tipped into another compatible container (HDPE or Lined metal containers). Minimising the air space in the can will also increase the storage life of the product.

If the oil has been tinted with a Cutek Colourtone, the colour may settle out and be difficult to stir in again if some time has passed. Use caution when mixing new and old Cutek Oils that have been coloured with a Cutek Colourtone; there may be some discrepancies in colour due to storage.

How long can I store Cutek Colortounes for?

After use, Cutek Colourtones generally do not require storing because they are a one-use product. If the Colourtone can contents have solidified, do not use the Colourtone. Instead, dispose of the can and contents according to local regulations.

What should be avoided when planning to coat wood with Cutek Extreme?

Wet wood, or wood with a high moisture content: Your wood should contain a maximum moisture content of 17%, as anything higher can significantly delay the drying process. If the moisture content is above 17%, Cutek Extreme may sit on the surface and eventually go tacky without penetrating properly.
Too many coats too soon: The first application of Cutek Extreme needs to completely diffuse and dry before the next coat is applied.
Existing oil, stain or paint on the surface of your wood: Existing film coatings act as a barrier to Cutek Extreme‘s penetration. Old coatings must be fully removed by sanding and/or chemical stripping prior to applying Cutek Extreme.
Cold weather: Cutek Extreme should not be applied below 10° C (50° F). In cold weather Cutek Extreme will become thicker and may result in too much oil being applied. When applying in cooler climates, keep the oil in a warm spot until ready to apply to make it thinner and enhance penetration.
Contamination: It is very important to ensure that wood surfaces to be coated with Cutek Extreme are free from chemical residues and are not exposed to environmental contaminants such as dusts while the applied oil is drying. It is possible that contact with highly alkaline contaminants such as cement/fertilizer/other dusts or poorly rinsed cleaners may lead to chemical staining.

What is the average coverage rate when using Cutek Extreme?

Cutek Extreme‘s coverage will be different depending on the density and condition of the wood you are intending to coat. Please see below for a guide on the coverage rate of different wood substrates:

What is the average coverage rate when using Cutek Extreme?

Cutek Extreme’s coverage varies depending on the density and condition of the wood. Use the following guide for different wood substrates:

New wood (sanded): 10–20 m²/L (400–800 ft²/gal)
Old restored wood (sanded): 6–8.5 m²/L (250–350 ft²/gal)
New wood (rough sawn): 6–7.5 m²/L (250–300 ft²/gal)
Old restored wood (rough sawn): 3.5–6 m²/L (150–250 ft²/gal)
Shingles and shakes: 2–5 m²/L (84–212 ft²/gal)

NOTE: These figures represent typical averages for common decking and cladding wood species and are to be used as a guideline only.

Can I apply Cutek Extreme without sanding between coats?

Cutek Extreme does not behave like traditional film forming coatings, meaning there is no need to sand between coats, unless there is a need to fix some defect in the wood substrate.

Can I apply Cutek Extreme on hot sunny days?

Yes. Unlike many wood coatings, Cutek Extreme performs well in dry, hot conditions. In fact, heat and ventilation greatly assist the deep diffusion of Cutek Extreme into the wood.

Why do I have to wait between coats?

Cutek Extreme must be allowed to diffuse into the wood and fully cure between coats. If it is not fully dried, and another coat is applied the drying time of the second coat may be extended for much longer than it needs to be.

The speed of the drying process varies according to many different factors such as wood species, density, porosity, residual moisture content and temperature. Pre-coated wood will always dry faster if stacked outside.

How long does it take for Cutek Extreme to dry?

Unlike traditional wood coatings, Cutek Extreme needs to penetrate/diffuse deeply into your wood. After coating, Cutek Extreme will slowly migrate into your wood to repel and displace moisture, improve dimensional stability and lengthen the service life of your wood. This penetration/diffusion process varies in time for many reasons including differences in wood type (species, density, porosity, age of wood and residual moisture content) as well as environmental factors (temperature, humidity, weather). Sometimes this drying process can take several days to complete. You will know when your wood is ready for an additional coat of Cutek Extreme when it is completely dry and non-greasy. Please note the second coat of Cutek Extreme will take longer to migrate into your wood than the first coat.

Pre-coated wood will always dry faster if stacked outside.

I have just applied Cutek Extreme and it is taking a long time to dry. Why is this?

Cutek Extreme works by deeply diffusing into the wood and it won’t dry on the surface until this process has been fully completed. The drying process varies in time according to many different factors such as wood species, density, porosity, residual moisture content and temperature, humidity etc.

To help ensure your Cutek Extreme dries as quickly as possible, make sure you avoid:

Wet wood, or wood with a high moisture content. Your wood should contain a maximum moisture content of 17%, as anything higher can significantly delay the drying process. If this happens, Cutek Extreme may sit on the surface and eventually go tacky without penetrating properly.

Cold weather. You should not apply Cutek Extreme if it is below 5°C (40°F). In cold weather Cutek Extreme will become thicker and therefore too much oil is applied. Keep oil warm before application to make it thinner and to enhance penetration. Thin coats are recommended.

Too many coats too soon. The first application of Cutek Extreme needs to completely diffuse and dry fully before the next coat is applied.

Existing oil, stain or paint on the surface. Existing film coats act as a barrier to Cutek Extreme‘s penetration. Old coatings must be fully removed by sanding and/or chemical stripping prior to applying Cutek Extreme.

For best results, always allow Cutek Extreme to completely diffuse before adding an additional coat or using. If you cannot wait, rag off the excess material on the surface and the coating will dry on top at a much faster rate.

What do I use to clean up a Cutek Extreme spill?

Time is of the essence. For best results clean up the excess oil with rags and then work the stain with a Cutek Quickclean and water mixture to remove as much of the spill as possible. If Cutek Quickclean is not available, then mix dishwashing liquid into warm water with some mineral spirts or turpentine, if possible, and work the stain with this mixture.