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Würth Painter's Acrylic Filler

Würth Painter's Acrylic Filler

Elastic acrylic sealant for window sealing and interior expansion joints; paintable and plaster-compatible with low emissions.

08921611

In stock

⚙ Ideal For

  • Interior window sealing
  • Expansion joints indoors
  • Outdoor expansion joints
  • Paint and plaster finishing
  • Low-emission applications

✔ Benefits

  • Highly elastic formula
  • Paintable and plaster-compatible
  • Broad substrate adhesion
  • UV and weathering resistant
  • Silicone-free and odourless

Expansion joints in buildings require sealants that accommodate movement without cracking. Standard rigid fillers fail to flex with structural movement, leading to joint failure and water ingress. Sealants that do not bond reliably to common building surfaces require additional primers and pre-treatment, increasing labour time and material costs.

Würth Painter's Acrylic Filler addresses this by providing a highly elastic acrylic sealant with excellent adhesion to standard construction surfaces. The formula accepts both paint and plaster finishes, allowing seamless integration into interior and exterior decoration schemes.

Key Features

  • Highly elastic formula — Remains flexible after curing to accommodate building movement and thermal expansion without cracking; movement absorption capacity of 20%.
  • Broad substrate adhesion — Bonds reliably to a variety of standard construction surfaces without primer on most substrates; primer recommended for absorbent or porous surfaces.
  • Paintable and plaster-compatible — Accepts both paint and plaster finishes for seamless integration into interior and exterior decoration schemes.
  • UV and weathering resistant — Resistant to ageing, weathering, and UV exposure; suitable for both indoor and outdoor expansion joints.
  • Low-emission formula — EMICODE EC1plus certified; silicone-free and odourless, making it safe for use in occupied spaces and low-VOC environments.
DETAILED DESCRIPTION →
£9.99 GBP
£9.99 GBP
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Taxes included. Shipping calculated at checkout.

Shipping Information

What Are My Shipping Options?

In-Store Pickup

In-Store pickup is available on all purchase. Pickups are available Monday - Friday between the hours of 9:00–17:00. 

An email confirmation will be sent when your order is ready for collection. 

Free Shipping

We offer free Standard (2-3 Days) shipping on orders within the United Kingdom on orders over £100. Please note, some large items that require specialist courier companies, such as large mirrors and palleted items are excluded from this deal.

Shipping Fees

We also offer shipping at the following rates:

Standard-Size Parcel

Standard (UK Only) - 2-3 Days - £2.99

Express (UK Only) - 1-2 Days - £4.99

International (EU) - 3-7 Days - £14.99

International (ROW) - 5-10+ Days -£23.99


Large Parcel

Standard (UK Only) - 2-3 Days - £2.99

Express (UK Only) - 1-2 Days - £4.99

International (EU) - 3-7 Days - £14.99

International (ROW) - 5-10+ Days - £69.99

Most UK orders will be sent using Royal Mail, with larger items being sent with DPD.

International orders within the EU will normally be dispatched with Royal Mail, DPD, or UPS.

International orders to the rest of the world will normally be sent with DPD or UPS.

Please note, international delivery charges are very volatile and subject to change. We will do everything in our power to honour the delivery fee, however, in some cases, shipping may increase in price. In this event, you will be given the offer to pay the difference or cancel the order and receive a full refund.

Please note, we may be subject to various rules and restrictions in relation to some international deliveries, and you may be subject to additional taxes and duties over which we have no control. If such cases apply, you are responsible for complying with the laws applicable to the country where you live and will be responsible for any such additional costs or taxes.

Dispatch Times

Orders placed before 15:00 Monday - Friday will be shipped on the same day. 

Orders placed after this time will be shipped on the following business day,

Please note, we are closed at weekends, as well as English Bank Holidays.

Returns Policy

Our refund policy can be found at the following address: https://esupplyline.com/policies/refund-policy.

Further Information

You can contact us for further information on our shipping policies using the following:

Phone: 01953 711 881

Email: sales@esupplyline.com

Live Chat: Available on our website, Monday - Friday, 8:30 - 17:00.

Contact Form: https://esupplyline.com/pages/contact

View full details

Description

Würth Painter's Acrylic Filler is a high-quality acrylic sealant designed for sealing expansion joints and window sealing in interior and exterior applications. The silicone-free, acrylic resin dispersion provides elasticity, UV resistance, and reliable adhesion to common building surfaces. EMICODE EC1plus certification confirms very low emissions and environmental compatibility. The product meets fire safety requirements (Class E in accordance with DIN 4102, Building material class B2) and has been tested to EN 15651 Part 1 standards.

Elastic Movement Accommodation

Expansion joints in buildings experience continuous movement due to thermal cycles, structural settling, and vibration. This acrylic's high elasticity absorbs these movements without cracking, maintaining joint integrity over time. Breaking elongation of 250% ensures the sealant can flex with structural demands.

Paint and Plaster Finishing

The sealant accepts both conventional paints and plaster finishes, allowing seamless decoration matching. However, when joints are fully painted over, the paint coating is less elastic than the sealant beneath and may crack if movement occurs. Partial painting or plaster finish reduces this risk.

Window Sealing Systems

For dual-seal window systems, Painter's Acrylic Filler is used for interior sealing while a dedicated window and façade sealant handles exterior exposure. This staged approach provides optimal protection and allows different material properties optimised for each side of the window assembly.

Application Limitations

This product is not suitable for structural building joints in accordance with DIN 18540 or for bonding and cavity filling. Wide expansion joints should be pre-filled with polyethylene backer rod to ensure proper joint proportions and curing. Standing water should be prevented in joints to avoid erosion.

Environmental Compatibility

The product is EMICODE EC1plus certified, indicating very low emissions and health-compatible composition. The silicone-free formulation prevents corrosion concerns associated with silicone sealants on sensitive metals, though the acrylic base may cause corrosion on steel, copper, and zinc-plated surfaces.

More Information

Application Instructions

  1. Prepare surfaces — Ensure adhesion surfaces are clean, dry, and firm. Remove dust, loose material, and contaminants that would impair bonding.
  2. Apply primer if needed — On absorbent or porous surfaces, apply a primer (such as Silicone primer) to improve adhesion before applying the sealant.
  3. Pre-fill wide joints — For expansion joints wider than standard dimensions, pre-fill with polyethylene backer rod to ensure proper joint proportions and uniform curing.
  4. Load the cartridge — Insert the 310ml cartridge into a standard caulking gun. Cut the nozzle to achieve the desired bead width.
  5. Apply the sealant — Dispense the acrylic filler into the joint in a continuous, smooth bead. Avoid trapping air pockets or creating voids.
  6. Smooth and finish — Tool the joint while wet to achieve a uniform profile and ensure proper contact with substrate surfaces.
  7. Allow skin formation — Allow a minimum skin-formation time of 10 minutes before any finishing or painting.
  8. Paint or plaster — Once fully cured (approximately 1mm per day at 23°C and 50% relative humidity), paint or plaster over the joint as required. Avoid complete paint coverage if future movement is anticipated.
  9. Ensure ventilation — Provide adequate ventilation during the curing phase to allow moisture release.

Safety note: Test compatibility with paints, lacquers, and glazing formulations before full application, as the wide variety of formulas available may interact with the acrylic. Apply only within the processing temperature range of 5°C to 40°C. Curing is significantly delayed in cold, damp weather.

Specifications

Product Type Acrylic painter's filler / expansion joint sealant
Brand Würth
Volume 310 ml cartridge
Chemical Basis Acrylic resin dispersion
Silicone Content Silicone-free
Colour White
Density 1.57 g/cm³
Odour Characteristic (odourless)
Full Curing Speed 1 mm per day
Fully Curing Conditions 23°C and 50% relative humidity
Skin Formation Time Minimum 10 minutes
Breaking Elongation Minimum 250% (for 2mm film)
Continuous Motion Absorption 20.0%
Shore A Hardness 10
Temperature Resistance -20°C to +80°C
Processing Temperature 5°C to 40°C
Paintable Yes
Plaster-compatible Yes
Water-Vapour Diffusion Resistance μ value 24000
UV Resistant Yes
Stability Under Load ≤ 3 mm
Volume Loss ≤ 25%
Tensile Behaviour After Water Immersion ≥ 100% (at 23°C)
Fire Behaviour Class E; Building material class B2 (DIN 4102)
Environmental Certification EMICODE EC1plus (very low emissions)
Durability Passed (EN 15651 Part 1)
Shelf Life 24 months (at 5°C to 25°C)
NOT Suitable For Structural building joints (DIN 18540); bonding; cavity filling; use with pre-compressed sealing tapes

FAQs

Can I paint over this acrylic filler?

Yes; the sealant accepts both paint and plaster finishes. However, when fully painted over, the paint is less elastic than the sealant and may crack if joint movement occurs. Partial painting or plaster finish is preferable if movement is anticipated.

Will this work on all building surfaces?

This filler bonds reliably to standard construction surfaces including plaster, concrete, timber, and plasterboard. A primer improves adhesion on absorbent or porous surfaces. Always test on absorbent or porous surfaces, alkyd resin paints, and powder-coated aluminium before full application.

How long does it take to cure?

Skin forms in approximately 10 minutes at 23°C and 50% relative humidity. Full curing progresses at approximately 1mm per day under the same conditions. Curing is significantly delayed in cold, damp weather.

Can I use this for large expansion joints?

Wide expansion joints should be pre-filled with polyethylene backer rod to ensure proper joint proportions and uniform curing. The product is not suitable for structural building joints in accordance with DIN 18540.