AC 38


Virtually odourless and easy to finish.

Can be covered after 1 hour with all paints and varnishes.

Moisture and condensation resistant.

Safe on all building materials.



  • 529100000 - AC 38 white - cartridge 310ml


The professional acrylic mastic used to seal and fill all construction materials. The formulation ensures a perfect finish with all types of paint, stains and varnishes, with little or no risk of reactions such as blistering or discolouration. AC38 sets to a plastic consistency which is perfect to take up expansion and movement in the substrate without loosening or cracking.


Sealing and finishing of joints, gaps and cracks before overcoating.

Sealing of joints between frames, walls, window sills, skirtings, etc.

Repairs and sealing of cracks and joints in aerated concrete, stone, plasterwork and woodwork.

Sealing of angle and panel joints in interior construction.

Filling drill and screw holes in walls and ceilings.

Strenghtening weak substrates. 

Technical information


AC 38


  • Base: acrylate.
  • Odour: low.
  • Colour: white.
  • Relative density (DIN 53479): 1.56 g/ml.
  • Skinning time (at 23°C and 50% relative humidity): 10 minutes.
  • Volume change (ISO 10563): ≤ 24%.
  • Ambient application temperature: from +5°C to +40°C.
  • Temperature resistance after setting: from +20°C to +70°C.
  • Tensile strength (DIN 53504 S2): 0.68 N/mm².
  • Elongation at break (DIN 53505): 200%.
  • Movement capacity: 7.5%.
  • Shore A hardness: 38.
  • Modulus at 100% strain (DIN 53504 S2): circa 0.65 N/mm2.
  • Storage life: 18 months in a dry place. The product may freeze down to -15°C during transport without loss of quality).
  • Safety measures: please consult the safety datasheet.


  • Apply to clean and dry or slightly damp substrates.
  • Strike off dry or wet with a spatula.

Paintable after 1 hour, depending on temperature and air humidity. Remove any masking tape before the skin forms to prevent damage.

Improve adhesion and reinforce weak substrates such as aerated concrete or plaster by coating with diluted AC38 (2 parts water to 1 part AC38).

Test the adhesion to plastics, powder coatings, exotic timbers, Belgian bluestone and bituminous materials.

A perfect joint will be as deep as it is wide (from maximum 5 to 10 mm).


The drying time depends on:

the temperature of the product

the ambient temperature

the temperature of the substrate

the coat thickness

the air humidity

the humidity of the substrate.

Not to be used as glazing putty or as an adhesive sealant. Not suitable for submerged joints or in locations with standing water.

Technical documents

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