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3M™ Glass Bubbles K25, Large Box (410 lb, 186 kg)

3M ID 98021233162
  • Lower viscosity, improved flow
  • Increased filler loading, reduced cost
  • VOC reduction
  • Chemical stability and inertness
  • Lower viscosity, improved flow
  • Increased filler loading, reduced cost
  • VOC reduction
  • Chemical stability and inertness
  • Reduced dielectric constant
  • Thermal conductivity reduction
  • Temperature resistance

3M™ Glass Bubbles K25 have a density of 0.25 g/cc and an isostatic crush strength of 750 psi.

What are 3M™ Glass Bubbles?The general purpose K Series glass bubbles are the most versatile and economical 3M™ Glass Bubbles. Our 3M™ Glass Bubbles K25 are engineered hollow glass spheres made from water-resistant and chemically-stable soda-lime borosilicate glass. Like all 3M glass bubbles, our K25 glass bubbles are water and oil resistant, providing better utility in underwater applications and creating more stable emulsion explosives. Additionally, they are non-combustible and non-porous, so they do not absorb resin; and their low alkalinity makes this product compatible with most resins while providing a stable viscosity and a long shelf life. 3M glass bubbles are a superior alternative to many conventional fillers and additives such as silicas, calcium carbonate, talc, clay and other materials used in demanding applications. Our low-density spheres are used in a wide range of industries to reduce part weight, may lower costs and enhance product properties – making them more reliable and affordable than many alternatives such as cenospheres and perlite. Strength-to-Weight RatioThe benefits don’t end there; although these hollow spheres have thin walls, they have an isostatic crush strength of 750 psi, making them suitable for a number of buoyancy applications, including additives in buoys and shallow water buoyancy applications (e.g. up to 5,000 feet of sea water). K25 bubbles have a fractional survival rate of 80% or more, at 750 psi for consistent performance in highly filled resin systems. The unique spherical shape of these bubbles offers a number of additional benefits, including: higher filler loading, lower viscosity/improved flow and reduced shrinkage and warpage. Higher filler loading offers the potential for lower costs. Adding to this product’s versatility is its ability to be easily blended into compounds – making it adaptable to a variety of production processes including spraying, casting and molding. Buoyancy Benefits and ApplicationsThe ideal combination of high strength and low density has made 3M glass bubbles an industry-standard additive for syntactic foams used in buoyancy modules, buoys or buoyancy blocks for undersea vehicles. When 3M glass bubbles are formulated with resin, the resulting syntactic foam has a high strength-to-density ratio to provide maximum net buoyancy for a given depth rating. The bubbles also produce stable voids, which results in low thermal conductivity and low dielectric constant. Drill Riser Buoyancy Modules3M glass bubbles K25 can be used in a variety of applications. One common application is in drill riser buoyancy modules. Drill riser buoyancy modules are large clamp-on structures that are used on steel risers for all offshore oil and gas drilling. The drill riser is used to offset the weight in water of the riser and all of its associated components. The deep riser buoyancy modules remain stable in high pressure deep water. 3M glass bubbles K25 help to decrease weight of the whole composite structure, allowing it to remain strong, buoyant and lightweight. Typical Applications Paints and coatings Cast polyester Caulk Explosives Polyester putty Polyester putty Sealants Adhesives Adhesives Potting compounds Tooling boards Spackling compound

Chemical Resistance, Lightweighting, Temperature Resistance
Color (unaided eye)
White, powdery
Soda-lime-borosilicate glass
Density (g/cc)
Paints and Coatings, Rubber and Plastic, Transportation
Net Weight (Imperial)
410 lb.
Particle Size (D50 Micron)
Particle Size Range (D50 Micron)
50 - 59, 50 - 59
Hollow spheres with thin walls
Strength (MPa)
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