3M™ Glass Bubbles for Lightweight Sheet Molded Composites

  • Low-density sheet molded composites (SMCs) are a practical and cost-effective alternative to aluminum, magnesium and other metals in many applications – especially in structural and Class A automotive components. For many years, 3M™ Glass Bubbles have helped reduce weight by up to 30% compared to SMCs formulated with conventional fillers such as calcium carbonate, silica or clay. Now 3M glass bubbles can help achieve up to a 40% weight reduction and enable a density under 1.0g/cc!

    Now, there’s a 3M glass bubble solution for all your SMC lightweighting applications, from standard to ultra-light — so you can tailor the optimal balance of performance and cost for your application. Interested in learning more? Contact us to find out how we can partner to meet your lightweighting automotive goals.

Benefits of 3M Glass Bubbles in Automotive Sheet Molded Composites (SMC)

    • Lightweight Plastisol for Seam Seals and Coatings
      • Resin reduction
      • Improved throughput via faster cooling
      • Density reduction
      • Improved dimensional stability
      • Thermal and acoustic insulation
      • Reduced dielectric constant
      • Increased stiffness

    • Scale showing parts with and without glass bubbles

      3M offers compounders and their customers a new generation of glass bubble lightweighting options, from standard to ultra-light, allowing you to tailor the optimal balance of performance and cost for your application. This includes our new 3M™ Glass Bubbles S32HS, making it possible to produce SMCs with densities < 1.0 g/cc. These advanced low-density additives feature a crush strength of 6,000 psi, affording them greater survivability under demanding processing conditions. And because of their small particle size (average diameter: 25 microns) they can be used to create ultra-lightweight parts with Class A paintable finishes.

    • Automotive production line

      Today’s composites are strong enough to replace metal in many applications – at lighter weight and with lower tooling costs. Composites also enable the use of fewer components and more variable geometries.

      With the uncertainty surrounding global metal supply, SMCs are uniquely positioned to provide a cost-effective alternative to steel, aluminum and magnesium. By incorporating 3M glass bubbles, molders and OEMs can reduce overall vehicle weight, improve fuel economy – and gain a competitive edge.

    • Sports car with Class A finish body panels

      Visible parts – especially vehicle exteriors – are held to a higher aesthetic standard than structural components. Metal has traditionally held the edge in flat, smooth surfaces and even light reflection, but SMCs are evolving. Sheet molding manufacturers have achieved Class A surface finishes using 3M glass bubbles with smaller particle sizes – all at a significant weight reduction compared to conventional SMCs.

    • Larger volume of glass bubbles weighs the same as smaller volume of talc

      Don’t be misled by a low cost-per-pound. With 3M glass microspheres, you can reduce a part’s weight, without increasing its cost of production.

      Filler volume vs. weight

      Glass bubble volume is considerably different when compared to an equal weight of higher density mineral fillers. Lightweight glass bubbles can occupy up to 20x more space than an equal weight of mineral filler.

  • Glass Bubbles

    Recommended Products

    • 3M™ Glass Bubbles S32HS For ultra lightweight Class A and structural SMCs with part densities <1.0 g/cc and 40% average weight reduction.
    • 3M™ Glass Bubbles iM16K For lightweight Class A and structural SMCs with part densities of 1.2–1.3 g/cc and 30% average weight reduction.
    • 3M™ Glass Bubbles S28HS For ultra lightweight structural SMCs with part densities <1.0 g/cc and 40% average weight reduction.
    • 3M™ Glass Bubbles S38HS For lightweight structural SMCs with part densities of 1.3 g/cc and 30% average weight reduction.

A Closer Look at SMCs

SMC manufacturers are increasingly replacing heavy fillers with low-density alternatives. 3M glass bubbles can achieve significant weight reductions while maintaining mechanical performance and Class A surface finish.


Made with NEW 3M™ Glass Bubbles S32HS

NEW from 3M: Latest material innovation enables lighter weight, lower density SMC

  • Now, it’s possible to produce SMCs with densities below 1.0 g/cc! 3M glass bubbles S32HS feature a crush strength of 6,000 psi for greater survivability under processing conditions. And because of their small particle size (average diameter: 25 microns) they can be used to create ultra-lightweight SMC parts with Class A paintable surface finishes.

    Learn more about 3M™ Glass Bubbles S32HS

    Contact Us

Connect with us

3M glass bubbles are supported by our global sales, technical and customer service resources. Contact us for more information, including formulation assistance or questions about a specific application.

Call 1800-425-3030 (Mon-Fri, 8:00 AM – 5:00 PM Central Time )


Case Studies

Read about real-world customer applications for lightweight SMCs with 3M glass bubbles.

  • Supplier reduces weight of sheet-molded composite plastic parts by more than 25%.

    Continental Structural Plastics (CSP) reports significant new advances in weight reduction of SMC thermoset parts used in automotive panels, including exterior applications with Class A surface appearance requirements.

  • Plastics News: Glass microspheres lighten up the 2016 Corvette

    Lightweight SMC body panels in the 2016 Chevrolet Corvette shave 20 pounds off the sport’s cars model weight. Developed by Continental Structural Plastics, the sheet molding compound incorporates 3M glass bubbles, passes OEM paint tests and offers low tooling costs compared to steel or aluminum.

  • Plastics News: Glass bubbles lift Corvette body panels to top SPE award

    The top prize in the Society of Plastics Engineers’ 2015 Automotive Innovation Awards went to General Motors Co. for class A body panels made using a lightweight SMC from Continental Structural Plastics. Using 3M glass bubbles, CSP reduced mass by 43% over conventional SMCs and 28% compared to mid-density grades.


ORLANDO – May 7-11, 2018 – National Plastics Expo, Booth #S27153 – As automotive manufacturers look to improve fuel economy and battery range for electrification, material lightweighting without compromising mechanical integrity is vital. Metals, although lightweight, can come with indirect processing and manufacturing costs and may become even more expensive with the uncertainty surrounding global metal supply. Sheet molded composites (SMCs) are a viable alternative to metals in certain applications, while still achieving the desired physical properties. 3M today introduces Glass Bubbles S32HS to help OEMs achieve up to a 40 percent weight reduction of composite parts, at a density below 1.0 g/cc, while still enabling a class A paintable finish. This innovation makes SMCs an attractive option in automotive design for OEMs.

“With the trend toward electric and high efficiency cars, reducing overall vehicle weight is key to staying competitive,” said Ray Eby, vice president of 3M Automotive Electrification. “A typical automobile has about 660 lbs. of composite parts. With ultra lightweight SMCs enabled by our glass bubbles, OEMs can significantly improve a vehicle’s energy usage, while saving money– one less bump in the road in the race to automotive electrification.”

For many years, 3M has partnered with the automotive industry to enable weight reductions for major automotive manufacturers. By replacing conventional fillers, these hollow glass microspheres can reduce the weight of molded parts without sacrificing strength or aesthetics. For the first time, 3M has been able to break the density barrier, making ultra lightweight SMCs more competitive to steel and aluminum, opening up new possibilities for the material mix in automotive applications.

“Our customers continue to challenge us to lower the density and weight of fiberglass reinforced material systems to support their automotive lightweighting efforts,” said Terrence O’Donovan, vice president, marketing and sales for Core Molding Technologies. “A density of 1.0g/cc or below has long been a goal, while still enabling a Class A finish. Using 3M Glass Bubbles helps enable us to meet our customers’ expectations.”

3M glass bubbles are an established lightweighting technology used in enabling lightweight sealants, injection molded parts and SMCs. 3M continues to be at the forefront of automotive lightweight material innovation with the launch of Glass Bubbles S32HS.