Q-Cells are microscopic, hollow glass microspheres used as a lightweight filler in marine and composite applications. They are added to resin systems—typically epoxy, polyester, or vinyl ester—to create fairing compounds and low-density putties that are easy to sand and shape.

Both are lightweight fillers for fairing, but Q-Cells are made from hollow glass, which makes them slightly harder and more moisture-resistant than phenolic microballoons. Q-Cells may be slightly more difficult to sand but offer better compressive strength.

To achieve a peanut butter-like consistency for troweling or fairing, mix approximately 2 parts Q-Cells to 1 part resin by volume. Adjust as needed depending on the desired thickness and application.

No. Q-Cells are intended for fairing and cosmetic work, not for structural bonding. If strength is required, consider blending Q-Cells with a high-strength filler like colloidal silica or chopped fiberglass for reinforcement.

Yes, Q-Cells create a fairing mix that is lightweight and easy to sand—one of their main advantages. This makes them a favorite among boatbuilders for final surface prep before painting.

Yes, Q-Cells are compatible with epoxy, polyester, and vinyl ester resins. They are extremely versatile for a wide range of applications in fiberglass and composite work.

Match the filler to the job, and keep strength fillers below the surface with fairing fillers on top:

• Bonding and structural fillets: use a high-density or fiber filler like colloidal silica (Cabosil), milled fiber, or microfibers, which cure hard and strong.
• Fairing and shaping: use a low-density filler like phenolic microballoons, glass bubbles, or a fairing compound, which sand and feather easily.

Adhesive, high-density fillers like colloidal silica and microfibers make a hard, strong mix for bonding and structural filleting, but they are tough to sand. Fairing, low-density fillers like microballoons and glass bubbles make a light, soft mix that sands and feathers easily for a smooth surface, but they are not structural. Use adhesive fillers for strength and fairing fillers for finish.

There is no fixed ratio. Mix the resin and hardener fully first, then stir in filler a little at a time until you reach the consistency the job needs:

• Ketchup consistency: for a coating or pre-coat that still flows.
• Mayonnaise consistency: for bonding parts together.
• Peanut-butter consistency that holds a peak: for filleting and gap-filling.

Low-density microsphere fillers sand the easiest. Phenolic microballoons, 3M glass bubbles, and lightweight blends like our fairing compound or West System 410 Microlight feather to a fine edge and carve with little effort once cured. They trade strength for sandability, so use them above the structural layer for shaping and smoothing, not for bonding or load-bearing fillets.

Some are. High-density and fiber fillers like colloidal silica, milled glass fiber, and microfibers add real strength and are made for bonding and load-bearing fillets. Low-density fairing fillers like microballoons and glass bubbles are not structural; they are for shaping and fairing only. Build strength with a high-density filler first, then fair over it with a low-density filler.