Glass Microballoons

Glass Microballoons


Low-cost, low-density microscopic sodium borosilicate hollow glass spheres can be mixed into epoxy systems and polyester resins to thicken and extend without adding weight. Creates a lightweight, sandable compound ideal for fairing.

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  • Lightweight glass balloons or bubbles that are easy to sand when cured. Perfect for smooth finish work.
  • Provides good impact strength
  • Can be used alone or blended with TotalBoat Silica Thickener (sold separately) to prevent sagging on vertical and overhead surfaces
  • Color: White
  • Size: Available in 1-Quart and 5-Quart sizes
  • Always wear proper safety protection when blending Glass Microballoons and other fillers into mixed resin/hardener, and when sanding
  • Not recommended for gluing

Where to use TotalBoat fillers

Add these Glass Microshperes to epoxy to create a lightweight fairing compound that’s easy to sand or shape. If sagging is a concern, Silica Thickener may be added. TotalBoat fillers can be used with either epoxy or polyester resins to change the resin properties for various uses, such as bulking out the resin or making it easy to sand. Because fillers can affect the pot life of a resin, create a small trial batch first to determine how much working time you’ll have.

Glass Microballoons Milled Glass Fibers Silica Thickener
Fairing ✔ (blended with Glass Microballoons)
Filleting ✔ (blended with Glass Microballoons)
Vertical Surfaces ✔ (in thick enough concentration)
Reducing Shrinkage
Reducing Weight
Surfboard or Sailboard Repair


TotalBoat Glass Microballoons SDS

Frequently Asked Questions

What are Microballoons used with epoxy for?

Microballoons are used to thicken epoxies, and to create a lightweight fairing material that can easily be shaped, sanded, and painted. Epoxy with microballoons added offers a great strength to weight ratio, ideal for shaping, filling cracks, fixing chips and dings, and resurfacing.

What is the advantage of using Microballoons instead of other fillers?

Microballoons make it easier to sand or shape epoxy systems and polyester resins because it thickens and extends without adding weight, and adheres well to styrene, resin, and fiberglass.

Can Microballoons be combined with other fillers?

Yes. Oftentimes, using two fillers is more effective than using a single one because of the synergistic effects that occur when two particle sizes are mixed together. Using multiple fillers makes it smoother and easier to spread.

Are Microballoons lighter or heavier than Cabosil?

Microballoons are lighter than Cabosil, making it easier to sand or shape. Only use Cabosil if looking for a heavier, higher-strength filler.

Can putties made with Microballoons be sanded?

Yes. It makes the compound easier to sand after curing since the resin and thickening agent results in a cured substance which is very hard to sand smooth.

How much of this filler should you add to epoxy?

Because fillers can affect the pot life of a resin, create a small trial batch first to determine how much working time you’ll have. You should aim for a pudding-like consistency. If the mixed resin and filler is runny, add a little more microballoons. If it looks too thick, add a little more resin.

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