Best Void Filling Foams

1. Fiberglass Supply Depot 6 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boats, Dock Flotation, Carving, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)

Fiberglass Supply Depot’s 6 Lb. Density Expanding Pour Foam is a 2-part polyurethane foam perfect for boats, docks, and insulation. It’s easy to mix and pour, making it great for DIY projects.

This 1-gallon kit includes equal parts A and B, creating 1.5 cubic feet of foam. It’s ideal for soundproofing, filling voids, and adding buoyancy.

The foam cures fully without melting under resins like polyester or epoxy. It’s also temperature-sensitive, working best at 75° to 80° F for optimal expansion.

2. TotalBoat 2lb Density Expanding Closed Cell Polyurethane Boat Foam – 2 Gal

TotalBoat 2lb Density Expanding Foam is a lightweight, two-part polyurethane foam perfect for marine use. It’s ideal for adding buoyancy, insulation, and soundproofing.

This foam is easy to use with a 1:1 mix ratio. It expands quickly and hardens in about 5 minutes at 70-80°F. Use it to fill gaps or voids under boat decks.

The 94% closed-cell structure resists water, gas, oil, and solvents. Once cured, it can be coated, cut, or carved to fit your needs. Available in 2 quart and 2 gallon kits for different projects.

3. Expanding Foam Packaging Expanding Packing Foam for PC, Fragile & Irregular Valuables Items, Electronics, Ceramics, 22″x27″ Expandable Packing Foam for Shipping & Moving #80 (4 PACK)

Protect fragile items with ease using expanding foam packaging. It’s perfect for shipping and moving delicate goods. The foam fits any shape, keeping items safe.

This foam fills gaps quickly and prevents shifting. It’s lightweight and easy to store, saving space in your warehouse.

Pack of 4 bags, each 22″x27″, works well for 12″x18″x12″ boxes. Just squeeze, mix, and place for instant protection. Simple and effective for all your packing needs.

4. Bubblefast! Brand 7 cu ft (45 gallons) Pink Anti Static Packing Peanuts Popcorn (Two 3.5 cu ft Bags)

Bubblefast! Packing Peanuts are lightweight and anti-static, perfect for cushioning and protecting items during shipping or moving. They come in two 3.5 cu ft bags, totaling 7 cu ft (about 45 gallons), making them easy to use and store.

These pink peanuts are 100% recyclable, interlock for resilient cushioning, and work great for bean bags or planter pots. Simple, effective, and versatile!

5. QUTOOL White Shredded Memory Foam Filling, 0.44 lb for Pillows and Crafts

QUTOOL White Shredded Memory Foam is perfect for filling pillows, bean bags, and crafts. It’s made from premium memory foam, cut into cubes for comfort and breathability. Use it to refresh old cushions or create new, comfy pet beds.

This long-lasting foam keeps its shape, so it never goes flat. Just open the vacuum-packed bag, let it expand, and enjoy soft, supportive filling for years.

6. Spray Foam (Grabs in 60 Seconds) Polyurethane Foam Adhesive

Spray Foam grabs in 60 seconds, making it perfect for quick jobs. It’s ideal for vertical use and time-sensitive repairs. No more waiting—just fast, reliable results.

The foam expands cleanly and neatly, reducing mess. It’s great for window frames, door frames, and insulation boards. Creates a secure bond every time.

This all-weather foam works indoors and outdoors. It fills gaps and cracks with high strength. One can covers up to 147 feet for multiple projects.

7. UOFFICE Anti Static Packing Peanuts 3.5 cu. ft

UOFFICE Anti Static Packing Peanuts are perfect for protecting your items. They come in a 3.5 cubic feet bag.

These pink Styrofoam peanuts are S-shaped and fill about 26 gallons. They are great for loose void fill in your boxes. Use them to keep your shipments safe.

The anti-static feature stops dust from sticking. They create a strong cushion for your items. Your valuable shipments will stay protected.

8. Fiberglass Supply Depot 2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)

Fiberglass Supply Depot’s 2 Lb Density Expanding Pour Foam is a 2-part polyurethane foam perfect for boats, docks, and insulation. Just mix equal parts of Part A and Part B to create a lightweight, closed-cell foam. It’s great for soundproofing, filling voids, and adding buoyancy.

This foam is easy to use and expands quickly. It’s ideal for nonstructural applications like filling spaces under decks or inside cavities. Once cured, it can be laminated with polyester, epoxy, or vinyl ester resins without melting.

For best results, work in temperatures between 75° to 80° F. Measure accurately and mix thoroughly. The foam expands fully in about 5 minutes, giving you a reliable, durable solution.

9. FGCI Expanding Foam 2 Gallon Kit, 8 Lb Density 2-Part Marine Foam

FGCI Expanding Foam is a 2-part polyurethane foam that expands quickly when mixed. It fills voids, hulls, and cavities with a rigid, closed-cell structure. This 8 lb density foam offers strength and flotation, perfect for marine and structural use.

The 2-gallon kit includes pre-measured parts A and B, ensuring accurate mixing. Made in the USA by Fiberglass Coatings, it’s backed by 60+ years of expertise.

10. Fiberglass Supply Depot 2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)

Fiberglass Supply Depot’s 2 Lb Density Expanding Pour Foam is a 2-part polyurethane foam perfect for boats, docks, soundproofing, and insulation. Just mix equal parts of Part A and Part B, pour it in place, and watch it expand to fill spaces or add buoyancy.

This foam is lightweight, easy to use, and works best at 75° to 80° F. It cures fully in about 5 minutes and can be laminated with polyester, epoxy, or vinyl ester resins.