VFI®-5155 5 PCF Slow Rigid Polyurethane Foam

VFI®-5155 5 PCF Slow Rigid Polyurethane Foam

VFI-5155 5 PCF Slow Rigid Polyurethane Foam is a two-component, water-blown, expanding foam with good compression strength and structural integrity. With a slow initial rise, the foam has a generous work time, allowing parts to be hand poured or used in a machine injection system. Rigid foam is a great alternative to producing costly plastic parts and is highly machinable. Cast parts can be demolded within the same day for a quick return to service. VFI-5155 has been used to make lightweight parts and shapes for manufactured stone, precast, prototyping, and other industrial applications. Depending on application needs, VFI also offers a faster 5-pound foam variation (VFI-5105) for quicker demolding.

VFI-5155 5 PCF Slow Rigid Polyurethane Foam from VFI is a water-blown, expanding foam with a generous work time for making lightweight parts and shapes.

Features & Benefits

  • Works as a lightweight casting, void filling, or backfilling material
  • Provides a uniform surface that can be sanded, painted, or top coated
  • Convenient 1:1 mix ratio by volume for quick and easy application
  • Slower rise time allows for easy pouring of larger castings or parts

Instructions for Use:

Mold Preparation

Molds must be clean, dry, and free of contaminants such as dirt, debris, oils, or other residues. Porous molding surfaces such as wood, natural stone, and concrete must be sealed and released to prevent unwanted adhesion. Spray a uniform layer of release across the entire surface and wait for it to dry before adding more. Using a release agent will help extend the life of the mold.

The mold must be strong enough to hold shape if subject to packing pressure. Some rubber molds may require a stiffer outer mold, as the expanding foam may push and deform the mold if it is not rigid enough. A cold mold will provide less expansion and a less uniform skin on the foam, so the mold should be heated to at least room temperature. Heated molds up to 120°F are acceptable, but heating the mold past 72°F will decrease the pot life. Compatible molds for casting include metal, urethane, epoxy, and platinum silicone.

Mixing, Pouring, & Curing

The foam is sensitive to cold temperatures, so the material, mold, and work area should be at least at room temperature for the best results. The B side material (Poly) must be premixed until uniform. Mix the foam with a drill or power mixer. Pour the measured B side into the measured A side (Iso). Mix rapidly, moving the mixer through the center until uniform. Transfer the mixture to a new container and mix again before use. The material must be completely mixed before the initial rise.

After mixing, the material should be immediately poured into a mold or form. Pour in one spot at the lowest point of the mold and allow space for the foam to expand. Do not overload foam into closed molds to prevent distortion. Avoid scraping material from the container, as the material may not be completely mixed, and the foam may begin to expand before you are finished pouring.

Avoid moving the foam as it rises since movement could cause the cells to collapse before it fully cures. Allow the casting to remain in the mold or form for at least 1 hour at room temperature to prevent deformation. Demold time will vary based on material volume, temperature, mold type, etc. Thinner pours may require a longer cure time.


Clean equipment with xylene or MEK before the foam cures. If the foam has cured, you can break it off the surface and wipe the rest off with xylene.


*Always read the safety data sheet before working

Use chemicals only as directed and for their intended purpose. Do not dispose of chemicals down the drain. Most chemicals must be disposed of as hazardous waste.

PPE to avoid all unnecessary exposure:

  • Eye protection – wear properly fitted, chemically resistant safety glasses or goggles. Use a face shield if a splashing hazard is present
  • Hand protection – wear chemically resistant protective gloves to avoid skin contact. Suitable materials include chloroprene rubber (Neoprene), nitrile rubber (Buna-N), chlorinated polyethylene, polyvinyl chloride (Pylox), and butyl rubber
  • Body protection – wear suitable protective clothing and cover as much exposed skin as possible to prevent all skin contact. Suitable materials may include saran-coated material
  • Respiratory protection – in case of insufficient ventilation, wear suitable respiratory equipment. Respirator selection must be based on known or anticipated exposure levels, the hazards of the product, and the safe working limits of the selected respirator

Product Limitations

VFI-5155 contains isocyanate that may be irritating to the skin and is toxic if inhaled as particulate matter. Avoid prolonged breathing of vapors and repeated skin contact. It is not UV color stable and has no long-term UV testing.

  • Incompatible materials – A side: acids, amines, alcohols, water, alkalines, strong bases, and substances or products that react with isocyanates. B side: oxidizers
  • Conditions to avoid – A side: avoid moisture and freezing. B side: heat and incompatible materials
  • Chemical stability – the product is stable if stored and handled as prescribed/indicated
  • Reactivity – A side: no corrosive effect on metal. Based on its structural properties, the product is not classified as oxidizing. B side: no dangerous reaction known under conditions of normal use
  • Possibility of hazardous reactions – A side: reacts with alcohols, acids, alkalines, amines, and water with the formation of carbon dioxide. Risk of bursting, exothermic reaction, and polymerization. Contact with certain rubbers and plastics can cause brittleness of the substance or product with subsequent loss in strength. B side: no dangerous reaction known under conditions of normal use
  • Hazardous decomposition products – A side: carbon monoxide, carbon dioxide, nitrogen oxides, hydrogen cyanide, aromatic isocyanates, and gases/vapors. B side: may include, and are not limited to, oxides of carbon

Potential Health Hazards

  • May cause respiratory tract irritation. A side material may also cause allergy and asthma symptoms or breathing difficulties if inhaled.
  • Causes skin irritation or sensitization: redness, edema, drying, defatting, and cracking of the skin.
  • Causes serious eye irritation: discomfort, pain, excess blinking and tear production, marked redness, and swelling of the conjunctiva.
  • May cause stomach distress, nausea, or vomiting if swallowed.

*If you are experiencing any of these symptoms, seek medical advice or attention. Call a poison control center or doctor if swallowed.

Application Methods:

  • Inject Inject
  • Pour Pour

Available Packaging:

  • Tote
  • Drum
  • 5 Gallon
  • 1 Gallon