Compressor-Free Polystyrene injector

Polystyrene Injector for Wall Insulation Without Access.

If you need to insulate your walls but have no access or cannot cut openings to insert polystyrene panels or rock wool, this custom tip allows you to inject polystyrene beads directly into the walls.

This method has the advantage of not requiring a compressor or an injection gun, which can be expensive (around 130€ for the latter in my case).

Designed for use with a vacuum that has a blower function (such as the Karcher WD3), this injector uses the Venturi effect by connecting the vacuum in blow mode and attaching a flexible conduit to suction the polystyrene beads. Insert the tip into a hole matching the outlet size, turn on the vacuum, and adjust the suction conduit to keep it close to the bead surface in the bag.

! WARNING ! Only use fireproof polystyrene beads, as standard polystyrene is highly flammable.

Printing:

• PLA should be strong enough, but PETG was used here.
• For better durability, I recommand at least 3 perimeter walls (I used 4 since the part is handled roughly).
• To improve adhesion, use mouse ears on corners and ends (I used the "Tab+ Antiwarping" plugin in Cura).
• The sloped section can theoretically print without supports, but I preferred using them (especially where the inner conduit reaches 60°).

It worked very well for the first 2000L (2m³) and will be used again for another batch of the same size. Hope you find it useful!"