A foil balloon (or Mylar balloon) is an inflatable manufactured from thin metallized polymer films—typically high-barrier Nylon (PA) laminated with LLDPE Polyethylene and vacuum-coated with pure aluminum. Unlike porous latex, its airtight hermetic barrier retains helium for days and supports high-definition rotogravure printing.

Helium Gas is required for free floating (standard 18" rounds, jumbo 34" numbers, and 3D spheres). Regular Air is used for stationary decor (arches, backdrops, stick mounts), remaining taut and rigid for months as oxygen/nitrogen diffuse extremely slowly.

Insert a smooth pump nozzle 2-3 inches into the tail inflation channel marked by the slip sheet. Inflate steadily to 90%-95% full to allow thermal expansion margin, then pull the nozzle out and pinch the tail flat. The internal LLDPE flap automatically seals shut.

Helium-filled 18" foil balloons float for 5 to 7 days indoors; jumbo 34"/40" sizes remain buoyant for 2 to 4+ weeks. Air-filled balloons stay rigid for several months due to low gas permeability across high-barrier Nylon film.

Non-floating occurs when upward helium lift is smaller than film deadweight. Common causes: (1) Balloons under 18" holding insufficient gas volume; (2) Complex narrow shapes adding excess seam weight; (3) Diluted low-purity helium (<99.9%).

Thermal Shrinkage: Cold air contracts helium (Charles's Law), causing temporary wrinkling that reverses upon entering room temp. Physical Leakage: Caused by torn valves or over-inflation seam ruptures. FAIR performs 48h pressure tests on 100% of batches.