Bonded hollow sphere foams for this study were made from point-contact, slurry-bonded monosized spheres, 2.5 mm in diameter. The permeabilities of these foams are compatible with the diffuser base in radiant burners. For this study, the effect of quantity of bonding phase on interstitial porosity, permeability, and uniformity of gas flow through the foams was investigated. The relationship between permeability and porosity was modeled with the Kozeny-Carman equation. Attempts were made to correlate diffuser base permeability to operating characteristics of these burners.