Silica aerogels are ultralight superinsulators that can increase the efficiency of insulation materials up to three times. In this study, hydrophobic silica aerogels were synthesized using an inexpensive and available water-glass precusor at ambient pressure, without the need for specific equipment using the sol-gel method. Formation of silica aerogels was confirmed using FT-IR, SEM, TEM, BET and BJH methods. Thermal stability and hydrophilicity of silica aerogels were investigated by TGA and by contact angle measurement, respectively. Then, composites including an equal amount of anti-corrosion of alkyd resin-zinc Chromate containing weight percentages 0, 1, 5, 10, 20, 30, 40 and 50 were prepared from silica aerogels. The thermal conductivity of the composites was measured in liquid state. The results indicated a significant decrease in the thermal conductivity by increasing the weight percentage of silica aerogel. The composite adherence was then evaluated. Composites with the highest amount of aerogel with proper adherence according to the standard set by the National Gas Company of Isfahan province, along with paint thinner for dilution and colorless cobalt drier, were coated on aluminum plates of thickness of 1.2 mm and the thermal conductivity of the film was measured in dry state. The results of this study showed that the composite containing 30% by weight of silica aerogel and B 5 adherence had the least thermal conductivity and it can be used as a thermal insulation of various equipment in the gas industries.