Handheld gas spray systems for mixing and dispensing multi- component compositions. The system comprises a fluid conveyance subassembly in fluid communication with a syringe, wherein the syringe houses at least two different sealant components. The system comprises further a housing, a gas cartridge disposed inside the housing and a gas valve assembly disposed inside the housing, wherein the gas valve assembly is configured to control flow of gas from the gas cartridge to the fluid conveyance subassembly. A trigger is configured to actuate the gas valve assembly and a detachable spray tip is configured to dispense the multi-component fluid out of the applicator.