here are the specifics on the spray equipment
The following recommendation is for Graco equipment. Other manufacturers with comparable pumps may also be used.
Liquid Rubber must be thinned with solvent to achieve a sprayable viscosity. See recommendations below.
Equipment capable of spraying Liquid Rubber
Pump Model | Max. Pressure | Fluid Flow | | Hose ID | Max. Hose Length |
Graco GH733 | 3500 psi | 3.0 gpm | | 1/2 inch | 150 feet |
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Graco GH3640 | 36000 psi | 3.8 gpm | | 1/2 inch | 150 feet |
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Roof Rig | | | | | |
Gun | Should be rated for spraying mastics. A 30-40 inch tip extension is recommended |
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Tip Size | .017 to .021 with a 12 inch fan width |
Note: Do not use a “whip” between hose and gun. This reduces flow and pressure which results in poor atomization.
Thinning Liquid Rubber
The “as shipped” viscosity of Liquid Rubber is 34-37,000 cp which is too high for spraying. By adding one gallon of Xylene Solvent to a 5 gallon pail the viscosity drops to 10,000 cp at 75° F. More solvent may have to be added at lower temperatures.
The spray atomization can be improved using a smaller tip size or adding more solvent to reduce viscosity.
Wash solvent from previous pump cleaning can be used for thinning after it is strained to remove dirt.