A characteristic of the 3M™ Ultrapro™ MSP Sprayable Seam Sealer and the Sprayable Seam

Sealer Applicator Gun (PN 08400) is that some sealant continues to flow out of the nozzle after

the trigger is released. In order to control this flow of sealant, a purging method to remove the

excess sealant in the nozzle was developed. The correct purging method is as follows:

Change the plunger pressure (blue valve) to 0 and set the air atomization pressure (red valve)

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at 4 or lower.

Squeeze the trigger on the applicator gun to 1/3 of the full trigger stroke. Do this twice in

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rapid succession. This will clear nearly all of the sealant from the outer gun nozzle.

Caution: Make sure the plunger pressure (blue valve) is at 0 and do not set the air atomization

valve (red valve) any higher than 4 during this procedure. Failure to do so will create

backpressure in the gun and cause the sealant to reverse discharge into the length of the gun

barrel. This will cause the gun to fail and void any manufacturer warranty.

Pressure Valve Settings

Technicians will need to adjust pressure settings and vary nozzle tip distances from the surface

in order to achieve the desired appearance of a bead, sprayed seam or coating. The airline

pressure to the Sprayable Seam Sealer Applicator Gun should be controlled with a pressure

regulator between 50-95 psi. Do not exceed 95 psi.

When the applicator gun pressures and the distance from the surface are adjusted appropriately,

no overspray is observed. If overspray is experienced, check the air pressure to the gun. The

following gun pressure valve settings are listed as general guidelines for producing the desired

patterns:

• Beads:

Turn the red valve to 0 and adjust the blue valve to:

Narrow Bead –

3 to 4

Wide Bead –

5 to 6

Heavy Bead –

7 to 8

• Sprayed Seam:

Adjust the blue valve to

5

Adjust the red valve to

2.5 – 3

* Spray at a distance of 1-2” from the surface to minimize overspray.

• Coating:

Adjust the blue valve to

5

Adjust the red valve to

2.5-3.5

* Spray at a distance of 10-12” from the surface to minimize overspray.

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