Spray Techniques

Spray Techniques

Recommended Nozzle Selection Chart

Application

Nozzle Size2

Air Volume1

Simulated

6 mm, white

medium to

Acoustic

(fine to medium)

high

 

8 mm, gray

 

 

(coarse)

 

Orange peel

4 mm, beige,

medium to

 

6 mm, white

high

Splatter

6 mm, white

low to

coat

8 mm, gray

medium

Knockdown

8 mm, gray

low

 

12 mm, black

 

1Control air volume with gun air valve.

2For more material volume try a larger nozzle.

Adjusting the System

Sufficient fluid output (volume and pressure) and good atomization is a balance of atomozing air, material thickness/material flow and nozzle selection. Achieving the correct balance for your application requires experimentation to achieve desired results. Keep in mind these important points when adjusting gun:

Select proper nozzle for your application. See Nozzle Selection Chart. Remember, the larger the nozzle, the heavier the pattern.

Start sprayer with gun air flow valve completely open. If needed, slowly close gun air flow until you get a good spray pattern. Use minimum amount of air at spray gun to achieve proper spray pattern and to minimize bounce back.

To Get Less Material

Try one or a combination of these methods:

Open air valve.

Turn gun flow adjustment nut to decrease flow, counter-clockwise.

Use smaller nozzle.

To Get More Material

Try any one or a combination of these methods:

Close air valve.

Turn gun flow adjustment nut to increase flow, clockwise.

Use thinner material mixture.

Use a larger nozzle.

Preventing Material Surge at Gun Trigger

Pressure will build up in the system when you stop triggering the gun. To prevent material surge at initial gun triggering:

Point gun away from surface you are spraying when you first pull trigger.

When you first start to spray, hold the gun away from the surface and gradually work your way closer to it.

Keep gun moving.

After you begin spraying, trigger the gun as little as possible.

+Test spray pattern on cardboard. Hold gun 18 to 24 in. (45.7 to 60.9 cm) from surface. Use this spraying distance for most applications.

Air and material flow adjustments are made at the gun on all units. RTX 1250 units have a material flow control selector knob (L).

+Opening air valve increases air flow through gun, which decreases texture material flow through pump.

+Closing air valve decreases air flow through gun, which increases texture material flow through pump.

For Continuous Spraying

Use trigger lock to hold trigger open and reduce fatigue.

Check Material Consistency Periodically

Check and thin material as needed to maintain proper consistency. The material may thicken as it sits and slow down production. Agitate periodically.

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Graco 1250, 900 important safety instructions Spray Techniques