What Is a 1.7 Spray Tip Used For and When to Choose It

What specific types of coatings are compatible with a 1.7 mm nozzle size?

A 1.7 mm nozzle is engineered to handle coatings with significant solid content that would otherwise bridge or clog smaller orifices.

• High-build primers utilize this size to level out sanding scratches and surface imperfections quickly.
• Polyester fillers require the wider bore to prevent the heavy, resin-based particles from stalling in the fluid passage.
• Industrial enamels often necessitate this diameter to achieve a wet, glossy finish without requiring excessive thinning that could compromise durability.
• Waterborne primers benefit from the 1.7 mm opening because these materials often have a higher density than traditional solvent-based counterparts.

How does the orifice diameter affect the atomization quality of high-viscosity materials?

Larger orifices decrease atomization quality because they require higher air volumes to break up thick fluids into fine droplets. While a 1.3 mm tip creates a mist-like spray, a 1.7 mm tip produces larger, heavier droplets that demand more precise air pressure settings to avoid a coarse, orange-peel texture.

In what industrial applications is this nozzle size considered the standard?

This nozzle size serves as the baseline for applications requiring thick, protective layers rather than thin, decorative coats.

• Structural steel coating often relies on this tip to apply heavy anti-corrosive primers that must withstand harsh environmental exposure.
• Marine coatings frequently use a 1.7 mm tip to spray thick epoxy barriers that protect hulls from osmotic blistering.
• Wood finishing shops employ this size for applying high-solid base coats or heavy-duty lacquers to raw furniture pieces.
• Automotive restoration work utilizes this tip for high-build primer surfacers that fill deep bodywork pits before final sanding.

What are the primary differences between using a 1.7 mm tip versus a 1.3 mm or 1.4 mm tip?

The primary difference lies in the fluid volume output, where a 1.7 mm tip moves significantly more material per second than a 1.3 mm or 1.4 mm tip.

Use these values to select the smallest orifice that successfully atomizes your specific paint viscosity to minimize material waste.

How does air pressure adjustment influence the spray pattern when using a 1.7 mm nozzle?

Increasing air pressure with a 1.7 mm nozzle forces the heavier material to break apart into smaller particles, which smooths out the finish. If the pressure is too low, the fluid will emerge in large, uneven globs, leading to a textured surface. You must find the balance where the air stream is strong enough to shear the thick liquid without causing excessive overspray.

For example, when spraying a high-build polyester primer, you might need to bump your inlet pressure to 30 psi to make sure a flat, even coat. A nuance exists with high-viscosity coatings, however; if you increase the pressure too much, you may cause the solvent to flash off too quickly, resulting in dry spray or poor adhesion to the substrate.

What is the relationship between nozzle size and fluid delivery rate in HVLP spray guns?

Fluid delivery rate increases proportionally with the square of the nozzle radius, making a 1.7 mm tip much faster at covering large surface areas.

Use this data to match your gun's output to the size of the project to ensure consistent film build.

Which common automotive or furniture finishes require a 1.7 mm tip for proper application?

Yes, high-build epoxy primers and thick polyester body fillers require a 1.7 mm tip to prevent nozzle blockage. These materials often feature a viscosity range of 25–40 seconds in a Zahn #2 cup, which is far too thick for the smaller 1.3 mm tips used for clear coats.

What maintenance steps are required to prevent clogging in larger-diameter spray tips?

Regular maintenance of a 1.7 mm tip involves clearing the fluid path immediately after use to prevent the thick coatings it handles from hardening inside the nozzle.

1. Flush the gun with the appropriate solvent immediately after spraying to remove residual solids.
2. Remove the air cap and soak it in a dedicated cleaning solution to dissolve buildup in the horn holes.
3. Use a soft nylon brush to clean the needle tip, as metal tools can scratch the precision-machined orifice.
4. Back-flush the fluid passage by blocking the nozzle with a gloved finger while pulling the trigger to force solvent through the internal channels.
5. Apply a drop of non-silicone gun lubricant to the needle spring to ensure smooth operation during future sessions.