Common Lacquer Spray Problems and Help
Common Spray Problems
Condition | Cause | Solution |
Heavy top or bottom pattern |
Horn holes plugged Obstruction on top of bottom of fluid tip Cap and/or tip seat dirty. |
Clean Clean. Ream with non-metallic point Clean |
Heavy right or |
Left or right side horn holes plugged. Dirt on left or right side of fluid tip. |
Clean. Ram with non-metallic point Clean |
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Remedies for the top-heavy, bottom-heavy and left-heavy patterns:
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Heavy center |
Fluid pressure too high for
atomization air (pressure feed). Material flow exceeds air cap's capacity. Spreader adjustment valve set too low. Atomizing pressure too low. Material too thick. |
Balance air and fluid pressure. Increase spray pattern width with spreader adjustment valve. Thin or lower fluid flow. Adjust. Increase pressure Thin to proper consistency. |
Split spray pattern |
Atomizing air pressure too high Fluid pressure too low (pressure feed only) Spreader adjusting valve set too high. |
Reduce at transformer or gun. Increase fluid pressure (increases gun handling speed). Adjust. |
Jerky or fluttering |
Loose or damaged fluid tip/seat. Material level too low. Container tipped too far. Obstruction in fluid passage. Loose or broken fluid tube or fluid inlet nipple. Dry or loose fluid needle packing nut. |
Tighten or replace. Refill Hold more upright Back flush with solvent. Tighten or replace. Lubricate or tighten. |
Unable to get round spray |
Spreader adjustment screw not
seated properly. Air cap retaking ring loose. |
Tighten or replace Tighten. |
Will not spray |
No air pressure at gun. Internal mix or pressure feed air cap and tip used with suction feed. Fluid pressure too low with internal mix cap and pressure tank. Fluid needle adjusting screw not open enough. Fluid too heavy for suction feed. |
Check air supply and air lines. Change to proper suction feed air cap and tip. Increase fluid pressure at tank. Open fluid needle adjusting screw. Thin material or change to pressure feed. |
Starved spray pattern |
Inadequate material flow. Low atomization air pressure (suction feed). |
Back fluid adjusting screw out to
first thread or increase fluid pressure at tank. Increase air pressure and rebalance gun. |
Excessive overspray |
Too much atomization air pressure. Gun too far from work surface Improper stroking (arcing, gun motion too fast) |
Reduce pressure. Adjust to proper distance. Move at moderate pace, parallel to work surface. |
Excessive fog |
Too much, or too fast-drying
thinner Too much atomization |
Remix properly. Reduce pressure |
Dry Spray |
Air Pressure too high. Gun tip too far from work surface. Gun motion too fast. Gun out of adjustment. |
Reduce air pressure. Adjust to proper distance, Slow down. Adjust. |
Fluid leaking from packing nut |
Packing nut loose. Packing worn or dry. |
Tighten, do not bind needle. Replace or lubricate. |
Fluid leaking or dripping from
front of pressure feed gun |
Packing nut too tight Dry packing. Fluid tip or needle worn or damage. Foreign matter in tip. Fluid needle spring broken Wrong size needle or tip. |
Adjust. Lubricate. Replace tip & needle with lapped sets. Clean. Replace. Replace. |
Runs and sags |
Too much material flow. Material too thin. Gun tilted on an angle, or gun motion too slow. |
Adjust gun or reduce fluid
pressure. Mix properly or apply light coats. Hold gun at right angle to work and adapt to proper gun technique. |
Thin, sandy coarse finish drying
before it flows out |
Gun too far from surface. Too much air pressure. Improper thinner being used. |
Check distance. Normally around
8". Reduce air pressure and check spray pattern. Follow paint manufacturer's mixing instructions. |
Thick, dimpled finish "orange peel" |
Gun too close to surface Air pressure too low. Improper thinner being used. Material not properly mixed. Surface rough, oily, dirty. |
Check distance. Normally about 8".
Too much material coarsely atomized. Increase air pressure or reduce fluid pressure. Follow paint manufacturer's mixing instructions. Follow paint manufacturer's mixing instructions. Properly clean and prepare. |
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