Coatings & Inks

Powder Coating Batch Cost: Material, Labor, and Energy in One Calculation

Coating transfer efficiency is the percentage of material that actually lands on the part. Here is how to calculate it, what different application methods achieve, and how efficiency affects cost.

Transfer efficiency (TE) = (coating deposited on part / total coating consumed) x 100%. The balance (1 - TE) is overspray, drips, and evaporated solvent. Air spray guns: 25-40% TE. Airless spray: 40-65% TE. High-volume low-pressure (HVLP): 65-80% TE. Electrostatic spray: 70-85% TE. Dip/flow coating: 80-95% TE. Roll coating: 95-98% TE. The difference between a 35% TE air spray process and a 75% TE electrostatic process means you need 2.1x more material to deposit the same film weight.

Material cost impact: for a paint at $5.00/liter and a target DFT (dry film thickness) of 50 microns, theoretically required material = DFT/solids volume fraction. At 45% volume solids, wet film thickness required = 50/0.45 = 111 microns. Material needed per m^2 = 0.111 liters/m^2 at 100% TE. At 40% TE: actual material needed = 0.111/0.40 = 0.278 liters/m^2. At 75% TE: 0.148 liters/m^2. The difference: 0.130 liters/m^2 x $5.00 = $0.65/m^2 in additional material cost for the low-TE process.

Overspray waste also creates disposal cost. Solvent-borne overspray goes into the booth exhaust system and must be captured (filter pads, water wash, dry filter) for VOC compliance. Filter disposal and solvent waste disposal add cost. Switching to waterborne coatings or powder coatings eliminates most of this cost while often improving TE. VOC reduction and transfer efficiency improvement are often the same investment.

Electrostatic application improves TE by using electrical attraction to wrap coating around edges and onto difficult surfaces. The Faraday cage effect is the limitation: recessed or shielded areas are harder to coat electrostatically because the electric field is weaker there. Parts with deep pockets, tubes, or complex geometries may show lower TE in recessed areas even with electrostatic spray. Manual touch-up of problem areas is common but increases labor cost.

Measure actual TE on your specific parts and setup before specifying a new coating system. Advertised TE values are for flat panels under ideal conditions. Your complex shaped part in a real production environment will have lower TE. Test by weighing the part before and after coating and comparing to total material consumed. Run 10-20 parts to get a stable average. This measured TE is the input for accurate material cost calculation and financial justification of equipment upgrades.

Published 2026-05-28.