For regional metal fabricators, machine shops, and OEMs, preparing parts for finishing requires planning for how those parts will hang, ground, and seal during application.
Proper racking point design and masking specifications speed up production turnarounds, lower finishing costs, and ensure critical mating surfaces remain clean of powder buildup.
1. Racking & Grounding: The Fundamentals
Electrostatic powder coating relies on a strong electrical ground. Electrons flow from the spray gun through the powder, attracting it to the grounded metal part hanging on the line.
-
Designate Dedicated Hanging Points: Ensure your parts have pre-drilled holes, internal tabs, or non-visual hook locations.
-
Maintain Metal-to-Metal Contact: The point where the hook touches the part must remain free of heavy scale or grease to maintain electrical continuity.
-
Evaluate Drainage & Air Traps: When parts travel through liquid pre-treatment washes or liquid immersion tanks, enclosed tubular weldments need drain holes to prevent solution entrapment and thermal blowouts in the cure oven.
2. High-Temperature Masking Best Practices
Because powder coating cures at temperatures ranging from 375°F to 400°F (190°C to 204°C), standard automotive masking tape or plastic plugs melt and ruin part finishes. Specialized high-temperature silicone and polyimide materials are required.
What Needs Masking:
-
Tapped Threaded Holes & Studs: Mating threads fill quickly with powder, leading to cross-threading during final assembly. High-temp silicone pull-plugs and push-caps preserve clean threads.
-
Grounding Planes & Electrical Contact Pads: Control panels, junction boxes, and transformer housings require unpainted metal contact pads for electrical grounding.
-
Precision Machined Bearing Bores: Tight-tolerance bearing seats and shaft interfaces cannot accommodate even 2–4 mils of powder thickness.
-
Mating Flanges & Weld Zones: Areas requiring secondary field welding or gasket sealing must remain bare.
3. Partnering with Your Finishing Specialist Early
Providing detailed blueprinted masking callouts prior to production prevents delays and rework.
At Premium Powder Coating in Longmont, CO, our team assists fabricators with custom silicone masking layouts and dedicated racking strategies. Contact our team today at quotes@premiumpowdercoating.com or call 303-776-7560 to discuss your project’s custom masking requirements.
