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MG Chemicals 4228 – Red Insulating Varnish

4228 is a highly insulating coating with excellent arc and corona resistance. This red, low viscosity, one part varnish coating is easy to use and adheres well to many substrates. The 4228 insulates transformers, coils, motor windings, and various electric generator parts against arc and corona. As well, it protects these parts from corrosion and moisture.

Product Type: 1K (1 component) Coating, Coil Coating, Insulating Coating, Varnishes

Features: Corrosion Resistant, Durable, Ease of Handling, Excellent Moisture Resistance, Excellent Salt Spray Resistance, Excellent Substrate Adhesion, Flexible, Good Toughness, High Gloss, Low Viscosity, Oil Resistant, Water Resistant

Application Method: Brush, Dip Coating, Spray

Technical Data Sheet
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Knowde Enhanced TDS

Identification & Functionality

Features & Benefits

Key Attributes
  • Insulation Class H—Suitable for service up to 180 °C
  • Excellent oil and moisture resistant
  • Excellent finish—tough, flexible, glossy, and durable red coat
  • Good adhesion
  • Good water and salt water resistance
Brush
4226 can be applied by brush for rework or touch-ups. Thinning is not required for most brush applications. Desired coating thickness can be achieved in a single application. Applied coating can be cured immediately.

Applications & Uses

Application Method
Dip Coat

Due to the dual curing nature of this coating, it is important to control exposure to light and moisture to prevent premature curing.

  1. Hang the PCB on a dipping arm.
  2. Slowly lower the PCB into a tank and leave immersed in the coating for 2 min to allow penetration.
  3. Slowly withdraw the PCB from the tank at a rate of approximately 6" per minute.
  4. Applied coating can be cured immediately.
Manual Spray Guns

Use a standard fluid nozzle gun with a minimum tip diameter of 0.8–1.0 mm. The settings listed below are recommendations; however, performance will vary with different brands::

Inlet Air flow Air cap
20–40 psi 10–15 SCFM 8–10 psi
  1. Dilute 1-part coating to 1-part thinner (MG #4352 Thinner 2). Adjust ratio if required.
  2. Stir the coating gently, but thoroughly.
  3. Spray a test pattern to ensure good flow quality.
  4. Tilt the board at 45° and spray a thin even coat from a distance of 20–25 cm (8–10 in). Use spray-andrelease strokes with an even motion to avoid paint buildup in one spot. Start and end each stroke off the surface.
  5. Wait 5 min between coats to avoid trapping solvent.
  6. Rotate the board 90° and spray again to ensure good coverage.
  7. Apply additional coats until desired thickness is achieved (go to step 3).
  8. Let dry for 15 min at room temperature before applying heat cure. 
Recommended Preparation
Clean the substrate with Isopropyl Alcohol, MG #824, so the surface is free of oils, dust, and other residues.
Recommended Thinner
When thinning is required, use MG #4354 Thinner 4.

Properties

Physical Form
Typical Properties
ValueUnitsTest Method / Conditions
Density1.1g/mL
Theoretical Coverage at 25 mm890 000cm2/L
Viscosity (at 25˚C)590cP
Percent Solids52%
Cured Properties
ValueUnitsTest Method / Conditions
Minimum Recoat Time4
Service Temperature Range-40 to 180°C
Dry Time to Handle30minute
Dielectric Strength (wet)1 500V/mil
Recommended Film Thickness25-38μm
Dielectric Strength (dry)3 000V/mil
Uncured Properties
ValueUnitsTest Method / Conditions
Calculated VOC514g/L
Cure Instructions
Allow to dry at room temperature for 24 hours, or after letting sit for 30 minutes, cure the coating in an oven at 80 °C for 1 hour.

Regulatory & Compliance

Quality Standards

Technical Details & Test Data

Clean-up
Clean spray system and equipment with MEK or acetone, MG # 434.

Packaging & Availability

Packaging Type
Available Packaging
Cat. No. Packaging Net Volume Net Weight
4228-55ML Bottle 55 mL 58.3 g
4228-255ML Can 255 mL 238 g
4228-1L Can 850 mL 901 g
4228-4L Can 3.60 L 3.81 kg

Storage & Handling

Shelf Life
5 Years
Storage and Handling
Store between -5 and 25 ˚C in a in a dry area, away from sunlight (see SDS).