VpCI™-374 on ADC Brackets
Background: ADC has brackets that fasten electronic equipment to outdoor surfaces. These brackets are currently coated with a Sherwin Williams (S/W) solvent-based product. These brackets are corroding prematurely. ADC wishes to get five years corrosion protection from their brackets. They are looking into a hot dipped galvanized method but would prefer to go with an environmentally friendly method. ADC also has several hundred brackets (coated with S/W paint, in inventory) that need additional corrosion protection to be field ready.
1) Determine salt spray protection of various coatings on brackets provided by ADC.
2) Determine if VpCI™-374 can be top coated over Sherwin Williams paint to improve corrosion protection.
Materials: VpCI™-374 primer
VpCI™-432 paint stripper
3x5 inch brushed carbon steel "Q" panels
Elektro-Physik N Koln Minitester 500 Thickness Gauge
Adhesion testing tape "Permacel"
Method: Salt spray Chamber (ASTM B-117)
Tape Pull-Off Adhesion Test (ASTM D-3359)
Coating (BRACKETS) Thickness (DFT)* Salt spray (Hours)
Sherwin Williams (SW) 0.8 to 1.5 mils 270
SW/VpCI™-374 4.0 to 6.0 mils 674
VpCI™-374 2.8 to 5.0 mils 840
Galvanized 4.0 to 6.0 mils 840
Coating ("Q" panels) Thickness (DFT)* Salt spray (960 Hours)
VpCI™-374 2.0 to 2.0 mils PASS
SW 2.0 to 2.1 mils FAIL
Tape Pull-Off Adhesion Test on brackets (S/W top coated with VpCI™-374).
5-B = best adhesion and 0-B = worst adhesion.
With VpCI™-414 cleaning (5-B to 4-B) PASS
Without cleaning (1-B to 0-B) FAIL
*Dry Film Thickness (DFT) was measured in mils (1 mil = 1/1,000 of an inch and 1 mil = 25 microns).
Project #: 01-257-1525
Time Spent on Project: 16 Hours
To: Richard Atlas/AEI
From: Luc Butzon
cc: Boris Miksic
960 Hours Salt Spray
No pre-cleaning. Poor adhesion of VpCI™-374 to Sherwin Williams Coating
Pre-cleaning with VpCI™-414 at 10%, water rinse, dry. Sherwin Williams top coated with VpCI™-374. Excellent adhesion.