Metal finishing Q&As since 1989

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Stainless Steel Zinc Silicate Primers

Are Zinc Silicate Primers acceptable for first coating stainless steel enclosures?

Doug Gibson
eProduction Solutions Inc. - Kingwood, Texas
2002

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2002

Hi Doug,

We have done finishing of stainless steel(304 and 316) with a zinc-silicate on railway tankers where bimetallic couples were formed when joining the tank frame to the rolling chassis by welding. We blasted and coated both the carbon-steel and the first twelve inches in length of the stainless mounting brackets. This stopped any more bimetallic corrosion taking place. I would advise using only steel grit for the blasting, as it gives a guaranteed blast-profile (you need approximately 35/40 microns in depth: the coating goes on at 40/50 microns per coat). Other blast media shatters too easily on impact with the stainless and blunts the sharpness of the blast peaks.

Rick Simpson
- Irvine, Scotland