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Is there a standard zinc dichromate coating repair procedure?

2007

We are currently using a zinc dichromate coating on a mild steel tube per ASTM A513, Grade 1010, but suffering from customer complaints of cosmetic issues from installation.

Zinc dichromate plating per ASTM B633 FE/ZN 12, service condition SC3.

Is there a standard that can be applied in the repair of localized areas of the coating, to attain the original intended protection of the base material?

At the moment, we are having to field replace entire members due to this issue.

William Goodson
Product Designer - Minneapolis, Minnesota, USA

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2007

Mr. Goodson,

I am not aware of any standard. Nevertheless, you can apply brush plating to the area needed; only if it is clear (blue) chromate. Yet would look somehow like a patch. If it is only a cosmetic problem and is only in some localized areas, you can apply the brush plating to give the corrosion protection and then add some powder metallic paint that would disguise the patch. The extreme case would be removing the pipe and get it plated again.

Saludos.

Guillermo Castorena G.
Jobshop - San Luis Potosí, México

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Sometimes you can apply a chromate touch up, but most of the time it will be a little ugly to really ugly.
Normally, a brush plate repair will be ugly!

James Watts
- Navarre, Florida
2007