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Cloudy zinc, after heat is applied

We are experiencing cloudy streaks after we have put zinc plated parts through our bake oven, has anyone had similar problems with clear zinc ? and does anyone have suggestions on how to fix this.

Julie Labelle
sheet metal fabrication - Canada
2006

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It is generally the practice to bake then chromate unless you are using a chromate specifically formulated to allow baking. Some people believe that they are able to bake after chromating because they have done it. This may be true but a loss of corrosion protection would probably be occurring.

I think what you may have is a heavier than normal chromate film (if you have been baking without problems before) or poor rinsing. It can also be excess organics from high brightener components in the zinc bath. In any of these cases you should be able to reactivate the zinc and re-chromate

Gene Packman
process supplier - Great Neck, New York
2006

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Hi Julie Labelle,
May I know why is this being done. Is it for drying, or for annealing or for Hydrogen de-embrittlement. In either of these cases basically a different drying process may be required at least to an extent where there is no dripping of fluids exist from component. You have not mentioned the structure or geography of the part which is very critical for the problem you are facing.

Sanjeeva
Supply Chain - Bangalore, India
2006