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Will fume suppressants hurt bondability to chromic anodizing?

The EPA has mandated by regulation that all chromic acid anodize facilities reduce their chromium mist from the process by using chemical or mechanical means by January---. The least expensive method of compliance is by the use of fume suppressants to reduce the surface tension of the bath to at or below 45 dynes/cm. There seems to be limited data to determine if the use of surfactants, or suppressants contaminate the anodic surface for bonding and painting operations. Does anyone have any information as to what kind of surfactant to use and the effects of it as a contaminant?

Willard D. Sanders
1996

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Atotech is one of the largest suppliers of fume suppressants for this application; I think they can recommend some products and offer reassurances. You also might want to seriously consider attending AESF's Chromium Colloquium on May 30-31 in Cleveland (1996), which will be devoted in large measure to these MACT standards issues. You can contact AESF at www.namf.org to get a copy of the flyer. Even if you can't attend, the flyer will give you some idea who's doing what in this field so you know who it might be worthwhile to try to phone. Good luck!

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1996

We (Lockheed Martin Tactical Aircraft Systems) have performed qualification testing of anodized aluminum (anodized using mist suppressants) bonded to several different materials (paints, inks, graphite epoxy, various coatings). We have observed no adverse effects, in fact, some mechanical bond strengths are slightly higher. McDonnell Douglas has similar experience.

Scott Fetter
LMTAS - Fort Worth, Texas
1996

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While reading the EPA's handbook on how to comply with the chrome MACT, there was a note that the EPA was contemplating exempting both chromic anodizing and decorative chrome platers from the Title V permit requirements. This publication is some months (year?) old, and I am wondering if anyone knows if this did, or did not occur. Thanks

Brooke Warner
1996

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Hi, Brooke. Attending the AESF Chromium Symposium in Cleveland would be a wonderful idea for all. There you will find both the up-to-the-minute answer to this question, and the necessary background materials.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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Response to questions from Brooke Warner

EPA has exempted minor sources using Chromium anodizing or electroplating from the Title V permit, but this is only a temporary exemption and is subject to change in the next ten years if EPA wants to. A minor source is defined as a facility that emits less than 10 tons per year of any one HAP(chrome) or 25 tons per year total HAPs. Therefore, if your facility just does anodizing, you might not have to get a Title V permit.

Scott Fetter
LMTAS - Fort Worth, Texas
1996