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  for Metal Finishing since 1989
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Cathodic "E" Coat painting

I am involved in maintaining a Cathodic "E" Coat painting process. Our plant is small and we are always looking at cutting costs. My question relates to the dilution of the drag-out tank. The accepted method of diluting this tank is the use of filters. These filters are very costly and the chemicals used to back flush the filters is very dangerous and costly. Have any of your members experimented with any other methods e.g. centrifuges etc? I would be very grateful for any ideas on this issue.

Best regards,

Peter Teague
- Pinetown, KwaZulu Natal, Republic of South Africa
2003

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Dear Peter: I do not know how small is small for you but we make E-coating system as small as 500 liters. We use spiral membranes. If your system is smaller than this, yes, UF can be said to be expensive. But for a well run 500 liter system, the UF cannot be termed as expensive. Normally acetic acid ⇦this on eBay or Amazon [affil links] or formic acid in very dilute form is used for cleaning of the UF. At that strength they are not very dangerous chemicals but they must always be discharged into an effluent treatment system.

adv.
If you want to discuss this in greater details, you can get in touch with me.

Gurvin Singh
Mohali, Punjab, India
2003

All the systems I have been involved with used ultra filtration, both cathodic and anodic. An automotive plant I was involved with also used reverse osmosis but in combination with UF.

Ronald Zeeman
- Brampton, ON, Canada
2003