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Poor paint adhesion on shocks

 

Dear Prof,

Please note that we are shock absorber manufacturer in India using autophoretic paint process to paint the cold drawn steel tubes of dia meter 45~56 mm. the part length varies between 300 mm to 600mm. We do not use any derust process online as this gives problem of poor paint quality and faster depletion of paint bath due to addition of Iron.We are facing the problem of poor paint adhesion on the bigger parts.our temp range is 110~125°C. Please advice us what all precautions should we take further?

Ajay Aryavir
- Noida, UP, INDIA

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Dear Sir,

Please be advised that my company supplies ACC to a number of shock absorber lines in Europe. These lines all have on line pickling to clean up the carbonised areas on and around the welds. These perform very well for corrosion performance, not only on the main body of the shock absorber but also on weld areas. What is important is to chose a low smutting acid and to follow the acid pickle with an alkali desmut, preferably by spray. Very high performance can be achieved in this way on fully assembled shock absorbers.

Andy Thomas
- Milton Keynes, Berks, UK