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Preparation of mild steel

 

Could someone please tell me a good way to prepare mild steel before I paint or powder coat. I need to find out the best way ( or a good way) to finish an out side fence and railing. Had a sample part powder coated (mild steel)but when it returned I could see all the uneven scale on the metal. I was told not to break the mill finish but when we bend the mild steel the finish cracks also the finish is not always the best from the suppliers( can't send it like that). The next sample I tried to blend the broken surfaces but that will take a long time with big jobs (still haven't got it back). I want to do quality work, but I am very new to the trade and to this great site. Sorry if this sounds like a stupid question but I could really use the help.

I would also like to thank everyone who help with my stainless question.

Jason Ashfield
Jayco - Niagara Falls, Ont. Canada

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If it's not prohibitively expensive, sand blasting will get rid of the scale and give you a stable starting point. If you see rough non-adherent mill scale and it is not removed, and you are going to later bend it, a stable finish is simply not possible. Ideally you should do an iron phosphate after the sandblasting, but lack of phosphatizing does not seem to be the weak link here.

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