Topic: How can I achieve a mirror finish on Cast Iron

Hi all

I’m in a real pickle and i hope someone can help me .I deal in Cast Iron Bath Tubs and the latest thing is to
have the exterior of the tub polished to a mirror finish.
I have tried endlessly to achieve this but can’t get it
right .
I know it can be done (see pic ) but I must be missing
something in the process .
If someone could help with a step by step guide it would be
much appreciated and i will post the results


  polished bath.jpg


Re: How can I achieve a mirror finish on Cast Iron

Are you sure that the tub in the picture is not plated? How do they keep the cast iron from oxidizing?

I've never worked with cast iron before (other than my personal cookware), but the usual process for something like this would go as follows:

grind/sand with a ~80-120 grit compound or wheel

sand further with a ~300 grit compound or wheel

Polish with a tripoli-type (brown) compound

Polish with a green compound (I forget the industry term)

Buff with a white compound (I forget the industry term again)

At this stage, parts are usually ready for decorative plating. I'm not sure how cast iron would look. I wonder if there is a electropolish or chemical polish that would work in this case? If so, you'd still want to take it to at least the green compound stage.

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer


Sanford, NC


Re: How can I achieve a mirror finish on Cast Iron

Ultrasonic Impact Treatment Equipment is a method to turn welding residual stress into compressive stress. (various kinds of methods of relieving residual stress are as below: Vibratory Stress Relief 3055, Thermal Aging 4080%, Ultrasonic Impact Aging 80100).

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