What is the difference between polishing and buffing?

Polishing uses abrasive belts or wheels to remove scratches and level the surface. Buffing uses soft mops and compounds to bring up the shine after polishing.

What Ra is needed for food-grade stainless steel?

Food and pharma equipment commonly asks for Ra 0.8 µm or better on product-contact surfaces, and Ra 0.4 µm or better for stricter hygienic uses. Check the customer's specification.

Can mild steel be mirror polished?

Yes, but it rusts quickly unless it is plated or coated. Mild steel is usually polished as preparation for chrome or nickel plating.

Polishing and buffing job work: finishes, Ra, uses

Polishing removes scratches and marks from a metal surface with abrasive belts, wheels or mops, working from coarse to fine grit. Buffing then brings up the shine with soft cloth mops and polishing compounds. Together they give finishes from a brushed satin to a mirror, mostly on stainless steel, brass, aluminium and chrome-plated parts.

Quick facts

Finishes: Satin / brushed, hairline, bright, mirror (No. 8)
Typical Ra: About 0.8 µm (satin) down to below 0.1 µm (mirror)
Materials: Stainless steel, brass, copper, aluminium, steel before plating
Methods: Belt, flap wheel, mop and compound; robot or manual
Food and pharma: Often specified by Ra, such as 0.4 or 0.8 µm max
Usually priced: Per piece or per square foot, by finish

How it is done

Weld beads and deep marks are ground flush first
Polishing with belts or flap wheels from coarse to fine grit (for example 80 → 400)
Buffing with sisal mops and cutting compound
Final buffing with soft cotton mops and a colour compound for mirror finish
Cleaning off compound residue, then passivation for stainless steel if needed

Common finishes

Finish	How it looks	Typical use
Satin / brushed	Fine straight lines, low shine	Panels, kitchen and pharma equipment
Hairline	Long continuous lines	Lift panels, architectural trim
Bright	Shiny, faint lines	Fittings, handles
Mirror	Reflects like a mirror	Decorative parts, moulds, rolls

What to tell the polishing shop

Material and the present condition (as rolled, machined, welded)
Finish required, by name or Ra value, and a sample if possible
Faces to polish and faces to leave
Direction of the grain for satin and hairline finishes
Whether weld seams must be blended invisible
Quantity, size and weight of the largest part

Need polishing and buffing done?

Post your requirement free. Workshops that take your kind of work see it and get in touch. You only talk to the ones that fit.

Get started

Related job work

Machines

TIG welding machine

Materials

Questions

What is the difference between polishing and buffing?: Polishing uses abrasive belts or wheels to remove scratches and level the surface. Buffing uses soft mops and compounds to bring up the shine after polishing.
What Ra is needed for food-grade stainless steel?: Food and pharma equipment commonly asks for Ra 0.8 µm or better on product-contact surfaces, and Ra 0.4 µm or better for stricter hygienic uses. Check the customer's specification.
Can mild steel be mirror polished?: Yes, but it rusts quickly unless it is plated or coated. Mild steel is usually polished as preparation for chrome or nickel plating.

The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 18 October 2026.