How Do I Achieve a 240 Grit Finish On Stainless Steel?

Why can nobody tell you what a 240 grit finish actually looks like?  Metal fabricators have for many years been frustrated when they receive their ‘finished’ stainless steel from their steel supplier. On both tube & flat stock the grain finish can vary widely.

Requesting a 240 grit finish has become a generic term for ‘a nice satin finish’, but how do I achieve it?  Below is a quick guide to the most common products we recommend to achieve a 240 grit satin finish on different metal surfaces.

How to Achieve a 240 grit Finish on Stainless Steel Handrails and Balustrading:

If joints are welded & you want a 240 grit finish then we strongly encourage the tig process which leaves a neat weld which can be ground away in one action with the RCD rapid combi flap disc.  RCD discs will leave a smooth finish without creating any flat spots on the tube.  That will leave a finish that just needs to be blended in with the original finish to leave the clean burr free finish your customers will love. The fastest way to achieve this is using the Cibo Finitube machine which will wrap up to 270 deg around the tube in one action.

We recommend a simple two stage belt sanding process:
Stage 1: Create a consistent grain finish with the new ceramic range FF87 P120 or P150 belts.  This will also remove any remaining damage and marks and create a consistent grain in the surface of the tube.

Stage 2: Blend the surface with the RC2 / medium surface conditioning belts.  a light dressing over the surface will remove any burrs and blend with the existing tube finish.

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How to Achieve a 240 grit Finish on Box Section Stainless Steel Tubes:

Often only 25 or 50mm wide the main need to re-finish this surface is where welding has occurred. Use our Time Saving Kit set 1 to remove the weld. This process will create a finish that is easy to re-brush working on the Finipower variable speed grinder.

Time Saving Kit: TSK/01 (see separate application guide for this process).  Kit 1 contains all you need to remove the weld and create a fine mitre cornered satin finish. The P100 ceramic discs remove the weld. Trizact discs are used in sequence to refine the finish. The final grain finish is put on with our FMCM combination flap brushes.

Working on larger quantities of box section? Consider the Garboli DUO machine which will process box section up to 150mm in width.

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How to Achieve a 240 grit Finish on Large Area Stainless Steel Sheet Panels (Hand Held Process):

Large stainless steel sheet sections are normally finished in the mill on continuous strip processes. These processes give a very consistent finish with a very short grain fleck in the surface. This can be very hard to match in a hand held operation. The ideal machine to use which will give the closest blend finish is the Finimaster Pro.  The PRO has a 5” inflatable wheel which makes it easy to create a consistent finish without chatter marks.

Coarser belt preparatory work may be necessary but for applying the final finish we recommend:

Stage 1 Re-creating the grain is best done with the Trizact 337DC A300 belts
(AFS part no: 337DC/A300/385X100)
Stage 2 Blend the surface finish with the FMTM 180 grit wheels to remove any edge lines
(AFS part no: FMTM/180/120110)

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How to Achieve a 240 grit Finish on Large Area Stainless Steel Sheet Panels (Free Standing Machine Process):

Ideally we recommend using a wide belt or a long belt / pad sander machine for grain finishing. There is a vast range of product options available dependent on the particular finish you are matching. Call to discuss if you are looking to engineer the correct process for this application.

For long grain finishing. Use our FX87 80 grit belts. For short grain finishes we recommend the A300, A160 or A65 Trizact belts.

Recommendation:  For complex profiles on a pad sander use the FF87 P80 grit semi flexible ceramic abrasive belts.  The high performance cut from the ceramic abrasive gives a great durability and excellent finish.