How to Mirror Polish Stainless Steel Mitre Corners

The process of producing a bright mirror polish can be extremely time consuming, especially on stainless steel mitre corners.

Cibo have taken away the need for this long and laborious process with their innovative Time Saving Kit 04.

Now you can achieve a high-shine mirror polish in just minutes.

Let’s talk through the step-by-step process…

Process Overview

Prepare your mitre corner point using our RCD flap disc.

Sand the joint with LCGR discs, refining with 237GR discs.

Pre polish with our unitised SAGR disc.

Polish with felt and our green polishing compound.

Apply Inoxitape and polish with soft flannel polishing wheel and our pink polishing compound.

Remove polishing residue with vienna chalk.

Continue reading our in-depth guide below…

Step 1: Preparation

Quick Change Grip Disc satin finishing metal

In order to prepare the stainless steel corner for the polishing process, use the RCD/ME/125 flap disc with an your angle grinder set between 3000-4000 RPM. Run the disc along the outer corners until smooth.

Abrasive tip: When using a new Rapid Combi Disc, firstly dress the grit on a test piece to avoid the harshness of an unused disc on your workpiece.

Now attach the 125VEL/VZ flexible back up pad to your variable speed angle grinder. Cibo’s Finipower machine is the perfect tool for this process.

Next, secure the 125IT heat-resistant interface foam to the velcro back up pad – this reduces grinding pressure and increases control so you can remove the weld without the risk of undercutting.

How To Mirror Polish Mitres and Outer Box Sections - Step 1: Preparation

Step 2: Dressing the welds

Simply attach the FX87GR/100/S133 ceramic sanding disc to the interface foam and sand the welded joint flat. Your angle grinder’s optimum rotation speed for this is between 3,000 and 4,000 RPM.

After this step, you may notice grinding lines on the surface of the stainless steel. Don’t worry – you can remove these easily; start with the coarsest Trizact grip disc 237GR/A160/S133 and blend the 100 grit sanding lines until smooth.

Then repeat with 237GR/A65/S133 followed by 237GR/A30/S133 for an enhanced result. This will leave a 280 grit finish on your workpiece.

Once you are satisfied with this result, allow your workpiece to cool.

Abrasive Tip: Use your air tool to speed up the cooling process.

How To Mirror Polish Mitres and Outer Box Sections - Step 2: Dressing the welds

Step 3: Pre-polishing

After the grinding lines and scratches have been removed with the Trizact grip discs, move on to the SAGR/5/S105 unitised disc and affix to the back up pad.

Use this disc in a perpendicular direction to the one followed in the previous step.

Next, use 237GR/A6/S133 to ensure even the finest of grinding lines are erased in preparation for the final mirror polish.

Abrasive Tip: Once the outer edge of your sanding disc is used up, push out the inner circle for a new 75mm disc. This can be used with the 75mm backing pad and interface foam to ensure maximum usage.

How To Mirror Polish Mitres and Outer Box Sections - Step 3: Pre-polishing

Step 4: Polishing with felt

For the next step, attach the felt V/H/S109 grip disc to your angle grinder.

Before use, allow the disc to rotate at a speed of 3000 to 4000 RPM, then, take the green PV/101 polishing bar and hold against the felt disc, coating it in a layer of the compound.

Using the same speed setting, begin to polish the stainless steel. Do this until you obtain a smooth surface.

Step 5: Final Polishing with flannel

Polishing Wheel on Finimaster Drum Sander

The circular motion of the felt disc used in the previous step will have left the direction of the polish visible. To amend this, use the FLM/12550 mop wheel.

Cover the mop in pink PV/102 polishing compound by holding the bar against the wheel with your machine set at a slower speed of 2000 RPM.

MHIT Inoxitape is vital for a precise mitre corner on your stainless steel. You can grab a roll of this here. If you are aiming for a smooth mirror polish without a corner line, skip this step.

Remove the adhesive strip. Attach this to your workpiece from the inner to the outer corner.

Polish the surface lengthwise towards the inoxitape, remaining on the side of the tape you are currently working on.

The polish on the mop will begin to turn black as you move it along the stainless steel. Keep up this motion and repeat on the opposite side of the Inoxitape until you achieve a super bright mirror polish on your metal.