How to Mirror Polish Stainless Steel Fillet Welds

Creating a mirror polish finish can be particularly time consuming, especially when perfecting stainless steel fillet welds in tube joints and box sections.

Save time by following Cibo’s simplified process;

Time Saving Kit 05 provides all of the essential abrasive products you need to create a high-shine mirror polish in a fraction of the time.

What are Time Saving Kits?

A Cibo Time Saving Kit contains all the products and information you need to complete your desired process. There are 3 kits for satin finishing and 3 for mirror polishing. See all kits here.

Process Overview

Sand down the welded joints using Cibo’s unitised discs.

Coat the felt disc in pink polishing compound and use to polish your workpiece.

Clean up using and remove residue using vienna chalk.

Read on for helpful tips and in-depth information regarding the TSK05 process. All of the below steps can be followed when working on both inner box and inner tube sections.

Step 1: Preparation

Firstly, attach the MA/8/T30 unitised disc to your Finit-Easy machine and set to 3000 RPM.

Dress the new unitised sanding disc against an abrasive file with attached grip strip before first use. This allows the three dimensional abrasive structure to be used at it’s optimum ability.

Abrasive tip: To avoid the Finit Easy protective guard from preventing you reaching the inner corner  of your workpiece, use a click and slide movement to lock it into a suitable position.

Step 2: Sanding The Welds

Using the MA/8/T30 disc, sand down the welded joint in the direction of the final finish. Continue until the stainless steel is smooth and the joint is no longer visible.

Replace your current unitised disc with SA/5/T31. By moving this disc along the weld, you can blend the sanding pattern left by the MA/8 disc.

To remove the weld discolouration, move the SA/5 disc away from the inner corner and back again. The flexibility of the disc reduces the risk of undercutting during this step.

Once satisfied with this result, repeat the process on the opposite side of the inner joint.

Step 3: Perfecting The Mirror Polish

Attach the MHV5600/T31 felt disc on to your Finit-Easy machine. The optimum grinding speed for this step is around 2000 RPM.

Hold the disc against the PV/102 pink polishing compound and let it rotate until the edge of the disc is coated in polish.

Move the felt disc over the welded joint in a backwards-forwards motion to the edge of your workpiece until you are happy with the result.

Step 4: Cleaning Up

Easily remove any residue left by the polishing compound by using a sprinkling of PV/103 vienna chalk in combination with a soft microfibre cloth.

The chalk will de-grease your workpiece and unveil the mirror polish finish without scratching your workpiece.

What is Included in Time Saving Kit 05?

All of the essential products you need for the mirror polish process are inside the box;

• MA/8/T30   (x2 Discs) Unitised discs in grade 8 measuring 150mm x 3mm x25.4mm to sand down the welded joint.
• SA/5/T31   (x2 Discs) Unitised discs in grade 5 measuring 150mm x 6mm x 25.4mm to blend the finish left by the previous abrasive disc.
• MHV/5600/T31  (x1 Disc) 150mm diameter flexible disc made from high density felt for polishing.
• PV/102 (x1 300g Bar) Pink polishing compound for a bright, highly reflective finish.
• PV/103  (x1 150g Tub) Vienna chalk to remove polishing compound residue and leave the surface grease-free.

The following extras are not in the kit, but we do recommend them in order to take the quality of the finish a step further;

SV/19030  Velcro-faced hand dressing file with grip fixing for abrasive strips.

706GR/24/V006  (Available in packs of 25) Silicone Carbide 24 grit grip strips for use with the abrasive file.

SMFEMA Finiteasy Cibo’s hand-held fillet weld grinding machine, essential for completing this process.

Please take a look at our short video below to see brief clips of the above steps