How to Grind Steel Fillet Weld With a Powerfile

Mig weld dressing handrails with a powerfile? Training at AFS today included abrasive belt weld grinding with the Beltit SH variable speed powerfile machine using ceramic abrasive belts. We were dressing a MIG weld on steel tubes and rails to prepare the welds for painting or powder coating.

Cibo FX87 80 grit ceramic powerfile belts

Typically a P80 grit belt finish would be ideal for painting over mild steel tubing. Therefore we selected the FX87 80 grit ceramic belt for dressing mig welds on the Beltit SH powerfile. Using the variable speed Beltit meant that we had greater control of the cutting speed and also of the finish we could achieve on the work piece. On mild steel the belts were run at 7,000rpm (approx 80% of maximum speed) which gave increased control of the belts and reduced the risk of the belts jumping and chewing the metal.

Typical mig weld on steel handrails & tubes

Working at 7,000rpm the 80 grit ceramic belt gives excellent aggression for the Beltit powerfile to dress out the mig weld quickly whilst leaving a finish that is consistent and fine enough for paint or powder coating.

Before, During & After sanding with FX87 80 grit ceramic powerfile belts

Hints and Tips:

To prevent chattering or gouging reduce the machine speed to ensure comfortable consistent working.
Use all of the belt to your advantage; work on the contact wheel for shaping and the slack of the belt for dressing and finishing the curved faces around the weld.
For most hand rail projects an 80 grit belt finish will give a very good quality finish, but if you need to go to a finer finish, use the medium surface conditioning belt after the FX87.
Note that if you vary the abrasive belt speed then you will also change the finish. For a coarser grit finish slow the powerfile down.

Take a look at how we got on below: