Sanding discs are part and parcel to metal polishing, but in many cases there are alternative tools that can reduce both your material consumption and time spent prepping a surface for polishing; that said, each one is best suited to particular jobs and has its own strengths and weaknesses. Both the abrasive type and structure of the buffing tool play a part in how aggressively the wheel behaves, so let's dive in!

Abrasive Types:

Bonded Abrasives

• Abrasive grains are bonded together into a solid form (often a wheel-shape); a binding agent or resin are used to reinforce the grinding surface while cutting.
• Best suited to aggressive cutting, grinding and stock removal. 
• E.g., grinding and cut-off wheels, mounted points, etc.

Coated Abrasives

• Abrasives grains are bonded to a backing surface, and an additional layer of binder supports the grains.
• Coated abrasives provide some of the cutting power of bonded abrasives but with the advantage of a flexible backing material for finishing; often used to refine grinding from bonded abrasives.
  
• E.g., vulcanized fiber/cloth/plastic film/paper-backed abrasive belts, sheets, discs, rolls, including fiber discs, sanding belts, sanding discs, etc.

Non-Woven Abrasives

• Abrasive grains are bonded via globules of resin to a web of nylon fibers; consistency is key when it comes to applying abrasive to the webbing as ideally fresh abrasive should be exposed as the webbing is worn down.
  • If abrasive grains are not distributed evenly, the material will not grind consistently and may have no abrasive grain in the interior layers of the webbing at all!
• Generally, non-woven abrasives are best suited to deburring, stripping, light weld removal, or satin finishing. They also resist loading (getting plugged up with removed material) especially well.
  • They are generally not well suited to serious stock removal and indeed are often desired where a surface must be finished without significant changes to the shape/dimensions of the workpiece.
• Webbing density and hardness can be modified to allow for a more aggression (and durability) or flexibility (for contoured or irregular workpieces).
  
• E,g, "Buff and Blend" discs, satin airways, non-woven hand pads (pot scrubbers), etc. Non-woven abrasive is an excellent alternative to bristle brushes, set-up wheels, greaseless compounds and steel wool.

Abrasive Tool Structure/Types:

Flap Wheels

• Flap wheels are normally used for parts whose contours are too difficult for abrasive belt grinding. Because the contact surface is on the outer end of the flaps, the intensity of grinding and resulting surface finish is uniform throughout the life of the tool - belts, in contrast, start sharp but lose their "bite" over time.
• Flap wheels are less aggressive than abrasive belts of the same grit; in other words, to achieve the same level of stock removal you would need a flap wheel with a grit 1-2 levels coarser than a flat abrasive belt.
• While flexible along the direction of buffing, flap wheels do not flex as easily side to side and are often trimmed to wide, square edges that can introduce grooving if not tapered.
• Miniature flap wheels and combination flap wheels are excellent for cleaning up and producing a brushed/satin finish in rim holes; miniature non-woven abrasive flap wheels produce a fine finish prior to polishing!
  

Coated Abrasive V-Fold Finger Buffing Wheel

• Officially designed for grinding of slots, grooves, counter-sunk areas and other narrow recesses, this buff provides more aggressive grinding than a strip-ring style abrasive buff due to it's multi-ply, wide fingers and folded structure. They excel at grinding rough surfaces without rounding nearby edges like diamond plate and step tops. 
• Significantly more flexible and dense than "pinwheel" style abrasive buffs which use a handful of wide strips.
• Because edges wear like a flap wheel, resists loading and cut behaviour remains consistent throughout lifespan.
• Finishes at a grit roughly 1.25x that of an equivalent sanding grit (e.g., 120 grit V-Fold finishes like a 150 grit sanding discs). Sanding grease (highly recommended) extends lifespan and allows the wheel to grind more smoothly and finish more gently.
  • Increase RPMs and use reduced pressure to grind more aggressively.
  • Reduce RPMs and use increased pressure to allow the strips to splay out and blend.

Excessive speed and pressure will cause premature wear of the wheel!

Try our new V-Fold Abrasive Finger buffing wheels today!

Sand-blasted diamond plate ground down with a V-Fold Coated Abrasive Buff + Sanding Grease, Softened with a Non-Woven Airway.

Coated Abrasive Strip Ring Airway Buffing Wheels

• Officially designed for deburring, edge rounding, and fine grinding of contoured parts, the strip ring abrasive buff grinds similarly to a flap wheel but allows for side-to-side flexibility due to the orientation and narrower width of the sanding belt strips.
  • Miniature 5" versions are also available for grinding operations on challenging pieces like cast turbo housings, etc.!
• Because edges wear like a flap wheel, resists loading and cut behaviour remains consistent throughout lifespan.
• Combines the fast cut of coated abrasives with the flexibility of a buffing wheel; especially useful for removing tar, adhesive, and silicone; removing Durabrite/Accushield coatings (even on mounted rims); and grinding down areas inaccessible to conventional sanding tools (drive wheel water channel, around back wall lug nuts, diamond plate, step grating, welds, cast aluminum, etc.)
  • Our prototypers even used the strip ring buff to sand (start to finish) relatively flat surfaces like fuel tanks, although found they got best results by ending with 600 grit on a sanding disc to ensure no linear textures in the finish.
• Finishes at a grit roughly 1.5x that of an equivalent sanding grit (e.g., 120 grit strip-ring finishes like a 180 grit sanding discs). Sanding grease (highly recommended) extends lifespan and allows the wheel to grind more smoothly and finish more gently.

• • Increase RPMs and use reduced pressure to grind more aggressively.
  • Reduce RPMs and use increased pressure to allow the strips to splay out and blend.
    

Excessive speed and pressure will cause premature wear of the wheel! Narrower strips like these can also shear when they catch edges, resulting in flying debris like with wire wheels - use caution and wear safety equipment.

Try our new Strip Ring Abrasive buffing wheels today!

Non-Woven Abrasive ("Buff & Blend") Discs

• Although frequently advertised as a "sanding replacement" (particularly on rim-polishing equipment), these discs have several characteristics that make them less suitable for grinding surfaces prior to polishing (in our opinion):
  • Typically very hard - limited flexibility (side-to-side when in a 2-ply configuration; at the face) can result in digging.
  • Hard, 90-degree edges can result in grooves in the finished surface.
  • Non-woven abrasives are less well-suited to stock removal and thus handle pitting less efficiently despite the aggressive characteristics of these discs.
  • More likely to have inconsistent abrasive grain dispersion than a coated abrasive - poor quality examples have too much grit in some areas and less in others, or may have little to no abrasive grain in the interior of the disc.
• They do have the advantage of being significantly more dense and durable than non-woven (satin) airways but are not well suited to finishing. As a result, like coated abrasive buffs they benefit from softening the finish with a satin airway but this cannot correct any grooves or dips imparted into the surface.
• Nylon is prone to melting when exposed to excessive RPM and heat, significantly reducing the lifespan and finish quality of non-woven abrasive buffs.

Non-Woven Abrasive (Satin) Airways

• Unfortunately, these buffing wheels are also frequently marketed as a sanding replacement. They are, however, even less aggressive and more fragile than non-woven discs.
• Non-Woven Airway buffs are designed for light to medium duty applications where coated abrasives are too aggressive or not applicable. The pleated design provides a more uniform finish than non-woven discs and help prevent rippling in your finish.
  • Used to produce decorative (satin) finishes, remove parting lines, for light deburring, breaking edges, sealer sanding, and rust removal.
  • Excellent for softening welds so polishing compound doesn't gather in the "dimes".
  • Excellent for softening the finish produced by coated abrasive buffs and non-woven discs.
  • We also recommend for at least a cleanup prior to polishing in areas where sanding is impractical, like the water channel in heavy truck drive rims.
    
• Their especially flexible nature means that these abrasive buffs produce a finish 1.5x-2x that of an equivalent sanding disc (e.g., a 180 grit non-woven airway produces a finish equivalent to 280 - 400 grit).
  • Sanding grease extends lifespan and allows the wheel to grind more smoothly and finish more gently.
• Nylon is prone to melting when exposed to excessive RPM and heat, significantly reducing the lifespan and finish quality of non-woven abrasive buffs. Especially rough or textured surfaces (e.g., step grating, diamond plating) can shred the webbing.
  

Try our Non-Woven Abrasive airway buffs today!

Conclusion

As with any buffing tool, each abrasive type and buff style has it's place in our work - but knowing how to choose the right ones - and the right supplier - makes all the difference.