Airway vs. Sewn/Loose Buffing Wheels
Airway (ventilated, airflow, etc.) buffing wheels are a relatively recent industrial invention; however, due to their many advantages, traditional sewn and loose (full disc) buffing wheels have been supplanted in many processes.
At a glance, traditional buffing wheels are simply plys of cloth stacked and sewn together, whereas airway buffing wheels are typically built around a metal clinch ring. There is, however, more than meets the eye: perhaps the most significant difference between these types of buffing wheels is the process of "biasing". Before cloth is assembled into a buff, the fabric is first biased (slit and re-sewn) so that the woven threads are at a 45º angle to the periphery; each thread runs from the periphery of the buff through the clinch ring and back out to the periphery on the other side.
What advantages are gained by Bias/Airway Construction?
- Prolonged Life: bias construction prevents cross threads from pulling out, it reduces fraying and raveling, and creates less buffing dust debris.
- Finish Consistency: Traditional buffs fray unevenly, which can lead to strings sticking out; the plys are also more prone to spreading out, resulting in buff separation lines. Biased airway buffs' construction keeps the edge of the buff more consistent, and their plys tend to pucker and fold, resulting in a more uniform buffed surface.
- Compound Retention & Efficiency: because every thread runs to the face of the buff, the threads act like tiny brushes that retain and apply compound more effectively. In addition, the folds increase the surface area for compound retention, reducing buff wear and compound consumption.
- Ventilation: a constant stream of cool air is forced between buff sections for rapid heat dissipation, allowing higher buffing speeds, wider working faces, and cleaner/finer finishes with fewer passes.
- Compensating Density: hardness increases as buff diameter is reduced through wear, offsetting the reduced efficiency that normally takes place at lower surface speeds when conventional buffs are reduced in diameter. As a result, a more uniform rate of cutting and polishing is achieved throughout the buff's life.
- Width: airway buffing wheels are significantly wider than full disc buffs with the same number of plys, allowing you to buff a larger area at the same time
How is cutting action enhanced in airway vs. full disc buffs?
Traditional buffing wheels are primarily made more aggressive in two ways: treated material, and stitching.
- Cotton can be treated at a mill (mill treat) to enhance firmness, wear resistance, heat resistance, and (in some cases) compound retention.
- Stitching allows the plys of cloth to be held closer together, and helps the buff resist "mushing" when pressed firmly into a workpiece. As a result, more (tighter together) rows of stitching increase buff cutting action by forcing compound abrasives into the surface more aggressively.
- There are two methods: concentric and spiral sewn; of these, spiral sewing tends to produce more aggressive and consistently firm buffs. Concentric sewing get firmer as the buff wears closer to each row of stitching, and then looser when the stitching row falls out.
Airway buffing wheels, in contrast, are typically made more aggressive through treated material (mill treat and/or dip treat) as well as pack density.
- Pack relates to the size of drum used when forming an airway buffing wheel. A larger drum means that more material is "packed" into each ply of the buff.
- A "standard" 10" x 3" buff (#2, 16 ply) has roughly 34% more material in it than a 10", 40 ply full disc buff (you need about 54 plys to achieve the same amount of material)!
- You would need a 10" buff with more than 80 plys to have as much material as our Spectrum Custom Configured 10" x 3" (#2, 24 ply) untreated airways!
- More pack results in: more pleats, firmness (aggression), a harder buff face, and longer life.
What advantages do full disc buffs retain?
Although biased airway buffing wheels outperform full disc buffs in many ways, full disc construction retains some advantages:
- Balance: ultimately, when you force a lot of material into a small metal ring it can only bend and flex so much, and it doesn't always do so evenly. Even though Hilzinger takes special care manufacturing our buffs, the only way to guarantee no vibration is to test every buff off the line and toss the ones that don't pass - which would drastically increase the cost of the remaining "perfect" buffs. Full Discs buffs, in contrast, are just a series of sheets of cloth sewn together and as such are much less likely to feel imbalanced.
- Heat: Sometimes a little extra heat can be beneficial, although this carries some risks - especially on thin workpieces!
- Flexibility: stitching can be cut from sewn buffing wheels, allowing you to reduce their aggression on the fly.
- In addition, full disc buffing wheels can be worn down further and used in smaller spaces because there is no clinch ring to impede buffing
- e.g., a 10" full disc buff could be worn down nearly to the arbor hole, whereas a 10" x 3" airway could typically be used down to only 4.5" - 5" diameter.
- Although miniature airway buffing wheels are available, they cannot be made as small as full disc buffs due to their clinch rings, making them unsuitable for especially small areas or work pieces.
- Buffing Lines: because many full disc buffs are produced with untreated cotton and rely on stitching for aggression, they tend to leave a less aggressive finish even when cutting than treated cottons used in aggressive airway buffing wheels. This can also be advantageous on highly textured surfaces like diamond plate and step grating where untreated material "flows" more readily around obstacles than treated material.
- That said, untreated airway buffing wheels can also be stitched to add firmness but this represents an extra cost.
- Notably, in some instances a loose full-disc buff (fraying and buff face consistency notwithstanding) may finish more gently than an airway buff simply because they are less dense (and therefore, aggressive) by nature.
- Cost: full disc buffing wheels are typically cheaper to produce, so up-front costs can be lower. However, airway buffing wheels can (in many situations) produce results more efficiently, resulting in lower lifetime costs.
