Comparing orbital and rotary polishing machines

Rotary sander-polishers are great general purpose machines, well suited to repair work, sanding, and compounding. They are the workhorse of a repair yard, but not the best for regular polishing.

Orbital polishers are specialised for finish polishing. They can do this far more efficiently than a rotary machine as they have a larger head and can't overheat the surface. Here's why:

Orbital polisher

Best for polishing and buffing
Covers large areas very fast
Won't overheat gel coat or leave 'comet tails'

Multi-purpose machine
Great for repairs and preparation
High speed must be used with care

Rotary action

With a rotating disc, the outside edge moves much faster over the surface than the centre. The outer section of the disc does most of the work, with the centre doing practically nothing.

To cover large areas quickly, a machine needs a large head, but the larger the head, the greater the peripheral speed of the disc. In practice, 180mm (7 inch) is the maximum for hand-held rotary machines.

When using a sander-polisher, it's tempting to wind up the speed, but this can overheat the edge, leaving comet tails or permanently damaging the gel coat. For fibreglass, we suggest a maximum of 600 - 1000 rpm, and when a rotary machine is used for polishing, we recommend the use of a soft foam pad.

Orbital action

For polishing, the ideal action is like the movement of a hand with the whole pad moving at the same speed in small orbits. A machine with this action has no hot spots or cold spots and can have a much bigger pad than a rotary machine with no danger of overheating. An orbital pad 275mm (11 inch) diameter is more than double the surface area of a 7 inch one.

All of this means that an efficient orbital polisher can buff the topsides of a boat in minutes, and makes it practical to maintain a brilliant shine on larger vessels. The hand-like action is easily controlled, can't damage the surface and won't run away from the operator.

For routine polishing and maintenance, an orbital polisher can easily pay for itself on the first few jobs.

Ideal machines

See our range of sander-polishers here or orbital polishers here