Tried & tested
Mirka rotary sander reviewed plus some winter protection wash
Iwas in the gent’s at the boatyard, when I turned around and saw a proper weirdo staring right back at me – in the mirror. I’d been to the land beyond Middle Earth which I affectionately know as FAT (Flipping Antifouling Time – or something like that.) In the land of FAT tools need counseling afterwards and bodies contort so inhumanely that some of a certain age may take weeks to recover. That face of mine had a spotted mask of red and black with a bleached white line at the forehead. The hair looked like I had been sleeping rough and there was grime etched into the rough stubble. Not at all nice.
Less dust?
Having taken in some carbs and a coffee, it was time to make that tool scream again. The tool was the Mirka Deros 5650CV Random Orbital Sander which has been designed to offer dust-free sanding. From the look of my face after a couple of hours it’s just as well I was wearing protective glasses and a mask.
To be fair to the tool though, removing antifouling is not like any other job. A lot of the time I was lying on my back so some blow-back and fall-out was inevitable. The manual recommends that the tool ‘can be used in any position but before any such use, the operator must be in a secure position having a firm grip and footing...’ So on this job it was getting more abuse than normal, but overall sanding was less dusty than it would normally be.
The sander uses Abranet sanding discs made of an abrasive mesh with thousands of small holes that a vacuum system can suck the dust through.
This particular sander is advertised with the Mirka Dust Extractor but you can use any suitable vacuum system (check if you need hose adapters). In this case I linked it up to my own Bosch GAS 25 unit.
The 350W sander runs at speeds of 4,000-10,000rpm. It has an on/off button and an LED light shows green when it’s ready to go, but to actually start it you hold down a sprung lever – it then cuts out when you let go. This seems a clever idea and fine in a normal working position, but when shifting around under the hull I did find I’d inadvertently put the machine down on its back and so it would start up automatically. Speed is varied by pressing plus and minus buttons – a two-handed job when the machine in running.
Weight and noise
At 1.05kg the light weight made it easier on the arms than other sanders.
I did find the tone of it quite noisy, though. Sound emissions are given at 71dBA and on the lowest setting I measured it just under that at 67dBA. At the maximum power I was using it at, however, it was 91dBA – quite a bit noisier.
The tool also comes with a pad saver, a heavy duty flexible material a bit like a disc, but with Velcro on the back and front so goes over the fixed pad on the machine to protect it. The manual says this should be changed regularly and also points out the pad saver can increase the level of vibration. Hex nuts and screws are provided to be added to the armature inside the machine to reduce this. Either 150mm or 125mm pads can be fitted. Don’t lose the 24mm wrench provided to change pads – a normal spanner will be too thick to access the spindle nut.
As is always the case when dry sanding antifouling the abrasive sheets would clog up, the main reason why I often just wet sand antifouling by hand.
If you’re used to cutting your own abrasive sheets this is not a particularly cheap tool to run but Abranet aren’t normal discs. The recommended price for a pack of 10 is £19.85 and a pack of 50 is £62.20 for 80-grit or £54.40 for 120- and 240-grit.
The machine I was using has an RRP of £518.61, vacuum machines start at £386.66 and the extraction hose is £43.42.