By John C. Harris
October 2010

At Chesapeake Light Craft, we build wood-epoxy boats for a living.  Wood-epoxy boatbuilding requires a lot of sanding.  A WHOLE lot of it.  Care and advanced technique can cut down on the worst of it, but we put in hundreds and hundreds of man-hours of sanding here.  Every day.  Feels like that, anyway.

So, sanders are important to the boatbuilders here.  We look for quality, power, ergonomics, and ease of attaching a vacuum hose.  We have another need:  endurance of abuse.  We teach at least two-dozen one-week boatbuilding classes each year, each corralling 6-10 boatbuilders all having at it with 5-inch random orbital sanders.  The sanders get dropped;  the operators push down too hard, frying the motors;  they use them with the sanding pad tilted up on edge until an instructor notices and raps the offender's knuckles;  and above all they operate for hours at a time in a swirl of epoxy dust, which works into the cooling vents and gradually clogs the machines, causing them to overheat or short out.  Switches break, wires wear out.

Thus we buy a lot of sanders.  I thought it would be helpful to review our collection of sanders NOT the way they do it in the glossy magazines, with shiny new machines sent fresh from the factory, but AFTER months and years of use and abuse.  What we do to these sanders is cruel and unusual, but it's also the real world.  Enjoy.

Some notes on the test subjects:

All of these sanders are the "random-orbital" variety.  This means that they do their cutting by spinning a disc and simultaneously vibrating it.  The "consumer" model sanders are all 5-inch;  2 out of the 3 of the "pro" models are 6-inch.  These are sizes suitable for folks who are building small wooden boats.

We use dust collection on our sanders 100% of the time.  To me, not connecting the hose from a powerful vacuum to the sander feels as awkward as getting in a car without buckling up.  It isn't just good for my lungs;  the dust evacuation helps keep the sandpaper from clogging up.  The consumer-type sanders all come with a tiny little collection baggie, and nearly all of them are useless.  Maybe they catch 30% of the dust, but it usually seems like less, and if you've got 20 hours of sanding to do, that 70% of the dust that goes airborne is enough to make you very, very unhappy.  After we throw away the stupid bag attachments, we use rubber adapters of various sizes, or sometimes just a ball of duct tape, to connect the hoses from our excellent Fein Turbo II wet-dry vacs. We have eight of those Fein vacs here, by the way, affectionately known as "R2 Units," and they are indispensable.  Quiet, astonishingly powerful, handy, and reliable.

We use "hook and loop" (velcro) sandpaper on all of our sanders.  It's just quick and easy, though the added expense compared to peel-and-stick paper is a drag.  The velcro pads wear out fairly quickly, and the manufacturers charge dearly for replacement pads, those knaves.

Note:  Since this is a review of used sanders instead of new ones, the exact model may no longer be made, though there is probably a close equivalent.

"Consumer Sanders"

Makita BO 5021

 $118, 2 amps

The most ergonomic sander I've ever held in my hands.  It's quiet and lightweight with little vibration.  At 2 amps, it's also the weakest one we have in the shop, and just barely strong enough for flattening big epoxy goobers.  The one in the photo is missing its pad, demonstrating a fairly common failure mode for random orbital sanders.  The sanding pad is secured to the motor's little transmission unit with three or four hex screws.  Since the sanders vibrate, the screws are set either in LocTite adhesive or the threads are slightly deformed so that they don't vibrate loose.  About half the time that the pads are replaced, the screws strip their threads or otherwise can't be caused to stay put, rendering the sander unusable without a repair costing as much as the unit itself.  That appears to be what befell our Makita BO 4021.  It is forever shelved.

DeWalt DW421

 $69, 2 amps

DeWalt was an early leader in an essential random orbital technology:  detecting whether or not you're pressing against the work when you turn it on.  Used to be, R/O sanders would spin up to 3000rpm the moment you turned them on unless you were pressing hard against the work to start with, and you would cut an awful scar in the side of your boat.  DeWalt developed a sort of clutch that sets the disc spinning only once you press down, and that's now a universal feature.  Note the square dust collection port missing its adaptor, which causes frustration when you want to fasten it to a round vacuum hose.  Remnants of tape attest to attempts to get sander and vacuum connected.  This one's power switch has failed, a very common malady in sanders, alas.  Often repairable with a screwdriver and a pair of pliers, sometimes the death of the machine.

DeWalt D26451

 $60, 3 amps

A more powerful and heavier-duty version of the lightweight DW421, yet it's cheaper.  This one has held up well;  it feels solid and the extra amp draw is welcome when it comes to cutting down thick epoxy.  The dust port adaptor will accept a variety of vacuum hose diameters.  Among the more ergonomic of the one-handed consumer types.  Don't discount the value of actual weight in a sander:  if it has some heft, that's a simple way to judge whether it's built strongly enough to survive being dropped.  And the extra mass cuts down on the vibration that tires your hands.

Porter Cable Model 333

 $N/A, 2.4 amps

This was, for about ten years, the stock CLC classroom sander.  We must have bought dozens of them.  They are big enough for all of the sanding you might encounter in a small wood-epoxy boat, and affordable at around $80 (certainly a major concern for us).  They are ergonomic and the vibration is manageable.  Over the years, they have not proven especially reliable, falling prey to loose wires, stripped screws on the sanding pads, dead switches, and tired-out motors.  Lightly built, they seem the most susceptible to death by dropping on a concrete floor.  Life expectancy in the CLC classrooms for these poor sanders was about 12 months.  The stripey thing is the end of what appears to be an entire roll of packing tape expended to make the dust collector hose stay put.

Porter Cable Model 343

 $50, 3 amps

Someone recommended these to replace our Porter Cable 333's, and they are showing promise after a year or two of hard duty.  Like the DeWalt D26451, they have some heft and a bit more power and the ergonomics are improved.  We've got two of them and they've been flogged through about 20 boats now, still going strong.  Seems great for the price.

"Pro Models"

Fein MSF 636-1

 $452, 3.6 amps

My personal favorite, requiring some care as I must hide it in a locker or have it nicked by jealous colleagues.  I bought this one in 2003 to restore a 26-foot sailboat, and it has survived some horrid projects since then with no sign of slowing down.  This German-made 6-inch random orbital demonstrates that you get what you pay for.  It cuts like a chainsaw if you need it to, but in certain circumstances it's delicate enough for 220-grit work.  Connected to a matching Fein Turbo II vac, there is NO dust.  Just none.  I sometimes wonder if it doesn't pull dust from other projects off the walls and floor, so effective is the dust collection.  It is also terribly noisy, and was from the moment it was new.  And the vibration is awful---more than an hour or two and your hands won't be the same for awhile.  It's heavy, so a two-handed grip (note the side handle) is needed.  You must buy special sandpaper with a hole pattern that matches its fancy dust-extracting pad.  So it's not perfect, but we're old friends, my Fein R/O and me, and we will be for a long time.

(Update, January 2016: I just used this sander all day in the shop today.  At age 13 the Fein still functions as if new.  It's been through countless replacement pads, and benefits from lubrication of the heavy-duty gearbox, but shows no signs of slowing down. Yes, it's still loud, but that's why they make hearing protectors.  I wear them.)

Festool RO 150 FEQ

 $495, 6 amps

My Fein's German competitor.  It's really just as good, and I've spent years attached to these as they are the stock sanders at the WoodenBoat School and at the Northwest Maritime Foundation.  I can't fall in love, however, because this sander and its vastly expensive vacuum attachment (shown in the photo) just feels over-invented, an industrial designer's injection-molded wet dream.  The sandpaper cost will stagger you. But it has loads of power, siphons up whole Saharas of dust, isn't as noisy or prone to vibration as the Fein, and it's more ergonomic.  Of course you can just connect the sander to a shop vac.

Bosch 3725 DVS

 $140, 3.3 amps

Our colleague Geoff Kerr threw this one into the ring.  He said it took ten years to wear his first one out.  It has most of the power of the Fein and Festool, but it's small enough to "one-hand."  In my judgment, this sander has most of the qualities of the uber-premium Fein and Festool, at a fraction of the cost.  Geoff claims its big filter attachment actually works, notwithstanding my incredulity about attached vacuum bags on R/O sanders. I'll plug it into my R2 unit, thank you.