Rotex PedigreeFestool makes more than a dozen power sanders that are highly competent in sanding for paint, carpentry and woodworking. Their flagship line of sanders is called Rotex, and the RO 90 is the third and most recent entry in that line. At 3½ inches in diameter, the RO 90 is smaller and more versatile than its Rotex siblings, the RO125 (5 inch) and the RO150 (6 inch), which have set benchmarks in sanding since the ’70s.Classic Rotex Sander Features
The RO 90 brings more sophisticated utility without compromising Rotex standards for power and performance.RO 90 – The Most Unique RotexThis is a Rotex platform scaled down to a 3½-inch diameter pad and with increased modal functionality – a robust little version of its larger siblings, with a twist.The three modes of RO 90 sander operation are:
A Review of the ModesRandom Orbital: The RO 90 is certainly competent as a finish sander in its random orbital mode. This is not where it excels though. If this were baseball, it would be like putting your shortstop at second base – its arm strength, range and athleticism overqualify it for the position. The RO 90 has a larger stroke than most dedicated orbital finish sanders, and its physical design makes it awkward for extended fine-finish sanding tasks because it is cumbersome to use with one hand. While capable in this mode, it causes user fatigue after a half hour or so. What it lacks in comparison to dedicated orbitals, it compensates for systemically through abrasive quality and dust extraction (which is phenomenal). This leaves you with an above-average finish sanding result, ideally suited to smaller-scale apps.Gear Driven (Rotex): The RO 90 is a beast in this mode, and this may be the biggest benefit for such a small sander to offer. The pad motion is eccentric in this mode, which in real terms translates to being very aggressive and capable of cleanly stripping an absurd number of layers of paint. This is where the RO 90’s design becomes a strength. It is built to be best operated with two hands, and with proper technique, it is easy to control during aggressive sanding for extended periods (hours).Technique is everything, and you may have to adjust yours to get along with this tool. If you try to fight this sander, you will probably lose. If you win, the results won’t be pretty anyway. So it is best to work “with” the sander. Proper technique includes a hand wrapped around the top front of the housing and a hand balancing it at the rear, near the cord. Front hand guides the sander, rear hand balances it laterally. This way, the pad stays flat on the surface being sanded, which results in best control, finish and dust extraction. The dust extraction in this mode is very impressive. This is the small belt sander effect you have been looking for.Triangular/Delta: The term “detail sander” needs to be understood here. This is not an intricate profile sander. The delta mode offers triangular attachments in different lengths to allow you to sand into corners and tight spaces and to reach into crevices with the same level of effectiveness as you would out in the open road with the stock round attachment in the other two modes. Delta mode eliminates hand sanding into awkward areas or having to break out a detail sander. The pad base swaps out quickly from round to triangle with no tools required – just the flip of a switch. In comparison to the other two modes, the dust extraction in delta mode is less effective because the sander is working in an orbital motion. With no spinning action, it is more difficult for the tool’s dust extractor to draw the dust. At the same time, dust mostly stays on the surface and does not become airborne. The RO 90 is capable of surprising aggression in this mode, making for seamless and quick transitions from open road into corners during sanding.Any “multi” tool has aspects of its skill set that are adequate but not stellar. It is not the job of the generalist to be perfect (that’s what specialists are for). It is the job of the generalist to deliver convenience and solutions to as many task challenges as possible.Practical Compromises in This Design
That said, there are work-arounds. The delta pads are symmetrical, so by rotating the abrasive orientation on the pad, all three points of the triangle can be used as the leading edge in sanding. This effectively triples abrasive life at the outer extremities but is still hard on the tips of the underlying base pad hook and loop. These slight drawbacks are a function of the literal strength of the sander: its power.Pound for pound, the RO 90 is arguably the most powerful Festool sander, capable of both detail and aggressive work. At 3.3 pounds, the RO 90 is less than a pound heavier than the smallest Festool orbital sanders (ETS 125/DTS 400/RTS 400). Th at is an engineering accomplishment, given how much is going on in the chassis of this tool. The power to size/weight ratio is hard to beat. In terms of sheer functionality, the only Festool sander that can match the RO 90 in flexibility and accessory options is their linear sander, the LS 130. Th at is where the similarities end. The LS 130 is a bit of a specialist, while the RO 90 is the ultimate generalist.Ultimate GeneralistHow has it taken so long for a manufacturer to realize the practical utility of a 3 ½-inch diameter sander?One of the most common sizes for dimension lumber in America is 1 inch by 4 inches (nominal), which is actually ¾ inch by 3½ inches. Historically, the most common size for random orbit sanders has been 5 inches – just a little large for a 1 by 4 and not quite ideal for larger widths like a 1 by 8, 10 or 12 inches. The RO 90 capitalizes on the reality that the world of wood finishing is full of square stock profiles that are 3 ½ inches or smaller. The RO 90 is ideal for those smaller dimensions and still has the power to get more aggressive than a traditional random orbital in widths larger than its own diameter. It is rare to find a sander that is so comfortable working on pieces that are both larger and smaller than the sander itself.With its small diameter, the RO 90’s wheelhouse includes but is certainly not limited to trim packs, cabinet face frames, furniture, stile- and rail-type cabinet doors/ drawers, spindle rail systems, clapboard reveals, and the endless inside corner and crevice work that have historically been a hand-sanding burden. Typical power sanders are not noted for this level of utility.It would be difficult to find one sander that is capable of accomplishing so many different types of tasks, particularly in the often extreme sanding discipline of low-grit paint stripping on exterior siding or trim. Teamed with CT dust extraction, the RO 90 works to a HEPA-certified standard, which takes some of the headache out of RRP work and keeps painters and jobsites running profoundly cleaner. This on-site efficiency usually translates well to profit margins on paper. As a generalist, the RO 90 touches on many of the basic competencies of other more specialized sanders, and Festool offers an abrasive grit range of 40-4000 across eight different lines of abrasive. For all painting tasks, I prefer their Granat line, which comes in grits ranging from 40-500. Granat routinely lasts three times as long as other abrasive brands I have used.The ModesOverall, we rate the three modes of the tool highly. Especially the gear-driven and delta modes, which exceed anything else we have seen. The random orbital mode, which is the easiest to compare with the rest of the sanding marketplace, produces a better-quality result than other brands of random orbitals we have used, perhaps due as much as anything to the systemic advantage of abrasive quality and premier dust extraction. But it is not as exceptional by Festool standards as are the other two modes – mostly for the ergonomic/balance reasons outlined above. In other words, finish sanding is less fatiguing with a true Festool orbital, which is typically expected to be a one-handed exercise with minimal vibration or physical exertion. The RO 90 can certainly deliver similar results, preferably just in shorter doses, which is perfectly acceptable in a multifunction convenience tool. If you don’t habitually sand for extended periods, it is a negligible concern.Final AnalysisAt $385, this is not an impulse buy. And it is not a disposable or throwaway tool. Having used Festool sanders, abrasives and vacs for 18 months now, and also having observed the corporate values that the tools are backed by, Festool is clearly interested in competing only with Festool. They are not concerned with making a better or cheaper tool than someone else but rather a more effective tool than they themselves have made before – measured by the tool’s capacity to provide efficient solutions to real problems.The RO 90 reflects this approach with unique strengths, features, functionality and ability to solve both typical and unusual problems for painters. Because the RO 90 is easy to use in so many different types of situations, it serves both beginner and advanced Festool users in a wide task range with industry-leading dust control. Like most Festool offerings, this tool works optimally as a system with a Festool vac and abrasives. FestoolUSA provides a legendary three year warranty and 30-day-no-questions return policy, so there is little risk involved in checking out their gear.No sander can be all things to all people, but the RO 90 stands a far better chance than most. If you are the type of person who does all kinds of sanding, this is all kinds of sander. APCScott Burt is the president of Topcoat Finishes, Inc., in Jericho, Vt. He enjoys communicating with contractors and manufacturers at topcoatreview.com.