Bosch GEX 18V-125 Review: A Cordless Random Orbit Sander With a Low-Profile Design That Just Feels Right

Introduction

When rough plywood needs to go on a ceiling, a decent sander stops being a nice-to-have. That was the situation that led to picking up the Bosch Professional Blue 18V cordless random orbit sander kit, model GEX 18V-125, and putting it to work on plywood lining, window frames, and some seriously tired decking timber. After several weeks of regular use, it has earned a clear verdict, and it is a positive one.

The kit bundles the sander with a 4Ah battery and the GAL 18V-40 charger, with the tool itself packed in a L-BOXX-style case. Here is how it performed, and why a set of mesh sanding discs turned out to be an unexpected highlight of the project.

First Impressions and Design

Straight out of the box, the low-profile shape is the thing you notice. The palm-grip body sits low over the pad, with a rounded rear that fits the hand almost perfectly. Compared side by side with a taller Makita equivalent, the difference in ergonomics is immediate: the Bosch feels better balanced and noticeably more comfortable to hold, especially when pressing directly down onto the pad as you sand.

With the included 4Ah battery fitted, the weight feels well judged. Step up to a bigger 8Ah ProCORE pack and the balance shifts rear-heavy, though it still does not feel awkward in the hand. That said, the 4Ah pack that comes in the kit is the sensible default for this tool.

The power button sits right where your hand naturally rests, and speed control is variable: level 1 runs at 6,000 RPM and level 6 at 10,000 RPM. Another pleasant surprise is the sound. It is a nice, quiet tool compared to many sanders, which you will appreciate during long sessions indoors.

Dust Collection and Extraction

In the box you get a dust bag that hooks onto the side port. It is a spongy fabric bag that attaches securely, though getting it on one-handed takes a bit of fiddling. The port is on a swivelling outlet, so you can angle it out of the way, and a wet/dry vac hose adapter fits over it snugly. The ribbed port grips the adapter tightly enough that it will not pop off mid-task.

Connected to a vacuum, the extraction is genuinely impressive. Even at half power on a workshop vac, dust pickup is strong; on full power it is, frankly, very sucky. Sanding printed ink off the back of plywood sheets came off clean with barely any dust escaping, and the results were consistent across plywood, primed timber, and hardwood decking boards.

Diablo SandNet Discs: A Different Approach

Alongside the sander, it is worth talking about the Diablo SandNet discs, because they change how the tool behaves. Instead of a conventional coated abrasive disc, SandNet is an open mesh: you can see straight through it. The claim is up to ten times longer life than standard discs, and in practice they resist clogging well, since dust pulls through the mesh rather than building up on the surface.

They come with a sacrificial backing pad you stick on first, which protects your sander’s hook-and-loop pad from filling with dust through the mesh. The pads stick on securely, though the hole pattern does not line up neatly with the sander’s pad holes, which looks odd at first but makes no difference in use.

Even a fine 220-grit SandNet disc removed material surprisingly fast, gliding over pre-primed timber and old Vitex decking boards without clogging. They are available from 60 grit up to 400 grit, so there is a full range for everything from aggressive cleanup to final finishing. If a disc does pick up debris, the flexible mesh makes it easy to knock loose.

Head-to-Head With a Makita

To make things fair, the Bosch went up against a Makita random orbit sander with a 120-grit pad on each, sanding opposite halves of the same rough hardwood board with no dust extraction attached, both running at top speed.

The material removal rates were close to identical, and both felt similar in cutting power. The differences showed up elsewhere. The Bosch stops almost instantly when switched off, while the Makita coasts down slowly. Under heavy pressure, neither sander stalled easily: even with full body weight on the Bosch, it refused to cut out, and the test was ended more to protect the tool than because the motor gave up.

The deciding factor, once again, is the ergonomics. The Bosch’s low, rounded body is simply nicer to hold over a long session, closer in feel to a pneumatic sander than the taller designs from Makita, Hikoki, Milwaukee, Ryobi, or AEG. It does stick out a little more than some rivals, and the side-mounted extraction port can sit slightly in the way, but the swivel outlet makes that easy to manage.

Things to Consider Before Buying

The kit ships with a single sheet of 120-grit paper, a dust bag, the tool, a 4Ah battery, and a charger. If you plan serious sanding, budget for extra abrasives up front, and consider whether you already own Bosch 18V batteries to keep costs down. With the largest ProCORE packs the balance tips rear-heavy, so the lighter 4Ah pack remains the best match for overhead or one-handed work.

Buying Advice

If your sanding involves long sessions, plywood lining, window frames, or decking refresh work, the GEX 18V-125 is an easy recommendation. Its standout qualities are the genuinely low-profile grip, quick motor braking, strong dust extraction when paired with a vac, and quiet operation. Pair it with Diablo SandNet mesh discs, particularly around 120 grit for general work, and the whole setup punches well above its weight.

Conclusion

After weeks of plywood, primed timber, and weathered decking, this Bosch has become a firm favourite, preferred over a comparable Makita mostly on the strength of its comfort and control. Combined with mesh SandNet discs that resist clogging and cut fast even in fine grits, it makes a repetitive job noticeably more pleasant. For anyone building out a Bosch 18V collection, it slots in as a genuinely useful addition.