The New Bosch GMS120 Wall Scanner features Multi-Mode Detection-For wood studs, metal objects (rebar, studs and steel/copper pipes) and live wiring. Illuminated Graphical LCD Display-Indicates mode, detection strength and more. Deep Metal Detection Capability-Detects steel up to 4-3/4 in. (120 mm) deep in cured concrete. Automatic Center Finder-For locating center of detected wood or metal object. 3 Selection Modes (Wood, Metal, AC Wiring) with automatic calibration for easy and precise detection. Audible Detection Signal-With On/Off button. Ergonomic Soft-Grip-For secure grip and comfort. Illuminated ring indicates detection status.
(52 reviews) 52
74%of customersrecommend this product37 of 50reviews
Rating Breakdown52 reviews
74%of customersrecommend this product37 of 50reviews
I was frustrated buying cheap, throw-away stud finders that never seem to work when you need one, so I stepped up to the Bosch GMS120 Professional Wall Scanner. It comes with a nice flexible storage case with hand lanyard and belt loop. Using this wall scanner is not intuitive and requires reading the instructions thoroughly. There are multi-colored flashing lights, changing bar graphs, symbols and sounds that requires prior working knowledge to use properly. The instruction pamphlet would benefit from better graphics and illustrations.
The scanner has three modes; wood, metal or live electrical. In the wood mode it actually scans for all three, and will display the various signals and graphs on the display. It also identifies the center point of wood studs or metal objects. Selecting metal mode excludes wood and scans for only ferrous/non ferrous metals and “live” electrical wires. It is important to note that the scanner detects wires where current is flowing. The warning light may not flash for wires that have no current draw.
The Bosch GMS120 performed very well in all three modes during my testing and use. As recommended in the instructions, I used a thin piece of cardboard over the uneven ceiling texture, and it detected the joists perfectly. Now I don’t have to drill and patch holes in the ceiling when looking for the joists. The scanner could be more user friendly with better graphics in the display, but it’s still a giant leap above the cheap stud finders.
This stud finder really sounds like it does it all: find studs, live wires, and metal in the wall. However, I was very disappointed that it didn't perform better for the price. My $15 stud finder outperformed it on several of the walls that I tested it out on, which is inexcusable in my book.
Initial impressions: - The stud finder is a little bit larger than most I've used in the past. - Bosch packed a lot of features into this, including a 3-color led indicator, a signal strength display, a backlit display, the option to turn sound indications on/off, and the option to turn the backlight on/off. - The through-hole for marking stud locations is a pretty cool feature too.
Wood stud detection: - The main application I planned on using this for was locating studs. I started over an electrical outlet, since I knew there should be a stud on one side of it. I used both stud finders (my old one and this one) simultaneously, and my old one lit up reliably every 16", turning on and off for each side of the stud. The Bosch gave me intermittent indications, some of which were right in the middle of the 16" spans. The centering feature is OK, but requires that you backtrack once you reach the far side of the stud. Even then, it usually gives about a 3/4" range that it calls the "center."
Metal detection: - The best-performing feature is the metal detecting capability. This is the only reason I'm giving it more than one star. I do a bit of woodworking, and missing a nail before I send a board through my planer can cost me $50-60 on a set of knives. So if I find two nails, the scanner has paid for itself. I tried it out by holding a screw on the far side of an 8/4 walnut board, and the scanner gave a strong indication when I passed over the screw's location. It couldn't find a staple through the board though, but it can detect a sewing needle from about 1/4" to 1/2" from the scanner, without anything in between. - If you want a more reliable stud finding method, I'd use the wood detection capability in conjunction with the metal detection feature. Find the general location of the stud with the wood detection, then use the metal detector to scan up and down to find the screws.
Live wire detection: - This thing is garbage when it comes to finding live wires in your walls. I can scan all around electrical outlets and light switches without so much as a peep from it. My old $15 stud finder lights up like crazy when I scan the same areas. I even scanned the extension cord powering an overhead light in my garage, and the Bosch scanner couldn't pick it up even when I touched them together! I had to rub the wire all over the scanner until it lit up. I would definitely NOT trust this thing to find a live wire before I drilled into the wall.
Conclusions: - Unless you are buying this in part for the metal detection capabilities, go with a different scanner. Even then, you may still be able to find a separate stud finder and metal detector for about the same total price.
Pros: metal detection works
Cons: Difficult to Use, poor performance, low accuracy, expensive
As much as i like Bosch products, their wall scanners are not accurate at all. My new $20 scanner scans better than this one. Thanx to Bosch scanner i put a nail into the BX (electrical wire in the wall) under the electrical box that was covered by a painting :-( The Bosch scanner didn't show any electrical in this area and it was a regular sheetrock wall... Ended up returning the unit and paying a huge repair bill... Stay Away from this scanner....
My unit wouldn't pick up anything correctly, wood, metal or electrical. It gave out false readings constantly and led to much aggravation. After some online research I discovered that Bosch sent some faulty units to the states. I called Bosch and they confirmed the bad units being shipped over to the U.S. I attempted to return it to the Home Depot store where I bought it only I had lost the receipt and the store had pulled the stud finder from their shelves so they refused to take it back. Now I am stuck with an $80 paper weight. I will purchase a new one because I trust Bosch products but I will not buy it from Home Depot.
I tryed over and over for it to find a stud and I had more luck knocking on the wall. I returned the item and got my money back. Dewalt is coming out with a stud finder so I will wait and try that one.
If you are after something to locate studs for hanging a picture or mounting a TV, then this detector is overkill. But if you are a serious modeler, or need a full featured detector, this is the tool for you.
I should warn you that there is leaning curve if you want to make full use of this detector. It presents a lot more information then a standard stud detector. There is the audio output like a basic stud detector. I find it annoying, but you may find it useful. It would be nice if it had a volume control, but at least you can turn it off. And the detector remembers for the next time you use it. It has a detector. It has a centering hole, with a ring around it that changes color to give a quick visual indication. Then there are two bar graphs that show "signal" strength, and centering.
The centering graph is easy to use, but it needs to calibrate itself, so it is not going to show you the center of the stud until you hit the far edge. This is because it does not know how wide the stud is before then. But once it knows, you can back up the scanner and get a good center reading. Once you get used to it, you will love it because it gives you the true center. It works the same for other detection modes.
The strength meter will give you an indication of how deep something is in the wall. Once you get a feel for it, it will let you estimate how deep or how big a metal object is. It is handy for telling the difference between a nail and a buried cable or pipe.
The icons will tell you when it is detecting something for a different mode then you are using. If you pay attention, it can save you from cutting a wire.
The mode button you select lights up to remind you what mode you are in, and there is a light you can turn on to illuminate the LCD display. Someone was thinking when they designed the scanner.
I was able to try it on both plastered and drywalled walls. I was luck to have 2 walls where I know the location of the studs, so I could test how accurate the detector is. For the drywalled walls, it was very accurate. For plaster walls, the results were not as good. From past experience, I was surprised that it could detect the studs at all. It did much better when set to detect the nails fastening the lath to the studs.
How well the live wire detector works depends on the wiring. If it detects the wire, it will give you a nice map of how it runs. But if you have BX, or knob and tube wiring, it may not detect the wiring. The metal sheathing on the BX effectively blocks the signal from the live wires. With knob and tube wiring, it will usually detect the wires to a switch if the switch is off, and their is a light in the circuit. If the switch is on, it may miss the wires. All non-contact detectors run into the same problem. Luckily it is rare to run into knob and tube wiring. I just happen to have a house that is over 100 years old, and has several different types of wiring. So it presents interesting challenges that you don't normally run into!
Pros: All In One, Accurate, Good Size & Weight, Long-Lasting
It was time to treat myself to an upgraded tool to replace my ten year-old stud finder. I bought the Bosch with the thought it was a high-end tool. The device isn't intuitive and requires multiple references to the manual. Most notably, the "Live" wire feature didn't pick up any live wires at all. I tested it against a power cord for a radio and then it worked, but wouldn't pick up electrical in known locations. The first stud it identified now has a molly bolt in its place. This tool is going back.
I was hoping to detect joists behind a plaster ceiling. The plaster thickness variation resulted in false detections. I ended up drilling small holes in the ceiling to find the joist. The other features for metal detection and live wire detection worked OK.
I had just remodeled my bathroom so I knew where all the studs and electrical was located. It worked great to find the studs. The display showed where the center was clearly. It even has a hole to mark on the wall.
But I tried the electrical setting and it found the live wires sometimes and sometimes not. I even tried it over exposed wires and it didn't sound off.
Overall, it worked great for wood, not so great for electrical. I didn't have an occasion to try it on steel setting.
This is a very good and solid wall scanner, it does what it says and is very accurate in finding studs behind drywall. It has a bunch of nice features and I prefer to use it over my cheaper Zircon stud finder.
It has a nice opening so that you can easily mark the drilling location. A simple but very convenient feature. The display, lights, and tones are all very useful especially when working in tight locations or on ladders.
I wanted to use this to locate floor joists under berber carpet in order to drive some screws to fix flloor squeeks. The manual says it can do such job. I was disappointed with its inability to detect those joists. It kept beeping like crazy and gave irregular results no matter which direction I ran. My Zircon stud finder also struggled and couldn't get this job done so I'm sure this has a lot to do with the type of carpet and thick undercarpet layer.
I also tested the feature to detect wiring in the wall, and this works well as described.
I did not test the feature of detecting rebar in concrete walls.
I cannot give it 5 stars since I was expecting a better result for undercarpet floor joist detection.
Pros: Easy to Use, All In One, Sturdy, Accurate, Strong, Good Size & Weight
This is much more accurate than my top of the line Zircon unit. It also warns you of live electric even if you have it in wood stud mode. As with all stud finders this works best with drywall rather than plaster/lath walls but it will locate studs and electric even in those tough situations.
I'm a home handyman and have occasional use for a stud-finder. This wall scanner looked promising, but I found it more difficult to use than my inexpensive LED stud finder.
The biggest problem is that it takes as many as 5 passes, to zero in on a stud. Even then, it can claim the center is far enough off that a nail would miss the stud. When I did a fast sweep across the wall looking for a stud, it would occasionally give no indication that a stud was passed. I tested how long it took to zero in on the center of a stud with this scanner and my old stud finder and the scanner took twice as long - 6 seconds and 5 passes compared to 3 seconds and 1 pass (which actually found the two edges of the stud, from which I could mark the center).
There are several usability problems. The LCD display is hard to read in most conditions unless the backlight is turned on. With the backlight on, I cannot read the display if my eyes are above it - I either have to hold the scanner at eye level or turn it upside down.
The audible tone is fairly loud and of an annoying pitch. I turned it off right away. It does sound to indicate when within 6" or so of a stud (yellow light territory), but then keeps sounding for the (up to) 5 passes I have to make to zero in on the stud.
Speaking of the lighted ring - it's a useful idea but I found "green" meaning "no stud" and "red" meaning "stud found" to be counter-intuitive - I wanted it the other way around. I can understand using red to mean "stop moving" but I associate red with bad things, not good.
Another problem I had were with the instructions that (1) all 3 pads on the back had to contact the wall surface (2) that the hand holding the scanner couldn't touch the wall surface and (3) that your other hand couldn't touch the wall, and (4) when scanning a wall with an uneven surface place thin cardboard on the surface and scan over the cardboard.
Most of my walls are textured. With my old LED stud finder I used my fingertips to hold the finder slightly off the wall so it didn't snag on the texture. When I did this with the Bosch scanner, it found a stud every few inches. So I got some cardboard and had better results, but then my other hand was touching the wall since I was holding the cardboard and trying to move it with the scanner. The contact pads on the back of the scanner are pretty soft and I managed to create some grooves in them trying to scan the textured wall. I ended up putting transparent tape over the pads to protect them. This didn't seem to affect the operation of the scanner.
I also tested locating live electrical wires and had no luck, even with over stud bays I know contain live wires.
It's possible that with practice and regular use this would be a good tool, but for my occasional needs I'll reach for my old stud finder first.
Pros: Durable, All In One, Sturdy, Strong, Long-Lasting
I've had many, many, many stud finders that do many things. This one is just another fancy looking stud finder that can do multiple things. As for finding wood studs, it works, but its precision is not repeatable. I would follow the instructions and it would consistently find a different center on the stud. As for finding metal its good, but could be more accurate as well. I personally have been using magnets to find the screws/nails that are holding up the drywall and that is the most accurate thing i have ever used. For a bosch product, I would have expected more.
Pros: Easy to Use, Good Size & Weight, Light Weight
The device itself looks to be of good quality, but what I had purchased had been used, repackaged and sold for new. Be careful with your purchases and either return it to the store or ask for a credit or a refund.
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Review 20 for Digital Wall Scanner
PostedSeptember 26, 2014
No, I do not recommend this product.
Needed to trace standard 120 volt, 60 Hz house wiring behind sheet rock walls. This unit couldn't find a wire until virtually in contact with it. I literally dismounted a live outlet to expose the hot wires and check whether the unit worked at all. Yes, I did read and follow the directions. I have a cheap pocket pen detector that works just as well. This waste if time and money is on its way back to the store.