I would like to mount a computer under a desktop made from particle board, the desktop is 1/2 inch thick, the computer plus mount weighs about 25lbs. Would the particle board hold?
How could I mount the computer to the underside of the desk and ensure it doesn't fall and break?
While there's no problem mounting things to particle board as others have described, 1/2" is just too thin to work with. I would mount another board under your desk using construction or wood glue, at least doubling the current thickness of the top.
After that has set up for a day, I'd mount with 3/4" screws (or longer, depending on final thickness), properly piloted.
I've mounted many things to 3/4" particle board from below, including dual coat hooks that my kids have used for years. 1/2" just doesn't offer enough grab. It's likely that the screws will pull out a layer of material when it all comes crashing down.
Most of the desks in cubicles and modular furniture are made of particle board and they are able to assemble and mount things with screws, so it should not be a problem. They use special coarse thread screws that are made for particle board.
They make all kinds of under desk mounts - here's one:
The thickness of the material will limit the length of screw you can use; with thin materials, you may need to use more screws for a given task. I'd say as long as you get four screws in, you'll be safe with a 25 pound computer.
The answers are good ..just in case you still worry, you also can drill through the board and use a screw, big washer and nut to secure. My tip: if your particle board is bigger than the computer, make sure it is supported by a good structure around it, or your board will bend over time.
