Mounting a flight controller with soft pads is really about finding the balance between isolation and stability. The goal is to reduce high-frequency vibration from the frame and motors without letting the board move around so much that it touches the frame, plugs, or stack hardware. If the FC is too rigidly mounted, gyro noise can get worse. If it is too loose, you can end up with intermittent contact, damaged pads, or weird flight behavior from the board bouncing around.
The most common setup is to use the soft gummies or rubber grommets that come with the stack, with the flight controller sitting on top of them and a screw passing through from the bottom plate or standoffs. The key is not to crush the soft material. Tighten the nuts or screws just enough to keep the FC secure, then stop. If the gummies bulge heavily, flatten out, or look squashed, you’ve probably gone too far. They should compress slightly, not get pinched into a solid lump.
It also matters what hardware you use. Make sure the screws are the right length so they do not bottom out against the board or stick up into components. Nylon screws are sometimes used, but metal screws with the proper grommets are more common and usually hold better. If your stack uses vibration-damping silicone bushings, install them in the order recommended by the manufacturer. Some systems are designed to have the grommet sit in the frame plate first, then the FC rests on top; others are the opposite. Following the intended stack order helps a lot.
A good practical tip is to check that the FC has a little bit of side-to-side resilience but cannot shift freely. You should be able to press on it and feel the isolation, yet it should return to position without wobbling. Also watch the clearance around the USB port, receiver wires, ESC plug, and any capacitor. Soft mounting can change the height of the board slightly, so make sure nothing is strained or pressed against another part of the frame.
If you are using foam pads instead of gummies, keep in mind that foam can compress over time and with heat. That makes it less predictable than proper vibration-damping grommets. Foam can work for very light builds or temporary setups, but for a race quad or anything that sees hard impacts, the usual rubberized soft mount is more reliable.
After mounting, inspect the board from all sides. It should be level, not tilted, and nothing should be rubbing on the frame. Once the quad is built, check your blackbox logs or motor noise if you have them. If you see clean gyro traces and the tune feels solid, the mount is probably doing its job. If not, the issue may be the props, motor balance, frame resonance, or overly stiff mounting.
In short: use the right soft mounts, do not overtighten, keep the FC centered and clear of other parts, and make sure it is isolated but not loose. If you want, experienced builders here can tell you the exact mounting order they use on different frames and stacks.
